PURIFIED HEPATITIS C VIRUS ENVELOPE PROTEINS FOR DIAGNOSTIC AND THERAPEUTIC USE

Abstract: The present invention relates to a method for purifying recombinant HCV single or specific oligomeric envelope proteins selected from the group consisting of E1 and/or E2 and/or E1/E2, characterized in that upon lysing the transformed host cells to isolate the recombinantly expressed protein a disulphide bond cleavage or reduction step is carried out with a disulphide bond cleavage agent. The present invention also relates to a composition isolated by such a method. The present invention also relates to the diagnostic and therapeutic application of these compositions. Furthermore, the invention relates to the use of HCV E1 protein and peptides for prognosing and monitoring the clinical effectiveness and/or clinical outcome of HCV treatment.

Description: PURIFIED HEPATITIS C VIRUS ENVELOPE PROTEINS FOR DIAGNOSTIC AND THERAPEUTIC USE Field of the invention The present invention relates to the general fields of recombinant protein expression, purification of recombinant proteins, synthetic peptides diagnosis of HCV infection, prophylactic treatment against HCV infection and to the prognosis/monitoring of the clinical efficiency of treatment of an individual with chronic hepatitis, or the prognosis/monitoring of natural disease More particularly, the present invention relates to purification methods for hepatitis C virus envelope proteins, the use in diagnosis, prophylaxis or therapy of HCV envelope proteins purified according to the methods described in the present invention, the use of single or specific oligomeπc E 1 and/or E2 and/or E 1 /E2 envelope proteins in assays for monitoring disease, and/or diagnosis of disease, and/or treatment of disease The invention also relates to epitopes of the E 1 and/or E2 envelope proteins and monoclonal antibodies thereto, as well their use in diagnosis, prophylaxis or treatment Background of the invention The E2 protein purified from cell lysates according to the methods described in the present invention reacts with approximately 95 % of patient sera This reactivity is similar to the reactivity obtained with E2 secreted from CHO cells (Spaete et al , 1 992) However, the intracellularly expressed form of E2 may more closely resemble the native viral envelope protein because it contains high mannose carbohydrate motifs, whereas the E2 protein secreted from CHO cells is further modified with galactose and sialic acid sugar moieties When the aminoterminal half of E2 is expressed in the baculovirus system, only about 1 3 to 21 % of sera from several patient groups can be detected (Inoue et al., 1 992). After expression of E2 from E coli, the reactivity of HCV sera was even lower and ranged from 14 (Yokosuka et al , 1 992) to 1 7 % (Mita et al , 1 992) About 75 % of HCV sera (and 95% of chronic patients) are antι-E1 positive using the purified, vaccinia-expressed recombinant E 1 protein of the present invention, in sharp contrast with the results of Kohara et al (1 992) and Hsu et al ( 1 993) hara et al used a vaccinia-virus expressed E 1 protein and detected antι-E 1 antibodies in 7 * 23 °o of patients, while Hsu et al. only detected 1 4/50 (28 °o ) sera using baculovirus- e -K pressed E 1 . These results show that not only a good expression system but also a good purification protocol are required to reach a high reactivity of the envelope proteins with human patient sera. This can be obtained using the proper expression system and/or purification protocols of the present invention which guarantee the conservation of the natural folding of the protein and the purification protocols of the present invention which guarantee the elimination of contaminating proteins and which preserve the conformation, and thus the reactivity of the HCV envelope proteins. The amounts of purified HCV envelope protein needed for diagnostic screening assays are in the range of grams per year. For vaccine purposes, even higher amounts of envelope protein would be needed. Therefore, the vaccinia virus system may be used for selecting the best expression constructs and for limited upscaling, and large-scale expression and purification of single or specific oligomeπc envelope proteins containing high-mannose carbohydrates may be achieved when expressed from several yeast strains. In the case of hepatitis B for example, manufacturing of HBsAg from mammalian cells was much more costly compared with yeast-derived hepatitis B vaccines. Aims of the invention It is an aim of the present invention to provide a new purification method for recombinantly expressed El and/or E2 and/or E1 /E2 proteins such that said recombinant proteins are directly usable for diagnostic and vaccine purposes as single or specific oligomeπc recombinant proteins free from contaminants instead of aggregates. It is another aim of the present invention to provide compositions comprising purified (single or specific oligomeπc) recombinant E l and/or E2 and/or E 1 /E2 glycoproteins comprising conformational epitopes from the E 1 and/or E2 domains of HCV. It is yet another aim of the present invention to provide novel recombinant vector constructs for recombinantly expressing El and/or E2 and/or E 1 /E2 proteins, as well as host cells transformed with said vector constructs. It is also an aim of the present invention to provide a method for producing and purifying recombinant HCV E 1 and/or E2 and/or E 1 /E2 proteins. It is also an aim of the present invention to provide diagnostic and immunogenic uses of the recombinant HCV E 1 and/or E2 and/or E 1 /E2 proteins of the present invention, as well as to provide kits for diagnostic use vaccines or therapeutics comprising any of the recombinant HCV E 1 and/or E2 and/or E 1 /E2 proteins of the present invention It is further an aim of the present invention to provide for a new use of E 1 , E2, and/or E 1 /E2 proteins, or suitable parts thereof, for monitoπng/prognosing the response to treatment of patients (e.g with interferon) suffering from HCV infection It is also an aim of the present invention to provide for the use of the recombinant E 1 , E2, and/or E 1 /E2 proteins of the present invention in HCV screening and confirmatory antibody tests It is also an aim of the present invention to provide E 1 and/or E2 peptides which can be used for diagnosis of HCV infection and for raising antibodies Such peptides may also be used to isolate human monoclonal antibodies It is also an aim of the present invention to provide monoclonal antibodies, more particularly human monoclonal antibodies or mouse monoclonal antibodies which are humanized, which react specifically with E 1 and/or E2 epitopes, either comprised in peptides or conformational epitopes comprised in recombinant proteins It is also an aim of the present invention to provide possible uses of antι-E 1 or antι-E2 monoclonal antibodies for HCV antigen detection or for therapy of chronic HCV infection. It is also an aim of the present invention to provide kits for monitoπng/prognosing the response to treatment (e.g. with interferon) of patients suffering from HCV infection or monitoπng/prognosing the outcome of the disease All the aims of the present invention are considered to have been met by the embodiments as set out below. Definitions The following definitions serve to illustrate the different terms and expressions used in the present invention. The term 'hepatitis C virus single envelope protein' refers to a polypeptide or an analogue thereof (e.g mimotopes) comprising an ammo acid sequence (and/or ammo acid analogues) defining at least one HCV epitope of either the E1 or the E2 region These single envelope proteins in the broad sense of the word may be both monomeπc or homo-oligomeric forms of recombinantly expressed envelope proteins Typically the sequences defining the epitope correspond to the ammo acid sequence of either the E 1 or the E2 region of HCV (either identically or via substitution of analogues of the native ammo acid residue that do not destroy the epitope) In general, the epitope-definmg sequence will be 3 or more ammo acids in length, more typically, 5 or more ammo acids in length, more typically 8 or more ammo acids in length, and even more typically 1 0 or more ammo acids in length With respect to conformational epitopes, the length of the epitope-definmg sequence can be subject to wide variations, since it is believed that these epitopes are formed by the three-dimensional shape of the antigen (e g folding) Thus, the ammo acids defining the epitope can be relatively few in number, but widely dispersed along the length of the molecule being brought into the correct epitope conformation via folding The portions of the antigen between the residues defining the epitope may not be critical to the conformational structure of the epitope For example, deletion or substitution of these intervening sequences may not affect the conformational epitope provided sequences critical to epitope conformation are maintained (e.g. cystemes involved in disulfide bonding, glycosylation sites, etc. ) A conformational epitope may also be formed by 2 or more essential regions of subunits of a homoohgomer or heterooligomer. The HCV antigens of the present invention comprise conformational epitopes from the E 1 and/or E2 (envelope) domains of HCV The E1 domain, which is believed to correspond to the viral envelope protein, is currently estimated to span ammo acids 1 92-383 of the HCV polyprotein (Hijikata et al., 1 991 ) Upon expression in a mammalian system (glycosylated), it is believed to have an approximate molecular weight of 35 kDa as determined via SDS-PAGE. The E2 protein, previously called NS 1 , is believed to span ammo acids 384-809 or 384-746 (Grakoui et al., 1 993) of the HCV polyprotein and to also be an envelope protein. Upon expression in a vaccinia system (glycosylated), it is believed to have an apparent gel molecular weight of about 72 kDa. It is understood that these protein endpoints are approximations (e g the carboxy terminal end of E2 could lie somewhere in the 730-820 ammo acid region, e.g ending at ammo acid 730, 735, 740, 742, 744, 745, preferably 746, 747, 748, 750, 760, 770, 780, 790, 800, 809, 81 0, 820) The E2 protein may also be expressed together with the E1 , P7 (aa 747-809), NS2 (aa 81 0-1 026), NS4A (aa 1 658-1 71 1 ) or NS4B (aa 1 71 2-1 972). Expression together with these other HCV proteins may be important for obtaining the correct protein folding. It is also understood that the isolates used in the examples section of the present invention were not intended to limit the scope of the invention and that any HCV isolate from type 1 , 2, 3, 4, 5, 6, 7, 8, 9, 1 0 or any other new genotype of HCV is a suitable source of E1 and/or E2 sequence for the practice of the present invention. The E1 and E2 antigens used in the present invention may be full-length viral proteins, substantially full-length versions thereof, or functional fragments thereof (e.g. fragments which are not missing sequence essential to the formation or retention of an epitope). Furthermore, the HCV antigens of the present invention can also include other sequences that do not block or prevent the formation of the conformational epitope of interest. The presence or absence of a conformational epitope can be readily determined though screening the antigen of interest with an antibody (polyclonal serum or monoclonal to the conformational epitope) and comparing its reactivity to that of a denatured version of the antigen which retains only linear epitopes (if any). In such screening using polyclonal antibodies, it may be advantageous to adsorb the polyclo ial serum first with the denatured antigen and see if it retains antibodies to the antigen of interest. The HCV antigens of the present invention can be made by any recombinant method that provides the epitope of intrest. For example, recombinant intracellular expression in mammalian or insect cells is a preferred method to provide glycosylated E1 and/or E2 antigens in 'native' conformation as is the case for the natural HCV antigens. Yeast cells and mutant yeast strains (e.g. mnn 9 mutant (Kniskern et al., 1 994) or glycosylation mutants derived by means of vanadate resistence selection (Ballou et al., 1 991 )) may be ideally suited for production of secreted high-mannose-type sugars; whereas proteins secreted from mammalian cells may contain modifications including galactose or sialic acids which may be undesirable for certain diagnostic or vaccine applications. However, it may also be possible and sufficient for certain applications, as it is known for proteins, to express the antigen in other recombinant hosts (such as E. coli) and renature the protein after recovery. The term 'fusion polypeptide' intends a polypeptide in which the HCV antιgen(s) are part of a single continuous chain of amino acids, which chain does not occur in nature. The HCV antigens may be connected directly to each other by peptide bonds or be separated by intervening amino acid sequences. The fusion polypeptides may also contain amino acid sequences exogenous to HCV. The term 'solid phase' intends a solid body to which the individual HCV antigens or the fusion polypeptide comprised of HCV antigens are bound covalently or by noncovalent means such as hydrophobic adsorption The term 'biological sample' intends a fluid or tissue of a mammalian individual (e g an anthropoid, a human) that commonly contains antibodies produced by the individual, more particularly antibodies against HCV The fluid or tissue may also contain HCV antigen. Such components are known in the art and include, without limitation, blood, plasma, serum, urine, spinal fluid, lymph fluid, secretions of the respiratory, intestinal or genitourinary tracts, tears, saliva, milk, white blood cells and myelomas Body components include biological liquids The term 'biological liquid' refers to a fluid obtained from an organism. Some biological fluids are used as a source of other products, such as clotting factors (e.g. Factor VIII, C), serum albumin, growth hormone and the like In such cases, it is important that the source of biological fluid be free of contamination by virus such as HCV. The term 'immunologically reactive' means that the antigen in question will react specifically with anti-HCV antibodies present in a body component from an HCV infected individual. The term 'immune complex' intends the combination formed when an antibody binds to an epitope on an antigen. 'E1 ' as used herein refers to a protein or polypeptide expressed within the first 400 ammo acids of an HCV polyprotein, sometimes referred to as the E, ENV or S protein. In its natural form it is a 35 kDa glycoprotein which is found in strong association with membranes. In most natural HCV strains, the E1 protein is encoded in the viral polyprotein following the C (core) protein. The E1 protein extends from approximately ammo acid (aa) 1 92 to about aa 383 of the full-length polyprotein. The term 'E1 ' as used herein also includes analogs and truncated forms that are immunologically cross-reactive with natural E 1 , and includes E 1 proteins of genotypes 1 , 2, 3, 4, 5, 6, 7, 8, 9, 1 0, or any other newly identified HCV type or subtype. 'E2' as used herein refers to a protein or polypeptide expressed within the first 900 ammo acids of an HCV polyprotein, sometimes referred to as the NS 1 protein In its natural form it is a 72 kDa glycoprotein that is found in strong association with membranes. In most natural HCV strains, the E2 protein is encoded in the viral polyprotein following the E1 protein. The E2 protein extends from approximately ammo acid position 384 to ammo acid position 746, another form of E2 extends to ammo acid position 809. The term 'E2' as used herein also includes analogs and truncated forms that are immunologically cross-reactive with natural E2. For example, insertions of multiple codons between codon 383 and 384, as well as deletions of am o acids 384- 387 have been reported by Kato et al. ( 1 992) . 'E 1 /E2' as used herein refers to an oligomeπc form of envelope proteins containing at least one E 1 component and at least one E2 component. The term 'specific oligomeπc' E 1 and/or E2 and/or E 1 /E2 envelope proteins refers to all possible oligomeπc forms of recombinantly expressed E 1 and/or E2 envelope proteins which are not aggregates. E 1 and/or E2 specific oligomeπc envelope proteins are also referred to as homo-oligomeric E 1 or E2 envelope proteins (see below) . The term 'single or specific oligomeπc' E1 and/or E2 and/or E1 /E2 envelope proteins refers to single monomeπc E 1 or E2 proteins (single in the strict sense of the word) as well as specific oligomeπc E 1 and/or E2 and /or E l /E2 recombinantly expressed proteins. These single or specific oligomeπc envelope proteins according to the present invention can be further defined by the following formula (E 1 ) X (E2) wherein x can be a number between 0 and 1 00, and y can be a number between o and 1 00, provided that x and y are not both 0. With x = 1 and y = 0 said envelope proteins include monomeric E1 . The term 'homo-oligomer' as used herein refers to a complex of E1 and/or E2 containing more than one E1 or E2 monomer, e.g. E 1 /E 1 dimers, E 1 /E 1 /E 1 trimers or E 1 /E 1 /E 1 /E 1 tetramers and E2/E2 dimers, E2/E2/E2 trimers or E2/E2/E2/E2 tetramers, E 1 pentamers and hexamers, E2 pentamers and hexamers or any higher-order homo- oligomers of E 1 or E2 are all 'homo-oligomers' within the scope of this definition. The oligomers may contain one, two, or several different monomers of E 1 or E2 obtained from different types or subtypes of hepatitis C virus including for example those described in an international application published under WO 94/25601 and European application No. 948701 66.9 both by the present applicants. Such mixed oligomers are still homo-oligomers within the scope of this invention, and may allow more universal diagnosis, prophylaxis or treatment of HCV. The term 'purified' as applied to proteins herein refers to a composition wherein the desired protein comprises at least 35 % of the total protein component in the composition. The desired protein preferably comprises at least 40%, more preferably at least about 50%, more preferably at least about 60%, still more preferably at least about 70%, even more preferably at least about 80%, even more preferably at least about 90%, and most preferably at least about 95 % of the total protein component "• composition may contain other compounds such as carbohydrates, salts, lipids, so nts, and the like, withouth affecting the determination of the percentage purity as used herein. An 'isolated' HCV protein intends an HCV protein composition that is at least 35 % pure. The term 'essentially purified proteins' refers to proteins purified such that they can be used for in vitro diagnostic methods and as a therapeutic compound These proteins are substantially free from cellular proteins, vector-derived proteins or other HCV viral components. Usually these proteins are purified to homogeneity (at least 80% pure, preferably, 90%, more preferably 95 %, more preferably 97 %, more preferably 98 %, more preferably 99%, even more preferably 99.5 %, and most preferably the contaminating proteins should be undetectable by conventional methods like SDS-PAGE and silver staining. The term 'recombinantly expressed' used within the context of the present invention refers to the fact that the proteins of the present invention are produced by recombinant expression methods be it in prokaryotes, or lower or higher eukaryotes as discussed in detail below. The term 'lower eukaryote' refers to host cells such as yeast, fungi and the like. Lower eukaryotes are generally (but not necessarily) unicellular. Preferred lower eukaryotes are yeasts, parti cularl y species within S accharo m yces, Schizosaccharomvces, Kluveromvces. Pichia (e.g. Pichia pastoπs), Hansenula (e.g. Hansenula polvmorpha). Yarowia, Schwaniomvces, Schizosaccharomvces, Zvqosaccharomvces and the like. Saccharomyces cerevisiae, S. carlsberαensis and K. lactis are the most commonly used yeast hosts, and are convenient fungal hosts. The term 'prokaryotes' refers to hosts such as E.coli, Lactobacillus, Lactococcus. Salmonella. Streptococcus. Bacillus subtilis or Streptomvces. Also these hosts are contemplated within the present invention. The term 'higher eukaryote' refers to host cells derived from higher animals, such as mammals, reptiles, insects, and the like. Presently preferred higher eukaryote host cells are derived from Chinese hamster (e.g. CHO), monkey (e.g. COS and Vero cells), baby hamster kidney (BHK), pig kidney (PK1 5), rabbit kidney 1 3 cells (RK 1 3), the human osteosarcoma cell line 143 B, the human cell line HeLa and human hepatoma cell lines like Hep G2, and insect cell lines (e.g. Spodoptera fruqiperda). The host cells may be provided in suspension or flask cultures, tissue cultures, organ cultures and the like. Alternatively the host cells may also be transgenic animals The term 'polypeptide' refers to a polymer of ammo acids and does not refer to a specific length of the product, thus, peptides, o gopeptides and proteins are included within the definition of polypeptide This term also does not refer to or exclude post- expression modifications of the polypeptide, for example, glycosylations, acetylations, phosphorylations and the like Included within the definition are, for example, polypeptides containing one or more analogues of an ammo acid (including for example, unnatural ammo acids, PNA, etc ), polypeptides with substituted linkages, as well as other modifications known in the art, both naturally occurring and non-naturally occurring The term 'recombinant polynucleotide or nucleic acid' intends a polynucleotide or nucleic acid of genomic, cDNA, semisynthetic, or synthetic origin which, by virtue of its origin or manipulation • (1 ) is not associated with all or a portion of a polynucleotide with which it is associated in nature, (2) is linked to a polynucleotide other than that to which it is linked in nature, or (3) does not occur in nature The term 'recombinant host cells', 'host cells', 'cells' , 'cell lines', 'cell cultures', and other such terms denoting microorganisms or higher eukaryotic cell lines cultured as unicellular entities refer to cells which can be or have been, used as recipients for a recombinant vector or other transfer polynucleotide, and include the progeny of the original cell which has been transfected. It is understood that the progeny of a single parental cell may not necessarily be completely identical in morphology or in genomic or total DNA complement as the original parent, due to natural, accidental, or deliberate mutation. The term 'replicon' is any genetic element, e.g., a plasmid, a chromosome, a virus, a cosmid, etc., that behaves as an autonomous unit of polynucleotide replication within a cell; i.e., capable of replication under its own control The term 'vector' is a replicon further comprising sequences providing replication and/or expression of a desired open reading frame The term 'control sequence' refers to polynucleotide sequences which are necessary to effect the expression of coding sequences to which they are ligated The nature of such control sequences differs depending upon the host organism; in prokaryotes, such control sequences generally include promoter, πbosomal binding site, and terminators; in eukaryotes, generally, such control sequences include promoters, terminators and, in some instances, enhancers. The term 'control sequences' is intended to include, at a minimum, all components whose presence is necessary for expression, and may also include additional components whose presence is advantageous, for example, leader sequences which govern secretion. The term 'promoter' is a nucleotide sequence which is comprised of consensus sequences which allow the binding of RNA polymerase to the DNA template in a manner such that mRNA production initiates at the normal transcription initiation site for the adjacent structural gene. The expression 'operably linked' refers to a juxtaposition wherein the components so described are in a relationship permitting them to function in their intended manner. A control sequence 'operably linked' to a coding sequence is gated in such a way that expression of the coding sequence is achieved under conditions compatible with the control sequences. An 'open reading frame' (ORF) is a region of a polynucleotide sequence which encodes a polypeptide and does not contain stop codons; this region may represent a portion of a coding sequence or a total coding sequence. A 'coding sequence' is a polynucleotide sequence which is transcribed into mRNA and/or translated into a polypeptide when placed under the control of appropriate regulatory sequences. The boundaries of the coding sequence are determined by a translation start codon at the 5'-terminus and a translation stop codon at the 3'- terminus. A coding sequence can include but is not limited to mRNA, DNA (including cDNA), and recombinant polynucleotide sequences. As used herein, 'epitope' or 'antigenic determinant' means an amino acid sequence that is immunoreactive. Generally an epitope consists of at least 3 to 4 am o acids, and more usually, consists of at least 5 or 6 amino acids, sometimes the epitope consists of about 7 to 8, or even about 10 amino acids. As used herein, an epitope of a designated polypeptide denotes epitopes with the same amino acid sequence as the epitope in the designated polypeptide, and immunologic equivalents thereof. Such equivalents also include strain, subtype ( = genotype), or type(group)-specific variants, e.g. of the currently known sequences or strains belonging to genotypes 1 a, 1 b, 1 c, 1 d, 1 e, I f, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 3a, 3b, 3c. 3d, 3e, 3f, 3g, 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k, 41, 5a, 5b, 6a, 6b, 6c, 7a, 7b, 7c, 8a, 8b, 9a, 9b, 1 0a, or any other newly defined HCV (sub)type. It is to be understood that the amino acids constituting the epitope need not be part of a linear sequence, but may be interspersed by any number of amino acids, thus forming a conformational epitope. The term 'immunogenic' refers to the ability of a substance to cause a humoral and/or cellular response, whether alone or when linked to a carrier, in the presence or absence of an adjuvant 'Neutralization' refers to an immune response that blocks the infectivity, either partially or fully, of an infectious agent A 'vaccine' is an immunogenic composition capable of eliciting protection against HCV, whether partial or complete A vaccine may also be useful for treatment of an individual, in which case it is called a therapeutic vaccine. The term 'therapeutic' refers to a composition capable of treating HCV infection The term 'effective amount' refers to an amount of epitope-beaπng polypeptide sufficient to induce an immunogenic response in the individual to which it is administered, or to otherwise detectably immunoreact in its intended system (e g., immunoassay). Preferably, the effective amount is sufficient to effect treatment, as defined above. The exact amount necessary will vary according to the application For vaccine applications or for the generation of po yclonal antiserum / antibodies, for example, the effective amount may vary depending on the species, age, and general condition of the individual, the severity of the condition being treated, the part ular polypeptide selected and its mode of administration, etc. It is also believed that effe ctive amounts will be found within a relatively large, non-critical ranr. An appropriate effective amount can be readily determined using only routine expeπmentat' Preferred ranges of E 1 anα/or Z " ~d '-' M c 2 single J . opecif proteins for prophylaxis of HCV disease are 0.01 to 1 00 μg/dose, prb ieraDly 0.1 to 50 /yg/dose. Several doses may be needed per individual in order to achieve a sufficient immune response and subsequent protection against HCV dιsec->e. Detailed description of the invention More particularly, the present invention contemplates a method for isolating or purifying recombinant HCV single or specific oligomeπc envelope protein selected from the group consisting of E 1 and/or E2 and/or E 1 /E2, characterized in that upon lysmg the transformed host cells to isolate the recombinantly expressed protein a disulphide bond cleavage or reduction step is carried out with a disculphide bond cleaving agent. The essence of these 'single or specific oligomeπc' envelope proteins of the invention is that they are free from contaminating proteins and that they are not disulphide bond linked with contaminants The proteins according to the present invention are recombinantly expressed in lower or higher eukaryotic cells or in prokaryotes The recombinant proteins of the present invention are preferably glycosylated and may contain high-mannose-type, hybrid, or complex glycosylations Preferentially said proteins are expressed from mammalian cell lines as discussed in detail in the Examples section, or in yeast such as in mutant yeast strains also as detailed in the Examples section The proteins according to the present invention may be secreted or expressed within components of the cell, such as the ER or the Golgi Apparatus Preferably, however, the proteins of the present invention bear high-mannose-type glycosylations and are retained in the ER or Golgi Apparatus of mammalian cells or are retained in or secreted from yeast cells, preferably secreted from yeast mutant strains such as the mnn9 mutant (Kniskern et al., 1 994), or from mutants that have been selected by means of vanadate resistence (Ballou et al., 1 991 ) Upon expression of HCV envelope proteins, the present inventors could show that some of the free thiol groups of cystemes not involved in intra- or inter-molecular disulphide bridges, react with cystemes of host or expression-system-derived (e.g. vaccinia) proteins or of other HCV envelope proteins (single or oligomeπc), and form aspecific intermolecular bridges. This results in the formation of 'aggregates' of HCV envelope proteins together with contaminating proteins It was also shown in WO 92/08734 that 'aggregates' were obtained after purification, but it was not described which protein interactions were involved. In patent application WO 92/08734, recombinant E1 /E2 protein expressed with the vaccinia virus system were partially purified as aggregates and only found to be 70% pure, rendering the purified aggregates not useful for diagnostic, prophylactic or therapeutic purposes. Therefore, a major aim of the present invention resides in the separation of single or specific-oligomeπc HCV envelope proteins from contaminating proteins, and to use the purified proteins ( > 95 % pure) for diagnostic, prophylactic and therapeutic purposes. To those purposes, the present inventors have been able to provide evidence that aggregated protein complexes ('aggregates') are formed on the basis of disulphide bridges and non-covalent protein-protein interactions. The present invention thus provides a means for selectively cleaving the disulphide bonds under specific conditions and for separating the cleaved proteins from contaminating proteins which greatly interfere with diagnostic, prophylactic and therapeutic applications. The free thiol groups may be blocked (reversibly or irreversibly) in order to prevent the reformation of disulphide bridges, or may be left to oxidize and oligomeπze with other envelope proteins (see definition homo-oligomer) It is to be understood that such protein oligomers are essentially different from the 'aggregates' described in WO 92/08734 and WO 94/01 778, since the level of contaminating proteins is undetectable Said disuphide bond cleavage may also be achieved by ( 1 ) performic acid oxidation by means of cysteic acid in which case the cysteme residues are modified into cysteic acid (Moore et al., 1 963) (2) Sulfitolysis (R-S-S-R → 2 R-S0 3 ) for example by means of sulphite (SO- ,) together with a proper oxidant such as Cu 2 + in which case the cysteme is modified into S-sulpho- cysteme (Bailey and Cole, 1 959). ( 3) Reduction by means of mercaptans, such as dithiotreitol (DDT), β-mercapto-ethanol, cysteme, glutathione Red, e-mercapto-ethylamine, or thioglycollic acid, of which DTT and β-mercapto-ethanol are commonly used (Cleland, 1 964), is the preferred method of this invention because the method can be performed in a water environment and because the cysteme remains unmodified. (4) Reduction by means of a phosphme (e.g. Bu 3 P) (Ruegg and Rudmger, 1 977) All these compounds are thus to be regarded as agents or means for cleaving disulphide bonds according to the present invention. Said disulphide bond cleavage (or reducing) step of the present invention is preferably a partial disulphide bond cleavage (reducing) step (carried out under partial cleavage or reducing conditions). A preferred disulphide bond cleavage or reducing agent according to the present invention is dithiothreitol (DTT). Partial reduction is obtained by using a low concentration of said reducing agent, i.e. for DTT for example in the concentration range of about 0.1 to about 50 mM, preferably about 0.1 to about 20 mM, preferably about 0.5 to about 1 0 mM, preferably more than 1 mM, more than 2 mM or more than 5 mM, more preferably about 1 .5 mM, about 2.0 mM, about 2.5 mM, about 5 mM or about 7.5 mM. Said disulphide bond cleavage step may also be carried out in the presence of a suitable detergent (as an example of a means for cleaving disulphide bonds or in combination with a cleaving agent) able to dissociate the expressed proteins, such as DecylPEG, EMPIGEN-BB, NP-40, sodium cholate, Triton X-1 00. Said reduction or cleavage step (preferably a partial reduction or cleavage step) is carried out preferably in in the presence of (with) a detergent A preferred detergent according to the present invention is Empigen-BB The amount of detergent used is preferably in the range of 1 to 1 0 %, preferably more than 3 °o more preferably about 3 5 % of a detergent such as Empigen-BB A particularly preferred method for obtaining disulphide bond cleavage employs a combination of a classical disulphide bond cleavage agent as detailed above and a detergent (also as detailed above) As contemplated in the Examples section the particular combination of a low concentration of DTT ( 1 5 to 7 5 M) and about 3 5 % of Empigen-BB is proven to be a particularly preferred combination of reducing agent and detergent for the purification of recombinantly expressed E1 and E2 proteins Upon gelf iltration chromatography, said partial reduction is shown to result in the production of possibly dimeπc E 1 protein and separation of this E 1 protein from contaminating proteins that cause false reactivity upon use in immunoassays It is, however, to be understood that also any other combination of any reducing agent known in the art with any detergent or other means known in the art to make the cystemes better accessible is also within the scope of the present invention, insofar as said combination reaches the same goal of disulphide bridge cleavage as the preferred combination examplified in the present invention. Apart from reducing the disulphide bonds, a disulphide bond cleaving means according to the present invention may also include any disulphide bridge exchanging agents (competitive agent being either organic or protemaeous, see for instance Creighton, 1 988) known in the art which allows the following type of reaction to occur R 1 S - S R2 + R3 SH → R1 S - S R3 + R2 SH * R 1 , R2 compounds of protein aggregates * R3 SH- competitive agent (organic, protemaeous) The term 'disulphide bridge exchanging agent' is to be interpretated as including disulphide bond reforming as well as disulphide bond blocking agents. The present invention also relates to methods for purifying or isolating HCV single or specific oligomeπc envelelope proteins as set out above further including the use of any SH group blocking or binding reagent known in the art such as chosen from the following list. Glutathion 5, 5'-dιthιobιs-(2-nιtrobenzoιc acid) or bιs-(3-carboxy-4-nιtrophenyl)-dιsulphιde (DTNB or Ellman's reagent) (Elmann, 1 959) N-ethylmaleimide (NEM; Benesch et al , 1 956) N-(4-dιmethylamιno-3, 5-dιnιtrophenyl) maleimide or Tuppy's maleimide which provides a color to the protein P-chloromercuπbenzoate (Grassetti et al , 1 969) - 4-vιnylpyrιdιne (Friedman and Krull, 1 969) can be liberated after reaction by acid hydrolysis acrylonitπle, can be liberated after reaction by acid hydrolysis (Weil and Seibles, 1 961 ) NEM-biotm (e.g. obtained from Sigma B 1 267) - 2, 2'-dιthιopyrιdιne (Grassetti and Murray, 1 967) 4,4'-dιthιopyrιdιne (Grassetti and Murray, 1 967) 6,6'-dιthιodιnιcontιnιc acid (DTDNA, Brown and Cunnigham, 1 970) 2,2'-dιthιobιs-(5'-nιtropyrιdιne) (DTNP, US patent 35971 60) or other dithiobis (heterocyclic derivative) compounds (Grassetti and Murray, 1 969) A survey of the publications cited shows that often different reagents for sulphydryl groups will react with varying numbers of thiol groups of the same protein or enzyme molecule. One may conclude that this variation in reactivity of the thiol groups is due to the steric environment of these groups, such as the shape of the molecule and the surrounding groups of atoms and their charges, as well as to the size, shape and charge of the reagent molecule or ion. Frequently the presence of adequate concentrations of denaturants such as sodium dodecylsulfate, urea or guanidme hydrochoπde will cause sufficient unfolding of the protein molecule to permit equal access to all of the reagents for thiol groups. By varying the concentration of denaturant, the degree of unfolding can be controlled and in this way thiol groups with different degrees of reactivity may be revealed. Although up to date most of the work reported has been done with p-chloromercuπbenzoate, N-ethylmaleimide and DTNB, it is likely that the other more recently developed reagents may prove equally useful Because of their varying structures, it seems likely, in fact, that they may respond differently to changes in the steric environment of the thiol groups Alternatively, conditions such as low pH (preferably lower than pH 6) for preventing free SH groups from oxidizing and thus preventing the formation of large intermolecular aggregates upon recombinant expression and purification of E 1 and E2 (envelope) proteins are also within the scope of the present invention. A preferred SH group blocking reagent according to the present invention is N- ethylmaleimide (NEM) Said SH group blocking reagent may be administrated during lysis of the recombinant host cells and after the above-mentioned partial reduction process or after any other process for cleaving disulphide bridges Said SH group blocking reagent may also be modified with any group capable of providing a detectable label and/or any group aiding in the immobilization of said recombinant protein to a solid substrate, e g. biotmylated NEM Methods for cleaving cysteme bridges and blocking free cystemes have also been described in Darbre ( 1 987), Means and Feeney ( 1 971 ), and by Wong ( 1 993) A method to purify single or specific oligomeπc recombinant E1 and/or E2 and/or E 1 /E2 proteins according to the present invention as defined above is further characterized as comprising the following steps lysing recombinant E 1 and/or E2 and/or E 1 /E2 expressing host cells, preferably in the presence of an SH group blocking agent, such as N-ethylmaleimide (NEM), and possibly a suitable detergent, preferably Empigen-BB, - recovering said HCV envelope protein by affinity purification for instance by means lectm-chromatography, such as lentil-lectm chromatography, or immunoaffmity chromatography using antι-E 1 and/or antι-E2 specific monoclonal antibodies, followed by, reduction or cleavage of disulphide bonds with a disulphide bond cleaving agent, such as DTT, preferably also in the presence of an SH group blocking agent, such as NEM or Biotm-NEM, and, recovering the reduced HCV E1 and/or E2 and/or E 1 /E2 envelope proteins for instance by gelfiltration (size exclusion chromatography or molecular sieving) and possibly also by an additional Nι 2 + -IMAC chromatography and desalting step. It is to be understood that the above-mentioned recovery steps may also be carried out using any other suitable technique known by the person skilled in the art Preferred lectm-chromatography systems include Galanthus nivalis agglutinm (GNA) - chromatography, or Lens culinaπs aααlutinin (LCA) (lentil) lectm chromatography as illustrated in the Examples section. Other useful lectms include those recognizing high-mannose type sugars, such as Narcissus pseudonarcissus agglutinm (NPA), Pisum sativum agglutinm (PSA), or Allium ursmum agglutinm (AUA) Preferably said method is usable to purify single or specific oligomeπc HCV envelope protein produced intracellularly as detailed above. For secreted E 1 or E2 or E 1 /E2 oligomers, lect s binding complex sugars such as Ricinus communis agglutinm I (RCA I), are preferred lectms. The present invention more particularly contemplates essentially purified recombinant HCV single or specific oligomeπc envelope proteins, selected from the group consisting of E 1 and/or E2 and/or E 1 /E2, characterized as being isolated or purified by a method as defined above. The present invention more particularly relates to the purification or isolation of recombinant envelope proteins which are expressed from recombinant mammalian cells such as vaccinia. The present invention also relates to the purification or isolation of recombinant envelope proteins which are expressed from recombinant yeast cells. The present invention equally relates to the purification or isolation of recombinant envelope proteins which are expressed from recombinant bacterial (prokaryotic) cells. The present invention also contemplates a recombinant vector comprising a vector sequence, an appropriate prokaryotic, eukaryotic or viral or synthetic promoter sequence followed by a nucleotide sequence allowing the expression of the single or specific oligomeric E1 and/or E2 and/or E 1 /E2 of the invention. Particularly, the present invention contemplates a recombinant vector comprising a vector sequence, an appropriate prokaryotic, eukaryotic or viral or synthetic promoter sequence followed by a nucleotide sequence allowing the expression of the single E 1 or E 1 of the invention. Particularly, the present invention contemplates a recombinant vector comprising a vector sequence, an appropriate prokaryotic, eukaryotic or viral or synthetic promoter sequence followed by a nucleotide sequence allowing the expression of the single E 1 or E2 of the invention. The segment of the HCV cDNA encoding the desired E1 and/or E2 sequence inserted into the vector sequence may be attached to a signal sequence. Said signal sequence may be that from a non-HCV source, e.g. the IgG or tissue plasminogen activator (tpa) leader sequence for expression in mammalian cells, or the σ-mating factor sequence for expression into yeast cells, but particularly preferred constructs according to the present invention contain signal sequences appearing in the HCV genome before the respective start points of the E1 and E2 proteins. The segment of the HCV cDNA encoding the desired E 1 and/or E2 sequence inserted into the vector may also include deletions e.g. of the hydrophobic domain(s) as illustrated in the examples section, or of the E2 hypervaπable region I. More particularly, the recombinant vectors according to the present invention encompass a nucleic acid having an HCV cDNA segment encoding the polyprotein starting in the region between ammo acid positions 1 and 1 92 and ending in the region between positions 250 and 400 of the HCV polyprotein, more preferably ending in the region between positions 250 and 341 , even more preferably ending in the region between positions 290 and 341 for expression of the HCV single E 1 protein. Most preferably, the present recombinant vector encompasses a recombinant nucleic acid having a HCV cDNA seqment encoding part of the HCV polyprotein starting in the region between positions 1 1 7 and 1 92, and ending at any position in the region between positions 263 and 326, for expression of HCV single E l protein. Also within the scope of the present invention are forms that have the first hydrophobic domain deleted (positions 264 to 293 plus or minus 8 amino acids), or forms to which a 5'- termmal ATG codon and a 3'-termιnal stop codon has been added, or forms which have a factor Xa cleavage site and/or 3 to 1 0, preferably 6 Histidine codons have been added. More particularly, the recombinant vectors according to the present invention encompass a nucleic acid having an HCV cDNA segment encoding the polyprotein starting in the region between amino acid positions 290 and 406 and ending in the region between positions 600 and 820 of the HCV polyprotein, more preferably starting in the region between positions 322 and 406, even more preferably starting in the region between positions 347 and 406, even still more preferably starting in the region between positions 364 and 406 for expression of the HCV single E2 protein. Most preferably, the present recombinant vector encompasses a recombinant nucleic acid having a HCV cDNA seqment encoding the polyprotein starting in the region between positions 290 and 406, and ending at any position of positions 623, 650, 661 , 673, 71 0, 71 5, 720, 746 or 809, for expression of HCV single E2 protein. Also within the scope of the present invention are forms to which a 5'-terminal ATG codon and a 3'- terminal stop codon has been added, or forms which have a factor Xa cleavage site and/or 3 to 1 0, preferably 6 Histidine codons have been added. A variety of vectors may be used to obtain recombinant expression of HCV single or specific oligomeric envelope proteins of the present invention. Lower eukaryotes such as yeasts and glycosylation mutant strains are typically transformed with plasmids, or are transformed with a recombinant virus. The vectors may replicate within the host independently, or may integrate into the host cell genome Higher eukaryotes may be transformed with vectors, or may be infected with a recombinant virus, for example a recombinant vaccinia virus. Techniques and vectors for the insertion of foreign DNA into vaccinia virus are well known in the art, and utilize, for example homologous recombination. A wide variety of viral promoter sequences, possibly terminator sequences and poly(A)-addιtιon sequences, possibly enhancer sequences and possibly amplification sequences, all required for the mammalian expression, are available in the art. Vaccinia is particularly preferred since vaccinia halts the expression of host cell proteins. Vaccinia is also very much preferred since it allows the expression of E 1 and E2 proteins of HCV in cells or individuals which are immunized with the live recombinant vaccinia virus. For vaccination of humans the avipox and Ankara Modified Virus (AMV) are particularly useful vectors. Also known are insect expression transfer vectors derived from baculovirus Autoqrapha californica nuclear polyhedrosis virus (AcNPV), which is a helper- independent viral expression vector. Expression vectors derived from this system usually use the strong viral polyhedrin gene promoter to drive the expression of heterologous genes. Different vectors as well as methods for the introduction of heterologous DNA into the desired site of baculovirus are available to the man skilled in the art for baculovirus expression. Also different signals for posttranslational modification recognized by insect cells are known in the art. Also included within the scope of the present invention is a method for producing purified recombinant single or specific oligomeric HCV E 1 or E2 or E 1 /E2 proteins, wherein the cysteine residues involved in aggregates formation are replaced at the level of the nucleic acid sequence by other residues such that aggregate formation is prevented. The recombinant proteins expressed by recombinant vectors caarying such a mutated E 1 and/or E2 protein encoding nucleic acid are also within the scope of the present invention. The present invention also relates to recombinant E 1 and/or E2 and/or E 1 /E2 proteins characterized in that at least one of their glycosylation sites has been removed and are consequently termed glycosylation mutants. As explained in the Examples section, different glycosylation mutants may be desired to diagnose (screening, confirmation, prognosis, etc.) and prevent HCV disease according to the patient in question. An E2 protein glycosylation mutant lacking the GLY4 has for instance been found to improve the reactivity of certain sera in diagnosis. These glycosylation mutants are preferably purified according to the method disclosed in the present invention Also contemplated within the present invention are recombinant vectors carrying the nucleic acid insert encoding such a E1 and/or E2 and/or E1 /E2 glycosylation mutant as well as host cells tranformed with such a recombinant vector The present invention also relates to recombinant vectors including a polynucleotide which also forms part of the present invention The present invention relates more particularly to the recombinant nucleic acids as represented in SEQ ID NO 3, 5, 7, 9, 1 1 , 1 3, 21 , 23, 25, 27, 29, 31 , 35, 37, 39, 41 , 43, 45, 47 and 49, or parts thereof. The present invention also contemplates host cells transformed with a recombinant vector as defined above, wherein said vector comprises a nucleotide sequence encoding HCV E 1 and/or E2 and/or E 1 /E2 protein as defined above in addition to a regulatory sequence operably linked to said HCV E 1 and/or E2 and/or E 1 /E2 sequence and capable of regulating the expression of said HCV E1 and/or E2 and/or E1 /E2 protein. Eukaryotic hosts include lower and higher eukaryotic hosts as described in the definitions section. Lower eukaryotic hosts include yeast cells well known in the art. Higher eukaryotic hosts mainly include mammalian cell lines known in the art and include many immortalized cell lines available from the ATCC, inludmg HeLa cells, Chinese hamster ovary (CHO) cells, Baby hamster kidney (BHK) cells, PK 1 5, RK 1 3 and a number of other cell lines. The present invention relates particularly to a recombinant E1 and/or E2 and/or E1 /E2 protein expressed by a host cell as defined above containing a recombinany vector as defined above. These recombinant proteins are particularly purified according to the method of the present invention. A preferred method for isolating or purifying HCV envelope proteins as defined above is further characterized as comprising at least the following steps: growing a host cell as defined above transformed with a recombinant vector according to the present invention or with a known recombinant vector expressing E 1 and/or E2 and/or E 1 /E2 HCV envelope proteins in a suitable culture medium, causing expression of said vector sequence as defined above under suitable conditions, and, lysing said transformed host cells, preferably in the presence of a SH group blocking agent, such as N-ethylmaleimide (NEM ) and possibly a suitable detergent, preferably Empigen-BB recovering said HCV envelope protein by affinity purification such as by means of lectm-chromatography or immunoaffmity chromatography using anti E 1 and/or antι-E2 specific monoclonal antibodies, with said lectm being preferably lentil- lectm or GNA, followed by, incubation of the eluate of the previous step with a disulphide bond cleavage means, such as DTT, preferably followed by incubation with an SH group blocking agent, such as NEM or Biotm-NEM and, - isolating the HCV single or specific oligomeric E 1 and/or E2 and/or E 1 /E2 proteins such as by means of gelfiltration and possibly also by a subsequent NX-IMAC chromatography followed by a desalting step As a result of the above-mentioned proces, E 1 and/or E2 and/or E 1 /E2 proteins may be produced in a form which elute differently from the large aggregates containing vector-derived components and/or cell components in the void volume of the gelfiltration column or the IMAC collumn as illustrated in the Examples section The disulphide bridge cleavage step advantageously also eliminates the false reactivity due to the presence of host and/or expression-system-derived proteins The presence of NEM and a suitable detergent during lysis of the cells may already partly or even completely prevent the aggregation between the HCV envelope proteins and contaminants. Nι + -IMAC chromatography followed by a desalting step is preferably used for contructs bearing a (Hιs) 6 as described by Janknecht et al , 1 991 , and Hochuli et al , 1 988 The present invention also relates to a method for producing monoclonal antibodies in small animals such as mice or rats, as well as a method for screening and isolating human B-cells that recognize anti-HCV antibodies, using the HCV single or specific oligomeric envelope proteins of the present invention The present invention further relates to a composition comprising at least one of the following E 1 peptides as listed in Table 3 E1 -31 (SEQ ID NO 56) spanning ammo acids 1 81 to 200 of the Core/E 1 V 1 region, E 1 -33 (SEQ ID NO 57) spanning ammo acids 1 93 to 21 2 of the E 1 region, E 1 -35 (SEQ ID NO 58) spanning ammo acids 205 to 224 of the E1 V2 region (epitope B), E1-35A (SEQ ID NO 59) spanning ammo acids 208 to 227 of the E1 V2 region (epitope B), 1 bE1 (SEQ ID NO 53) spanning ammo acids 192 to 228 of E1 regions (V1 , C 1 , and V2 regions (containing epitope B)), E1-51 (SEQ ID NO 66) spanning ammo acids 301 to 320 of the E1 region, E1-53 (SEQ ID NO 67) spanning ammo acids 313 to 332 of the E1 C4 region (epitope A), E1-55 (SEQ ID NO 68) spanning ammo acids 325 to 344 of the E1 region. The present invention also relates to a composition comprising at least one of the following E2 peptides as listed in Table 3: Env 67 or E2-67 (SEQ ID NO 72) spanning ammo acid positions 397 to 416 of the E2 region (epitope A, recognized by monoclonal antibody 2F10H10, see Figure 19), Env 69 or E2-69 (SEQ ID NO 73) spanning ammo acid positions 409 to 428 of the E2 region (epitope A), Env 23 or E2-23 (SEQ ID NO 86) spanning positions 583 to 602 of the E2 region (epitope E), Env 25 or E2-25 (SEQ ID NO 87) spanning positions 595 to 614 of the E2 region (epitope E), Env 27 or E2-27 (SEQ ID NO 88) spanning positions 607 to 626 of the E2 region (epitope E), Env 17B or E2-17B (SEQ ID NO 83) spanning positions 547 to 566 of the E2 region (epitope D), Env 13B or E2-13B (SEQ ID NO 82) spanning positions 523 to 542 of the E2 region (epitope C; recognized by monoclonal antibody 16A6E7, see Figure 19). The present invention also relates to a composition comprising at least one of the following E2 conformational epitopes: epitope F recognized by monoclonal antibodies 15C8C1, 12D11F1 and 8G10D1H9, epitope G recognized by monoclonal antibody 9G3E6, epitope H (or C) recognized by monoclonal antibody 10D3C4 and 4H6B2, or, epitope I recognized by monoclonal antibody 17F2C2. The present invention also relates to an E1 or E2 specific antibody raised upon immunization with a peptide or protein composition, with said antibody being specifically reactive with any of the polypeptides or peptides as defined above, and with said antibody being preferably a monoclonal antibody The present invention also relates to an E 1 or E2 specific antibody screened from a variable chain library in plasmids or phages or from a population of human B-cells by means of a process known in the art, with said antibody being reactive with any of the polypeptides or peptides as defined above, and with said antibody being preferably "a monoclonal antibody. The E1 or E2 specific monoclonal antibodies of the invention can be produced by any hybπdoma liable to be formed according to classical methods from splenic cells of an animal, particularly from a mouse or rat, immunized against the HCV polypeptides or peptides according to the invention, as defined above on the one hand, and of cells of a myeloma cell line on the other hand, and to be selected by the ability of the hybπdoma to produce the monoclonal antibodies recognizing the polypeptides which has been initially used for the immunization of the animals The antibodies involved in the invention can be labelled by an appropriate label of the enzymatic, fluorescent, or radioactive type. The monoclonal antibodies according to this preferred embodiment of the invention may be humanized versions of mouse monoclonal antibodies made by means of recombinant DNA technology, departing from parts of mouse and/or human genomic DNA sequences coding for H and L chains from cDNA or genomic clones coding for H and L chains. Alternatively the monoclonal antibodies according to this preferred embodiment of the invention may be human monoclonal antibodies. These antibodies according to the present embodiment of the invention can also be derived from human peripheral blood lymphocytes of patients infected with HCV, or vaccinated against HCV. Such human monoclonal antibodies are prepared, for instance, by means of human peripheral blood lymphocytes (PBL) repopulation of severe combined immune deficiency (SCID) mice (for recent review, see Duchosal et al., 1 992). The invention also relates to the use of the proteins or peptides of the invention, for the selection of recombinant antibodies by the process of repertoire cloning (Persson et al., 1 991 ). Antibodies directed to peptides or single or specific oligomeric envelope proteins derived from a certain genotype may be used as a medicament, more particularly for incorporation into an immunoassay for the detection of HCV genotypes (for detecting the presence of HCV E 1 or E2 antigen), for prognosing/monitormg of HCV disease, or as therapeutic agents. Alternatively, the present invention also relates to the use of any of the above- specified E 1 or E2 specific monoclonal antibodies for the preparation of an immunoassay kit for detecting the presence of E 1 or E2 antigen in a biological sample, for the preparation of a kit for prognosing/monitormg of HCV disease or for the preparation of a HCV medicament. The present invention also relates to the a method for in vitro diagnosis or detection of HCV antigen present in a biological sample, comprising at least the following steps : (i) contacting said biological sample with any of the E 1 and/or E2 specific monoclonal antibodies as defined above, preferably in an immobilized form under appropriate conditions which allow the formation of an immune complex, (n) removing unbound components, (in) incubating the immune complexes formed with heterologous antibodies, which specifically bind to the antibodies present in the sample to be analyzed, with said heterologous antibodies having conjugated to a detectable label under appropriate conditions, (iv) detecting the presence of said immune complexes visually or mechanically (e.g. by means of densitometry, fluoπmetry, coloπmetry). The present invention also relates to a kit for in vitro diagnosis of HCV antigen present in a biological sample, comprising: at least one monoclonal antibody as defined above, with said antibody being preferentially immobilized on a solid substrate, a buffer or components necessary for producing the buffer enabling binding reaction between these antibodies and the HCV antigens present in the biological sample, a means for detecting the immune complexes formed in the preceding binding reaction, possibly also including an automated scanning and interpretation device for inferring the HCV antigens present in the sample from the observed binding pattern. The present invention also relates to a composition comprising E 1 and/or E2 and/or E l /E2 recombinant HCV proteins purified according to the method of the present invention or a composition comprising at least one peptides as specified above for use as a medicament. The present invention more particularly relates to a composition comprising at least one of the above-specified envelope peptides or a recombinant envelope protein composition as defined above, for use as a vaccine for immunizing a mammal, preferably humans, against HCV, comprising administering a sufficient amount of the composition possibly accompanied by pharmaceutically acceptable adjuvant(s), to produce an immune response. More particularly, the present invention relates to the use of any of the compositions as described here above for the preparation of a vaccine as described above. Also, the present invention relates to a vaccine composition for immunizing a mammal, preferably humans, against HCV, comprising HCV single or specific oligomeric proteins or peptides derived from the E 1 and/or the E2 region as described above. Immunogenic compositions can be prepared according to methods known in the art. The present compositions comprise an immunogenic amount of a recombinant E 1 and/or E2 and/or E 1 /E2 single or specific oligomeric proteins as defined above or E 1 or E2 peptides as defined above, usually combined with a pharmaceutically acceptable carrier, preferably further comprising an adjuvant. The single or specific oligomeric envelope proteins of the present invention, either E1 and/or E2 and/or E1 /E2, are expected to provide a particularly useful vaccine antigen, since the formation of antibodies to either E 1 or E2 may be more desirable than to the other envelope protein, and since the E2 protein is cross-reactive between HCV types and the E 1 protein is type-specific. Cocktails including type 1 E2 protein and E 1 proteins derived from several genotypes may be particularly advantageous. Cocktails containing a molar excess of E1 versus E2 or E2 versus E1 may also be particularly useful. Immunogenic compositions may be administered to animals to induce production of antibodies, either to provide a source of antibodies or to induce protective immunity in the animal. Pharmaceutically acceptable carriers include any carrier that does not itself induce the production of antibodies harmful to the individual receiving the composition. Suitable carriers are typically large, slowly metabolized macromolecules such as proteins, polysaccharides, polylactic acids, polyglycohc acids, polymeric amino acids, ammo acid copolymers, and inactive virus particles Such carriers are well known to those of ordinary skill in the art. Preferred adjuvants to enhance effectiveness of the composition include, but are not limited to : aluminim hydroxide (alum), N-acetyl-muramyl-L-threonyl-D-isoglutamine (thr-MDP) as found in U.S. Patent No. 4,606, 91 8, N-acetyl-normuramyl-L-alanyl-D- isoglutamine (nor-MDP), N-acetylmuramyl-L-alanyl-D-ιsoglutamιnyl-L-alanιne-2-( 1 '-2'- dιpalmιtoyl-sn-glycero-3-hydroxyphosphoryloxy)-ethylamιne (MTP-PE) and RIBI, which contains three components extracted from bacteria, monophosphoryl lipid A, trehalose dimycolate, and cell wall skeleton (MPL + TDM + CWS) in a 2 % squalene/Tween 80 emulsion Any of the 3 components MPL, TDM or CWS may also be used alone or combined 2 by 2. Additionally, adjuvants such as Stimulon (Cambridge Bioscience, Worcester, MA) or SAF-1 (Syntex) may be used Further, Complete Freund's Adjuvant (CFA) and Incomplete Freund's Adjuvant (IFA) may be used for non-human applications and research purposes The immunogenic compositions typically will contain pharmaceutically acceptable vehicles, such as water, saline, glycerol, ethanol, etc. Additionally, auxiliary substances, such as wetting or emulsifying agents, pH buffering substances, preservatives, and the like, may be included in such vehicles. Typically, the immunogenic compositions are prepared as injectables, either as liquid solutions or suspensions; solid forms suitable for solution in, or suspension in, liquid vehicles prior to injection may also be prepared. The preparation also may be emulsified or encapsulated in liposomes for enhanced adjuvant effect. The E 1 and E2 proteins may also be incorporated into Immune Stimulating Complexes together with saponins, for example Quil A (ISCOMS). Immunogenic compositions used as vaccines comprise a 'sufficient amount' or 'an immunologically effective amount' of the envelope proteins of the present invention, as well as any other of the above mentioned components, as needed. ' Immunologically effective amount', means that the administration of that amount to an individual, either in a single dose or as part of a series, is effective for treatment, as defined above. This amount varies depending upon the health and physical condition of the individual to be treated, the taxonomic group of individual to be treated (e.g. nonhuman primate, primate, etc.), the capacity of the individual's immune system to synthesize antibodies, the degree of protection desired, the formulation of the vaccine, the treating doctor's assessment of the medical situation, the strain of infecting HCV, and other relevant factors. It is expected that the amount will fall in a relatively broad range that can be determined through routine trials. Usually, the amount will vary from 0.01 to 1 000 μg/dose, more particularly from 0. 1 to 1 00 /yg/dose. The single or specific oligomeric envelope proteins may also serve as vaccine carriers to present homologous (e.g. T cell epitopes or B cell epitopes from the core, NS2, NS3, NS4 or NS5 regions) or heterologous (non-HCV) haptens, in the same manner as Hepatitis B surface antigen (see European Patent Application 1 74,444). In this use, envelope proteins provide an immunogenic carrier capable of stimulating an immune response to haptens or antigens conjugated to the aggregate. The antigen may be conjugated either by conventional chemical methods, or may be cloned into the gene encoding E 1 and/or E2 at a location corresponding to a hydrophi c region of the protein. Such hydrophyiic regions include the V 1 region (encompassing ammo acid positions 1 91 to 202), the V2 region (encompassing ammo acid positions 21 3 to 223), the V3 region (encompassing ammo acid positions 230 to 242), the V4 region (encompassing ammo acid positions 230 to 242), the V5 region (encompassing ammo acid positions 294 to 303) and the V6 region (encompassing amino acid positions 329 to 336). Another useful location for insertion of haptens is the hydrophobic region (encompassing approximately amino acid positions 264 to 293). It is shown in the present invention that this region can be deleted without affecting the reactivity of the deleted E 1 protein with antisera. Therefore, haptens may be inserted at the site of the deletion. The immunogenic compositions are conventionally administered parenterally, typically by injection, for example, subcutaneously or intramuscularly. Additional formulations suitable for other methods of administration include oral formulations and suppositories. Dosage treatment may be a single dose schedule or a multiple dose schedule. The vaccine may be administered in conjunction with other immunoregulatory agents. The present invention also relates to a composition comprising peptides or polypeptides as described above, for in vitro detection of HCV antibodies present in a biological sample. The present invention also relates to the use of a composition as described above for the preparation of an immunoassay kit for detecting HCV antibodies present in a biological sample. The present invention also relates to a method for in vitro diagnosis of HCV antibodies present in a biological sample, comprising at least the following steps : (i) contacting said biological sample with a composition comprising any of the envelope peptide or proteins as defined above, preferably in an immobilized form under appropriate conditions which allow the formation of an immune complex, wherein said peptide or protein can be a biotmylated peptide or protein which is covalently bound to a solid substrate by means of streptavidm or avidm complexes, (n) removing unbound components, (in) incubating the immune complexes formed with heterologous antibodies, with said heterologous antibodies having conjugated to a detectable label under appropriate conditions, (iv) detecting the presence of said immune complexes visually or mechanically (e.g. by means of densitometry, fluoπmetry, coloπmetry) Alternatively, the present invention also relates to competition immunoassay formats in which recombinantly produced purified single or specific oligomeric protein E1 and/or E2 and/or E1 /E2 proteins as disclosed above are used in combination with E 1 and/or E2 peptides in order to compete for HCV antibodies present in a biological sample. The present invention also relates to a kit for determining the presence of HCV antibodies, in a biological sample, comprising : - at least one peptide or protein composition as defined above, possibly in combination with other polypeptides or peptides from HCV or other types of HCV, with said peptides or proteins being preferentially immobilized on a solid substrate, more preferably on different microwells of the same ELISA plate, and even more preferentially on one and the same membrane strip, a buffer or components necessary for producing the buffer enabling binding reaction between these polypeptides or peptides and the antibodies against HCV present in the biological sample, means for detecting the immune complexes formed in the preceding binding reaction, possibly also including an automated scanning and interpretation device for inferring the HCV genotypes present in the sample from the observed binding pattern. The immunoassay methods according to the present invention utilize single or specific oligomeric antigens from the E 1 and or E2 domains that maintain linear (in case of peptides) and conformational epitopes (single or specific oligomeric proteins) recognized by antibodies in the sera from individuals infected with HCV It is within the scope of the invention to use for instance single or specific oligomeric antigens, dimeπc antigens, as well as combinations of single or specific oligomeric antigens The HCV E 1 and E2 antigens of the present invention may be employed in virtually any assay format that employs a known antigen to detect antibodies Of course, a format that denatures the HCV conformational epitope should be avoided or adapted A common feature of all of these assays is that the antigen is contacted with the body component suspected of containing HCV antibodies under conditions that permit the antigen to bind to any such antibody present in the component. Such conditions will typically be physiologic temperature, pH and ionic strenght using an excess of antigen The incubation of the antigen with the specimen is followed by detection of immune complexes comprised of the antigen. Design of the immunoassays is subject to a great deal of variation, and many formats are known in the art. Protocols may, for example, use solid supports, or immunoprecipitation. Most assays involve the use of labeled antibody or polypeptide, the labels may be, for example, enzymatic, fluorescent, chemilummescent, radioactive, or dye molecules. Assays which amplify the signals from the immune complex are also known; examples of which are assays which utilize biotm and avid or streptavidm, and enzyme-labeled and mediated immunoassays, such as ELISA assays The immunoassay may be, without limitation, in a heterogeneous or in a homogeneous format, and of a standard or competitive type. In a heterogeneous format, the polypeptide is typically bound to a solid matrix or support to facilitate separation of the sample from the polypeptide after incubation. Examples of solid supports that can be used are nitrocellulose (e.g., in membrane or microtiter well form), polyvinyl chloride (e g., in sheets or microtiter wells), polystyrene latex (e.g., in beads or microtiter plates, polyviny dine fluoride (known as Immunolon™), diazotized paper, nylon membranes, activated beads, and Protein A beads. For example, Dynatech Immunolon™ 1 or Immunlon™ 2 microtiter plates or 0.25 inch polystyrene beads (Precision Plastic Ball) can be used in the heterogeneous format. The solid support containing the antigenic polypeptides is typically washed after separating it from the test sample, and prior to detection of bound antibodies. Both standard and competitive formats are know in the art. In a homogeneous format, the test sample is incubated with the combination of antigens in solution. For example, it may be under conditions that will precipitate any antigen-antibody complexes which are formed Both standard and competitive formats for these assays are known in the art. In a standard format, the amount of HCV antibodies in the antibody-antigen complexes is directly monitored. This may be accomplished by determining whether labeled anti-xenogeneic (e.g. anti-human) antibodies which recognize an epitope on anti- HCV antibodies will bind due to complex formation. In a competitive format, the amount of HCV antibodies in the sample is deduced by monitoring the competitive effect on the Dinding of a known amount of labeled antibody (or other competing ligand) in the complex. Complexes formed comprising anti-HCV antibody (or in the case of competitive assays, the amount of competing antibody) are detected by any of a number of known techniques, depending on the format. For example, unlabeled HCV antibodies in the complex may be detected using a conjugate of anti-xenogeneic Ig complexed with a label (e.g. an enzyme label). In an immunoprecipitation or agglutination assay format the reaction between the HCV antigens and the antibody forms a network that precipitates from the solution or suspension and forms a visible layer or film of precipitate. If no anti-HCV antibody is present in the test specimen, no visible precipitate is formed. There currently exist three specific types of particle agglutination (PA) assays. These assays are used for the detection of antibodies to various antigens when coated to a support. One type of this assay is the hemagglutination assay using red blood cells (RBCs) that are sensitized by passively adsorbing antigen (or antibody) to the RBC. The addition of specific antigen antibodies present in the body component, if any, causes the RBCs coated with the purified antigen to agglutinate. To eliminate potential non-specific reactions in the hemagglutination assay, two artificial carriers may be used instead of RBC in the PA. The most common of these are latex particles. However, gelatin particles may also be used. The assays utilizing either of these carriers are based on passive agglutination of the particles coated with purified antigens. The HCV single or specififc oligomeric E 1 and/or E2 and/or E 1 /E2 antigens of the present invention comprised of conformational epitopes will typically be packaged in the form of a kit for use in these immunoassays. The kit will normally contain in separate containers the native HCV antigen, control antibody formulations (positive and/or negative), labeled antibody when the assay format requires the same and signal generating reagents (e.g. enzyme substrate) if the label does not generate a signal directly. The native HCV antigen may be already bound to a solid matrix or separate with reagents for binding it to the matrix. Instructions (e.g . written, tape, CD-ROM, etc. ) for carrying out the assay usually will be included in the kit. Immunoassays that utilize the native HCV antigen are useful in screening blood for the preparation of a supply from which potentially infective HCV is lacking. The method for the preparation of the blood supply comprises the following steps. Reacting a body component, preferably blood or a blood component, from the individual donating blood with HCV E 1 and/or E2 proteins of the present invention to allow an immunological reaction between HCV antibodies, if any, and the HCV antigen. Detecting whether anti-HCV antibody - HCV antigen complexes are formed as a result of the reacting. Blood contributed to the blood supDly is from donors that do not exhibit antibodies to the native HCV antigens, E 1 or £2. In cases of a positive reactivity to the HCV antigen, it is preferable to repeat the immunoassay to lessen the possibility of false positives. For example, in the large scale screening of blood for the production of blood products (e.g. blood transfusion, plasma, Factor VIII, immunoglobulin, etc.) 'screening' tests are typically formatted to increase sensitivity (to insure no contaminated blood passes) at the expense of specificity; i.e. the false-positive rate is increased. Thus, it is typical to only defer for further testing those donors who are 'repeatedly reactive' ; i.e. positive in two or more runs of the immunoassay on the donated sample. However, for confirmation of HCV-positivity, the 'confirmation' tests are typically formatted to increase specificity (to insure that no false-positive samples are confirmed) at the expense of sensitivity. Therefore the purification method described in the present invention for E1 and E2 will be very advantageous for including single or specific oligomeric envelope proteins into HCV diagnostic assays. The solid phase selected can include polymeric or glass beads, nitrocellulose, microparticles, microwells of a reaction tray, test tubes and magnetic beads. The signal generating compound can include an enzyme, a luminescent compound, a chromogen, a radioactive element and a chemiluminescent compound. Examples of enzymes include alkaline phosphatase, horseradish peroxidase and beta-galactosidase. Examples of enhancer compounds include biotin, anti-biotin and avidm. Examples of enhancer compounds binding members include biotin, anti-biotin and avidm In order to block tne e f fects of rheumatoid factor-like substances, the test sample is subjected to conditions sufficient to block the effect of rheumatoid factor-like substances These conditions comprise contacting the test sample with a quantity of anti-human IgG to form a mixture, and incubating the mixture for a time and under conditions sufficient to form a reaction mixture product substantially free of rheumatoid factor-like substance The present invention further contemplates the use of E 1 proteins, or parts thereof, more particularly HCV single or specific oligomeric E 1 proteins as defined above, for in vitro monitoring HCV disease or prognosing the response to treatment (for instance with Interferon) of patients suffering from HCV infection comprising incubating a biological sample from a patient with hepatitis C infection with an E1 protein or a suitable part thereof under conditions allowing the formation of an immunological complex, removing unbound components, - calculating the antι-E 1 titers present in said sample (for example at the start of and/or during the course of (interferon) therapy), monitoring the natural course of HCV disease, or prognosing the response to treatment of said patient on the basis of the amount antι-E 1 titers found in said sample at the start of treatment and/or during the course of treatment. Patients who show a decrease of 2, 3, 4, 5, 7, 1 0, 1 5, or preferably more than 20 times of the initial antι-E1 titers could be concluded to be long-term, sustained responders to HCV therapy, more particularly to interferon therapy. It is illustrated in the Examples section, that an antι-E1 assay may be very useful for prognosing long-term response to IFN treatment, or to treatment of Hepatitis C virus disease in general. More particularly the following E1 peptides as listed in Table 3 were found to be useful for in vitro monitoring HCV disease or prognosing the response to interferon treatment of patients suffering from HCV infection E 1 -31 (SEQ ID NO 56) spanning ammo acids 1 81 to 200 of the Core/E 1 V 1 region, E1 -33 (SEQ ID NO 57) spanning ammo acids 1 93 to 21 2 of the E 1 region, E 1 -35 (SEQ ID NO 58) spanning ammo acids 205 to 224 of the E1 V2 region (epitope B), E 1 -35A (SEQ ID NO 59) spanning ammo acids 208 to 227 of the E 1 V2 region (epitope B), 1 bE 1 (SEQ ID NO 53) spanning am o acids 1 92 to 228 of E 1 regions (V 1 C 1 and V2 regions (containing epitope B)), E 1 -51 (SEQ ID NO 66) spanning ammo acids 301 to 320 of the E 1 region, E 1 -53 (SEQ ID NO 67) spanning ammo acids 31 3 to 332 of the E 1 C4 region (epitope A), E 1 -55 (SEQ ID NO 68) spanning ammo acids 325 to 344 of the E 1 region It is to be understood that smaller fragments of the above-mentioned peptides also fall within the scope of the present invention Said smaller fragments can be easily prepared by chemical synthesis and can be tested for their ability to be used in an assay as detailed above and in the Examples section The present invention also relates to a kit for monitoring HCV disease or prognosing the response to treatment (for instance to interferon) of patients suffering from HCV infection comprising: - at least one E 1 protein or E1 peptide, more particularly an E 1 protein or E1 peptide as defined above, a buffer or components necessary for producing the buffer enabling the binding reaction between these proteins or peptides and the antι-E1 antibodies present in a biological sample, - means for detecting the immune complexes formed in the preceding binding reaction, possibly also an automated scanning and interpretation device for inferring a decrease of antι-E 1 titers during the progression of treatment It is to be understood that also E2 protein and peptides according to the present invention can be used to a certain degree to monitor/prognose HCV treatment as indicated above for the E 1 proteins or peptides because also the antι-E2 levels decrease in comparison to antibodies to the other HCV antigens It is to be understood, however, that it might be possible to determine certain epitopes in the E2 region which would also be suited for use in an test for monitoπng/prognosing HCV disease The present invention also relates to a serotypmg assay for detecting one or more serological types of HCV present in a biological sample, more particularly for detecting antibodies of the different types of HCV to be detected combined in one assay format, comprising at least the following steps • (i) contacting the biological sample to be analyzed for the presence of HCV antibodies of one or more serological types, with at least one of the E 1 and/or E2 and/or E 1 /E2 protein compositions or at least one of the E 1 or E2 peptide compositions as defined above, preferantially in an immobilized form under appropriate conditions which allow the formation of an immune complex, (ii) removing unbound components, (iii) incubating the immune complexes formed with heterologous antibodies, with said heterologous antibodies being conjugated to a detectable label under appropriate conditions, (iv) detecting the presence of said immune complexes visually or mechanically (e.g. by means of densitometry, fluoπmetry, coloπmetry) and inferring the presence of one or more HCV serological types present from the observed binding pattern. It is to be understood that the compositions of proteins or peptides used in this method are recombinantly expressed type-specific envelope proteins or type-specific peptides. The present invention further relates to a kit for serotypmg one or more serological types of HCV present in a biological sample, more particularly for detecting the antibodies to these serological types of HCV comprising: - at least one E1 and/or E2 and/or E 1 /E2 protein or E1 or E2 peptide, as defined above, a buffer or components necessary for producing the buffer enabling the binding reaction between these proteins or peptides and the anti-E 1 antibodies present in a biological sample, - means for detecting the immune complexes formed in the preceding binding reaction, possibly also an automated scanning and interpretation device for detecting the presence of one or more serological types present from the observed binding pattern. The present invention also relates to the use of a peptide or protein composition as defined above, for immobilization on a solid substrate and incorporation into a reversed phase hybridization assay, preferably for immobilization as parallel lines onto a solid support such as a membrane strip, for determining the presence or the genotype of HCV according to a method as defined above. Combination with other type-specific antigens from other HCV polyprotein regions also lies within the scope of the present invention. Figure and Table legends Figure 1 Restriction map of plasmid pgpt ATA 1 8 Figure 2 Restriction map of plasmid pgs ATA 1 8 Figure 3 Restriction map of plasmid pMS 66 Figure 4 Restriction map of plasmid pv HCV- 1 1 A Figure 5 Antι-E 1 levels in non-responders to IFN treatment Figure 6 Antι-E1 levels in responders to IFN treatment Figure 7 Anti-E l levels in patients with complete response to IFN treatment Figure 8 Antι-E 1 levels in incomplete responders to IFN treatment Figure 9 . Antι-E2 levels in non-responders to IFN treatment Figure 1 0 Antι-E2 levels in responders to IFN treatment Figure 1 1 Antι-E2 levels in incomplete responders to IFN treatment Figure 1 2 Antι-E2 levels in complete responders to IFN treatment Figure 1 3 Human antι-E 1 reactivity competed with peptides Figure 1 4 Competition of reactivity of antι-E 1 monoclonal antibodies with peptides Figure 1 5 Antι-E 1 (epitope 1 ) levels in non-responders to IFN treatment Figure 1 6 Antι-E 1 (epitope 1 ) levels in responders to IFN treatment Figure 1 7 Antι-E1 (epitope 2) levels in non-responders to IFN treatment Figure 1 8 Antι-E1 (epitope 2) levels in responders to IFN treatment Figure 1 9 Competition of reactivity of antι-E2 monoclonal antibodies with peptides Figure 20 Human antι-E2 reactivity competed with peptides Figure 21 Nucleic acid sequences of the present invention. The nucleic acid sequences encoding an E 1 or E2 protein according to the present invention may be translated (SEQ ID NO 3 to 1 3, 21 -31 , 35 and 41 -49 are translated in a reading frame starting from residue number 1 , SEQ ID NO 37-39 are translated in a reading frame starting from residue number 2), into the am o acid sequences of the respective E 1 or E2 proteins as shown in the sequence listing. Figure 22: ELISA results obtained from lentil lectm chromatography eluate fractions of 4 different E1 purifications of cell lysates infected with vvHCV39 (type 1 b), vvHCV40 (type 1 b), vvHCV62 (type 3a), and vvHCV63 (type 5a). Figure 23: Elution profiles obtained from the lentil lectm chromatography of the 4 different E 1 constructs on the basis of the values as shown in Figure 22. Figure 24: ELISA results obtained from fractions obtained after gelfiltration chromatography of 4 different E 1 purifications of cell lysates infected with vvHCV39 (type 1 b), vvHCV40 (type 1 b), vvHCV62 (type 3a), and vvHCV63 (type 5a). Figure 25: Profiles obtained from purifications of E 1 proteins of type 1 b ( 1 ), type 3a (2), and type 5a (3) (from RK 1 3 cells infected with vvHCV39, vvHCV62, and vvHCV63, respectively; purified on lentil lectm and reduced as in example 5.2 - 5.3) and a standard (4) The peaks indicated with ' 1 ', '2', and '3', represent pure E1 protein peaks (see Figure 24, E 1 reactivity mainly in fractions 26 to 30). Figure 26: Silver staining of an ΞDS-PAGE as described in example 4 of a raw lysate of E 1 vvHCV40 (type 1 b) (lane 1 ), pool 1 of the gelfiltration of vvHCV40 representing fractions 1 0 to 1 7 as shown in Figure 25 (lane 2), pool 2 of the gelfiltration of vvHCV40 representing fractions 1 8 to 25 as shown in Figure 25 (lane 3), and E 1 pool (fractions 26 to 30) (lane 4). Figure 27: Streptavidme-alkaline phosphatase blot of the fractions of the gelfiltration of E1 constructs 39 (type 1 b) and 62 (type 3a). The proteins were labelled with NEM-biotin. Lane 1 : start gelfiltration construct 39, lane 2 fraction 26 construct 39, lane 3: fraction 27 construct 39, lane 4 fraction 28 construct 39, lane 5: fraction 29 construct 39, lane 6 fraction 30 construct 39, lane 7 fraction 31 construct 39, lane 8 molecular weight marker, lane 9: start gelfiltration construct 62, lane 1 0 fraction 26 construct 62, lane 1 1 : fraction 27 construct 62, lane 1 2 fraction 28 construct 62, lane 1 3: fraction 29 construct 62, lane 1 4 fraction 30 construct 62, lane 1 5 : fraction 31 construct 62. Figure 28: Siver staining of an SDS-PAGE gel of the gelfiltration fractions of vvHCV- 39 (E1 s, type 1 b) and vvHCV-62 (E 1 s, type 3a) run under identical conditions as Figure 26. Lane 1 : start gelfiltration construct 39, lane 2 fraction 26 construct 39, lane 3: fraction 27 construct 39, lane 4 fraction 28 construct 39, lane 5: fraction 29 construct 39, lane 6 fraction 30 construct 39, lane 7 fraction 31 construct 39, lane 8 molecular weight marker, lane 9: start gelfiltration construct 62, lane 1 0 fraction 26 construct 62, lane 1 1 : fraction 27 construct 62, lane 1 2 fraction 28 construct 62, lane 1 3: fraction 29 construct 62, lane 1 4 fraction 30 construct 62, lane 1 5 fraction 31 construct 62 Figure 29 Western Blot analysis with antι-E 1 mouse monoclonal antibody 5E 1 A 1 0 giving a complete overview of the purification procedure Lane 1 crude lysate, Lane 2 flow through of lentil chromagtography, Lane 3 wash with Empigen BB after lentil chromatography, Lane 4 Eluate of lentil chromatography, Lane 5 - Flow through during concentration of the lentil eluate, Lane 6 Pool of E 1 after Size Exclusion Chromatography (gelfiltration). Figure 30 OD 280 profile (continuous line) of the lentil lectm chromatography of E2 protein from RK 1 3 cells infected with vvHCV44 The dotted line represents the E2 reactivity as detected by ELISA (as in example 6) Figure 31 A. OD 280 profile (continuous line) of the lentil-lectin gelfiltration chromatography E2 protein pool from R 1 3 cells infected with vvHCV44 in which the E2 pool is applied immediately on the gelfiltration column (non-reduced conditions) The dotted line represents the E2 reactivity as detected by ELISA (as in example 6). Figure 31 B. OD 280 profile (continuous line) of the lentil-lectin gelfiltration chromatography E2 protein pool from RK 1 3 cells infected with vvHCV44 in which the E2 pool was reduced and blocked according to Example 5.3 (reduced conditions). The dotted line represents the E2 reactivity as detected by ELISA (as in example 6). Figure 32 Nι 2 + -IMAC chromatography and ELISA reactivity of the E2 protein as expressed from vvHCV44 after gelfiltration under reducing conditions as shown in Figure 31 B. Figure 33: Silver staining of an SDS-PAGE of 0.5 /yg of purified E2 protein recovered by a 200 mM imidazole elution step (lane 2) and a 30mM imidazole wash (lane 1 ) of the Nι 2+ -IMAC chromatography as shown in Figure 32. Figure 34: OD profiles of a desalting step of the purified E2 protein recovered by 200 mM immidazole as shown in Figure 33, intended to remove imidazole. Figure 35A: Antibody levels to the different HCV antigens (Core 1 , Core 2, E2HCVR, NS3) for NR and LTR followed during treatment and over a period of 6 to 1 2 months after treatment determined by means of the LIAscan method. The average values are indicated by the curves with the open squares Figure 35B: Antibody levels to the different HCV antigens (NS4, NS 5 , E 1 and E2) for NR and LTR followed during treatment and over a period of 6 to 1 2 months after treatment determined by means of the LIAscan method . The avergae vallues are indicated by the curve with the open squares Figure 36: Average E 1 antibody (E1 Ab) and E2 antibody (E2Ab) levels in the LTR and NR groups. Figure 37 : Averages E 1 antibody (E1 Ab) levels for non-responders (NR) and long term responders (LTR) for type 1 b and type 3a Figure 38: Relative map positions of the antι-E2 monoclonal antibodies Figure 39: Partial deglycosylation of HCV E 1 envelope protein The lysate of vvHCVI OA-infected RK 1 3 cells were incubated with different concentrations of glycosidases according to the manufacturer's instructions. Right panel: Glycopeptidase F (PNGase F) . Left panel Endoglycosidase H (Endo H). Figure 40: Partial deglycosylation of HCV E2 envelope proteins. The lysate of vvHCV64-ιnfected (E2) and vvHCV41 -infected (E2s)RK 1 3 cells were incubated with different concentrations of Glycopeptidase F (PNGase F) according to the manufacturer's instructions. Figure 41 : In vitro mutagenesis of HCV E1 glycoprotems. Map of the mutated sequences and the creation of new restriction sites. Figure 42A: In vitro mutagenesis of HCV E1 glycoprotein (part 1 ) . First step of PCR amplification. Figure 42B: In vitro mutagensis of HCV E 1 glycoprotein (part 2). Overlap extension and nested PCR. Figure 43: In vitro mutagesesis of HCV E 1 glycoprotems. Map of the PCR mutated fragments (GLY-# and OVR-#) synthesized during the first step of amplification. Figure 44A: Analysis of E 1 glycoprotein mutants by Western blot expressed in HeLa (left) and RK1 3 (right) cells. Lane 1 : wild type VV (vaccinia virus), Lane 2: original E1 protein (vvHCV-1 0A), Lane 3: E 1 mutant Gly- 1 (vvHCV-81 ), Lane 4: E 1 mutant Gly-2 (vvHCV-82), Lane 5: E 1 mutant Glv-3 (vvHCV- 83), Lane 6: E1 mutant Gly-4 (vvHCV-84), Lane 7: E 1 mutant Gly-5 (vvHCV-85), Lane 8: E 1 mutant Gly-6 (vvHCV-86). Figure 44B: Analysis of E1 glycosylation mutant vaccinia viruses by PCR amplification/restriction. Lane 1: E1 (vvHCV-10A), BspE I, Lane 2 E1.GLY-1 (vvHCV-81), BspE I, Lane 4: E1 (vvHCV-IOA), Sac I, Lane 5 E1.GLY-2 (vvHCV-82), Sac I, Lane 7: E1 (vvHCV-10A), Sac I, Lane 8 E1.GLY-3 (vvHCV-83), Sac I, Lane 10: E1 (vvHCV-10A), Stu I, Lane 11 E1.GLY-4(vvHCV-84), Stu I, Lane 13: E1 (vvHCV-10A), Sma I, Lane 14 E1.GLY-5 (vvHCV-85), Sma I, Lane 16: E1 (vvHCV-10A), Stu I, Lane 17 E1.GLY-6 (vvHCV-86), Stu I, Lane 3 - 6 - 9 - 12 - 15 : Low Molecular Weight Marker, pBluescπpt SK + , Msp I. Figure 45: SDS polyacrylamide gel electrophoresis of recombinant E2 expressed in S. cerevisiae. Innoculates were grown in leucine selective medium for 72 hrs. and diluted 1/15 in complete medium. After 10 days of culture at 28°C, medium samples were taken. The equivalent of 200 μ\ of culture supernatant concentrated by speedvac was loaded on the gel. Two independent transformants were analysed. Figure 46: SDS polyacrylamide gel electrophoresis of recombinant E2 expressed in a glycosylation deficient S. cerevisiae mutant. Innoculae were grown in leucine selective medium for 72 hrs. and diluted 1/15 in complete medium. After 10 days of culture at 28°C, medium samples were taken. The equivalent of 350 μ\ of culture supernatant, concentrated by ion exchange chromatography, was loaded on the gel. Table 1 Features of the respective clones and primers used for amplification for constructing the different forms of the E1 protein as despected in Example 1. Table 2 Summary of Anti-E1 tests Table 3 Synthetic peptides for competition studies Table 4 Changes of envelope antibody levels over time. Table 5 Difference between LTR and NR Table 6 Competition experiments between murine E2 monoclonal antibodies Table 7 Primers for construction of E1 glycosylation mutants Table 8 Analysis of E1 glycosylation mutants by ELISA Example 1 : Cloning and expression of the hepatitis C virus El protein 1 Construction of vaccinia virus recombination vectors The pgptATAI 8 vaccinia recombination plasmid is a modified version of pATA I 8 (Stunnenberg et al, 1 988) with an additional insertion containing the E coli xanth e guanme phosphoπbosyl transferase gene under the control of the vaccinia virus 13 intermediate promoter (Figure 1 ). The plasmid pgsATA I 8 was constructed by inserting an oligonucleotide linker with SEQ ID NO 1 /94, containing stop codons in the three reading frames, into the Pst I and Hindlll-cut pATA I 8 vector This created an extra Pac I restriction site (Figure 2). The original Hind 111 site was not restored Oligonucleotide linker with SEQ ID NO 1 /94 5 ' G GCATGC AAGCTT AATTAATT 3 ' 3 ' ACGTC CGTACG TTCGAA TTAATTAA TCGA 5 ' Ps t I SphI Hi ndl l l Pac I ( Hmdl l l ) In order to facilitate rapid and efficient purification by means of Nι 2+ chelation of engineered histidine stretches fused to the recombinant proteins, the vaccinia recombination vector pMS66 was designed to express secreted proteins with an additional carboxy-termmal histidine tag. An oligonucleotide linker with SEQ ID NO 2/95, containing unique sites for 3 restriction enzymes generating blunt ends (Sma I, Stu I and Pml l/Bbr PI) was synthesized in such a way that the carboxy-termmal end of any cDNA could be inserted in frame with a sequence encoding the protease factor Xa cleavage site followed by a nucleotide sequence encoding 6 histidmes and 2 stop codons (a new Pac I restriction site was also created downstream the 3'end) This oligonucleotide with SEQ ID NO 2/95 was introduced between the Xma I and Pst I sites of pgptATAI 8 (Figure 3). Oligonucleotide linker with SEQ ID NO 2/95: ' 5 ' CCGGG GAGGCCTGCACGTGATCGAGGGCAGACACCATCACCACCATCACTAATAGTTAATTAA CTGCAJ 3' C CTCCGGACGTGCACTAGCTCCCGTCTGTGGTAGTGGTGGTAGTGATTATCAATTAATT G Xrπal PstI Example 2. Construction of HCV recombinant plasmids 2. 1 . Constructs encoding different forms of the E 1 protein Polymerase Chain Reaction (PCR) products were derived from the serum samples by RNA preparation and subsequent reverse-transcription and PCR as described previously (Stuyver et al., 1 993b) . Table 1 shows the features of the respective clones and the primers used for amplification. The PCR fragments were cloned into the Sma l-cut pSP72 (Promega) plasmids. The following clones were selected for insertion into vaccinia reombmation vectors: HCCI9A (SEQ ID NO 3), HCCI 1 0A (SEQ ID NO 5), HCCI 1 1 A (SEQ ID NO 7), HCCI 1 2A (SEQ ID NO 9), HCCI 1 3A (SEQ ID NO 1 1 ), and HCCI1 7A (SEQ ID NO 1 3) as depicted in Figure 21 . cDNA fragments containing the E1 - coding regions were cleaved by EcoRI and Hindi 11 restriction from the respective pSP72 plasmids and inserted into the EcoRI/Hindlll-cut pgptATA-1 8 vaccinia recombination vector (described in example 1 ), downstream of the 1 1 K vaccinia virus late promoter. The respective plasmids were designated pvHCV-9 A, pvHCV-1 0A, pvHCV- 1 1 A, pvHCV- 1 2A, pvHCV- 1 3A and pvHCV-1 7A, of which pvHCV-1 1 A is shown in Figure 4. 2.2. Hydrophobic region El deletion mutants Clone HCCI37, containing a deletion of codons Asp264 to Val287 (nucleotides 790 to 861 , region encoding hydrophobic domain I) was generated as follows: 2 PCR fragments were generated from clone HCCI 1 0A with primer sets HCPr52 (SEQ ID NO 1 6)/HCPr1 07 (SEQ ID NO 1 9) and HCPrl 08 (SEQ ID NO 20)/HCPR54 (SEQ ID NO 1 8). These primers are shown in Figure 21 . The two PCR fragments were purified from agarose gel after electrophoresis and 1 ng of each fragment was used together as template for PCR by means of primers HCPr52 (SEQ ID NO 1 6) and HCPr54 (SEQ ID NO 1 8). The resulting fragment was cloned into the Sma l-cut pSP72 vector and clones containing the deletion were readily identified because of the deletion of 24 codons (72 base pairs). Plasmid pSP72HCCI37 containing clone HCCI37 (SEQ ID 1 5) was selected. A recombinant vaccinia plasmid containing the full-length E 1 cDNA lacking hydrophobic domain I was constructed by inserting the HCV sequence surrounding the deletion (fragment cleaved by Xma I and BamH I from the vector pSP72-HCCI37) into the Xma l-Bam H I sites of the vaccinia plasmid pvHCV-1 0A. The resulting plasmid was named pvHCV-37. After confirmatory sequencing, the ammo-terminal region containing the internal deletion was isolated from this vector pvHCV-37 (cleavage by EcoR I and BstE I I) and reinserted into the Eco Rl and Bst El l-cut pvHCV- 1 1 A plasmid This construct was expected to express an E 1 protein with both hydrophobic domains deleted and was named pvHCV-38. The E1 -codιng region of clone HCCI38 is represented by SEQ ID NO 23. As the hydrophilic region at the E 1 carboxyterminus (theoretically extending to around ammo acids 337-340) was not completely included in construct pvHCV-38, a larger E 1 region lacking hydrophobic domain I was isolated from the pvHCV-37 plasmid by EcoR I/Bam HI cleavage and cloned into an EcoRI/BamHI-cut pgsATA-1 8 vector. The resulting plasmid was named pvHCV-39 and contained clone HCCI39 (SEQ ID NO 25) . The same fragment was cleaved from the pvHCV-37 vector by BamH I (of which the sticky ends were filled with Klenow DNA Polymerase I (Boehπnger)) and subsequently by EcoR I (5' cohesive end). This sequence was inserted into the EcoRI and Bbr Pl-cut vector pMS-66. This resulted in clone HCCI40 (SEQ ID NO 27) in plasmid pvHCV-40, containing a 6 histidine tail at its carboxy-termmal end. 2.3. E 1 of other genotypes Clone HCCI62 (SEQ ID NO 29) was derived from a type 3a-ιnfected patient with chronic hepatitis C (serum BR36, clone BR36-9- 1 3, SEQ ID NO 1 9 in WO 94/25601 , and see also Stuyver et al. 1 993a) and HCCI63 (SEQ ID NO 31 ) was derived from a type 5a-ιnfected child with post-transfusion hepatitis (serum BE95, clone PC-4- 1 , SEQ ID NO 45 in WO 94/25601 ). 2.4. E2 constructs The HCV E2 PCR fragment 22 was obtained from serum BE 1 1 (genotype 1 b) by means of primers HCPr1 09 (SEQ ID NO 33) and HCPr72 (SEQ ID NO 34) using techniques of RNA preparation, reverse-transcription and PCR, as described in Stuyver et al., 1 993b, and the fragment was cloned into the Sma l-cut pSP72 vector. Clone HCCI22A (SEQ ID NO 35) was cut with Ncol/AlwNI or by BamHI/AlwNI and the sticky ends of the fragments were blunted (Ncol and BamHI sites with Klenow DNA Polymerase I (Boehπnger), and AlwNI with T4 DNA polymerase (Boehπnger)) . The BamHI/AlwNI cDNA fragment was then inserted into the vaccinia pgsATA- 1 8 vector that had been linearized by EcoR I and Hind II I cleavage and of which the cohesive ends had been filled with Klenow DNA Polymerase (Boehrmger) The resulting plasmid was named pvHCV-41 and encoded the E2 region from ammo acids Met347 to Gln673, including 37 ammo acids (from Met347 to Gly383) of the E 1 protein that can serve as signal sequence The same HCV cDNA was inserted into the EcoR I and Bbr Pl-cut vector pMS66, that had subsequently been blunt ended with Klenow DNA Polymerase The resulting plasmid was named pvHCV-42 and also encoded ammo acids 347 to 683 The Ncol/AlwNI fragment was inserted in a similar way into the same sites of pgsATA- 1 8 (pvHCV-43) or pMS-66 vaccinia vectors (pvHCV-44) pvHCV-43 and pvHCV-44 encoded am o acids 364 to 673 of the HCV polyprotein, of which ammo acids 364 to 383 were derived from the natural carboxytermmal region of the E 1 protein encoding the signal sequence for E2, and ammo acids 384 to 673 of the mature E2 protein. 2 5. Generation of recombinant HCV-vaccinia viruses Rabbit kidney RK 1 3 cells (ATCC CCL 37), human osteosarcoma 1 43B thymidme kinase deficient (TK ) (ATCC CRL 8303), HeLa (ATCC CCL 2), and Hep G2 (ATCC HB 8065) cell lines were obtained from the American Type Culture Collection (ATCC, Rockville, Md, USA). The cells were grown in Dulbecco's modified Eagle medium (DMEM) supplemented with 1 0 % foetal calf serum, and with Earle's salts (EMEM) for RK 1 3 and 143 B (TK-), and with glucose (4 g/l) for Hep G2. The vaccinia virus WR strain (Western Reserve, ATTC VR1 1 9) was routinely propagated in either 143B or RK 1 3 cells, as described previously (Panicali & Paoletti, 1 982; Piccmi et al., 1 987, Mackett et al., 1 982, 1 984, and 1 986). A confluent monolayer of 1 43B cells was infected with wild type vaccinia virus at a multiplicity of infection (m.o.i.) of 0.1 ( = 0.1 plaque forming unit (PFU) per cell). Two hours later, the vaccinia recombination plasmid was transfected into the infected cells in the form of a calcium phosphate coprecipitate containing 500 ng of the plasmid DNA to allow homologous recombination (Graham & van der Eb, 1 973; Mackett et al., 1 985). Recombinant viruses expressing the Escheπchia coli xanthine-quanine phosphoπbosyl transferase (gpt) protein were selected on rabbit kidney RK 1 3 cells incubated in selection medium (EMEM containing 25 / y g/ml mycopheno c acid (MPA), 250 /yg/ml xanthine, and 1 5 yg/ml hypoxanthine; Falkner and Moss, 1 988; Janknecht et al, 1 991 ). Single recombinant viruses were purified on fresh monolayers of RK 1 3 cells under a 0.9 % agarose overlay in selection medium Thymidine kmase deficient (TK ) recombinant viruses were selected and then plaque purified on fresh monolayers of human 143B cells (TK-) in the presence of 25 yg/ml 5-bromo-2'- deoxyuridine. Stocks of purified recombinant HCV-vaccmia viruses were prepared by infecting either human 143 B or rabbit RK 1 3 cells at an m .o.i . of 0.05 (Mackett et al, 1 988). The insertion of the HCV cDNA fragment in the recombinant vaccinia viruses was confirmed on an aliquot (50 μ\) of the cell lysate after the MPA selection by means of PCR with the primers used to clone the respective HCV fragments (see Table 1 ). The recombinant vaccinia-HCV viruses were named according to the vaccinia recombination plasmid number, e.g. the recombinant vaccinia virus vvHCV-1 0A was derived from recombining the wild type WR strain with the pvHCV- 1 0A plasmid . Example 3: infection of cells with recombinant vaccinia viruses A confluent monolayer of RK 1 3 cells was infected at a .o.i. of 3 with the recombinant HCV-vaccinia viruses as described in example 2 . For infection, the cell monolayer was washed twice with phosphate-buffered saline pH 7.4 (PBS) and the recombinant vaccinia virus stock was diluted in MEM medium. Two hundred μ\ of the virus solution was added per 1 0 6 cells such that the m.o.i. was 3, and incubated for 45 mm at 24 ° C. The virus solution was aspirated and 2 ml of complete growth medium (see example 2) was added per 1 0 6 cells. The cells were incubated for 24 hr at 37 °C during which expression of the HCV proteins took place. Example 4: Analysis of recombinant proteins by means of western blotting The infected cells were washed two times with PBS, directly lysed with lysis buffer (50 mM Tris.HCI pH 7.5, 1 50 mM NaCl, 1 % Triton X-1 00, 5 mM MgCI 2 , 1 / y g/ml aprotinin (Sigma, Bornem, Belgium)) or detached from the flasks by incubation in 50 mM Tris.HCL pH 7.5/ 1 0 mM EDTA/ 1 50 mM NaCl for 5 m , and collected by centrifugation (5 min at 1 000g). The cell pellet was then resuspended in 200 μ\ lysis buffer (50 M Tris.HCL pH 8.0, 2 mM EDTA, 1 50 mM NaCl, 5 mM MgCI 2 aprotinin, 1 % Triton X-1 00) per 1 0 6 cells. The cell lysates were cleared for 5 mm at 1 4,000 rpm in an Eppendorf centrifuge to remove the insoluble debris. Proteins of 20 A I lysate were separated by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) . The proteins were then electro-transferred from the gel to a nitrocellulose sheet (Amersham) using a Hoefer HSI transfer unit cooled to 4 ° C for 2 hr at 1 00 V constant voltage, in transfer buffer (25 mM Tπs.HCI pH 8.0, 1 92 mM glycine, 20% (v/v) methanol) . Nitrocellulose filters were blocked with Blotto (5 % (w/v) fat-free instant milk powder in PBS; Johnson et al., 1 981 ) and incubated with primary antibodies diluted in Blotto/0.1 % Tween 20. Usually, a human negative control serum or serum of a patient infected with HCV were 200 times diluted and premcubated for 1 hour at room temperature with 200 times diluted wild type vaccinia virus-infected cell lysate in order to decrease the non-specific binding. After washing with Blotto/0. 1 % Tween 20, the nitrocellulose filters were incubated with alkaline phosphatase substrate solution diluted in Blotto/0.1 % Tween 20. After washing with 0.1 % Tween 20 in PBS, the filters were incubated with alkaline phosphatase substrate solution ( 1 00 mM Tπs. HCI pH 9.5, 1 00 mM NaCl, 5 mM MgCI 2 , 0, 38 /yg/ml nitroblue tetrazolium, 0. 1 65 / y g/ml 5-bromo-4-chloro-3-ιndolylphosphate). All steps, except the electrotransfer, were performed at room temperature. Example 5: Purification of recombinant E1 or E2 protein 5.1 . Lvsis Infected RK 1 3 cells (carrying E1 or E2 constructs) were washed 2 times with phosphate-buffered saline (PBS) and detached from the culture recipients by incubation in PBS containing 1 0 mM EDTA. The detached cells were washed twice with PBS and 1 ml of lysis buffer (50 mM Tris.HCI pH 7.5, 1 50 mM NaCl, 1 % Triton X- 1 00, 5 mM MgCI 2 , 1 /yg/ml aprotinin (Sigma, Bornem, Belgium) containing 2 mM biotinylated N- ethylmaleimide (biotin-NEM) (Sigma) was added per 1 0 E cells at 4 ° C. This lysate was homogenized with a type B douncer and left at room temperature for 0.5 hours. Another 5 volumes of lysis buffer containing 1 0 mM N-ethylmaleimide (NEM, Aldπch, Bornem, Belgium) was added to the primary lysate and the mixture was left at room temperature for 1 5 min. Insoluble cell debris was cleared from the solution by centrifugation in a Beckman JA-14 rotor at 1 4,000 rpm (301 00 g at r may ) for 1 hour at 4 ° C. 5.2. Lectm Chromatography The cleared cell lysate was loaded at a rate of 1 ml 'min on a 0.8 by 1 0 cm Lentil- lectin Sepharose 4B column (Pharmacia) that had been equilibrated with 5 column volumes of lysis buffer at a rate of 1 ml/mm. The lentil-lectin column was washed with 5 to 1 0 column volumes of buffer 1 (0.1 M potassium phosphate pH 7.3, 500 mM KCI, 5 % glycerol, 1 mM 6-NH 2 -hexanoιc acid, 1 mM MgCI 2 , and 1 % DecylPEG (KWANT, Bedum, The Netherlands). In some experiments, the column was subsequently washed with 1 0 column volumes of buffer 1 containing 0.5 % Empigen-BB (Calbiochem, San Diego, CA, USA) instead of 1 % DecylPEG . The bound material was eluted by applying elution buffer ( 1 0 mM potassium phosphate pH 7.3, 5 % glycerol, 1 mM hexanoic acid, 1 mM MgCI 2 , 0.5 % Empigen-BB, and 0.5 M σ-methyl-mannopyranoside) . The eluted material was fractionated and fractions were screened for the presence of E 1 or E2 protein by means of ELISA as described in example 6. Figure 22 shows ELISA results obtained from lentil lect eluate fractions of 4 different E 1 purifications of cell lysates infected with vvHCV39 (type 1 b), vvHCV40 (type 1 b), vvHCV62 (type 3a), and vvHCV63 (type 5a). Figure 23 shows the profiles obtained from the values shown in Figure 22. These results show that the lect affinity column can be employed for envelope proteins of the different types of HCV. 5.3. Concentration and partial reduction The E 1 - or E2-posιtιve fractions were pooled and concentrated on a Centπcon 30 kDa (Amicon) by centrifugation for 3 hours at 5,000 rpm in a Beckman JA-20 rotor at 4 ° C. In some experiments the E1 - or E2-posιtive fractions were pooled and concentrated by nitrogen evaporation. An equivalent of 3.1 0 s cells was concentrated to approximately 200 μ\. For partial reduction, 30% Empigen-BB (Calbiochem, San Diego, CA, USA) was added to this 200 μ\ to a final concentration of 3.5 %, and 1 M DTT in H 2 0 was subsequently added to a final concentration of 1 .5 to 7.5 mM and incubated for 30 min at 37 ° C. NEM ( 1 M in dimethylsulphoxide) was subsequently added to a final concentration of 50 mM and left to react for another 30 mm at 37 ° C to block the free sulphydryl groups. 5.4 Gel filtration chromatography A Superdex-200 HR 1 0/20 column (Pharmacia) was equilibrated with 3 column volumes PBS/3 % Empigen-BB. The reduced mixture was injected in a 500 μ\ sample loop of the Smart System (Pharmacia) and PBS/3 % Empigen-BB buffer was added for gelfiltration. Fractions of 250 μ\ were collected from V = to V.. The fractions were screened for the presence of E 1 or E2 protein as described m example 6. Figure 24 shows ELISA results obtained from fractions obtained after gelfiltration chromatography of 4 different E 1 purifications of cell lysates infected with vvHCV39 (type 1 b), vvHCV40 (type 1 b), vvHCV62 (type 3a), and vvHCV63 (type 5a) . Figure 25 shows the profiles obtained from purifications of E 1 proteins of types 1 b, 3a, and 5a (from RK 1 3 cells infected with vvHCV39, vvHCV62, and wHCV63, respectively; purified on lentil lectm and reduced as in the previous examples). The peaks indicated with ' 1 ', '2', and '3', represent pure E 1 protein peaks (E 1 reactivity mainly in fractions 26 to 30). These peaks show very similar molecular weights of approximately 70 kDa, corresponding to dimeric E 1 protein. Other peaks in the three profiles represent vaccinia virus and/or cellular proteins which could be separated from E 1 only because of the reduction step as outlined in example 5.3. and because of the subsequent gelfiltration step in the presence of the proper detergent. As shown in Figure 26 pool 1 (representing fractions 1 0 to 1 7) and pool 2 (representing fractions 1 8 to 25) contain contaminating proteins not present in the E 1 pool (fractions 26 to 30) . The E 1 peak fractions were ran on SDS/PAGE and blotted as described in example 4. Proteins labelled with NEM-biotin were detected by streptavidm-alkaline phosphatase as shown in Figure 27. It can be readily observed that, amongst others, the 29 kDa and 45kDa contaminating proteins present before the gelfiltration chromatography (lane 1 ) are only present at very low levels in the fractions 26 to 30. The band at approximately 65kDa represents the E1 dimeric form that could not be entirely disrupted into the monomeric E1 form. Similar results were obtained for the type 3a E 1 protein (lanes 1 0 to 1 5), which shows a faster mobility on SDS/PAGE because of the presence of only 5 carbohydrates instead of 6. Figure 28 shows a silver stain of an SDS/PAGE gel run in identical conditions as in Figure 26. A complete overview of the purification procedure is given in Figure 29. The presence of purified E 1 protein was further confirmed by means of western blotting as described in example 4. The dimeric E 1 protein appeared to be non- aggregated and free of contaminants The subtype 1 b E 1 protein purified from vvHCV40-ιnfected cells according to the above scheme was aminoterminally sequenced on an 477 Perkins-Elmer sequencer and appeared to contain a tyrosine as first residue This confirmed that the E 1 protein had been cleaved by the signal peptidase at the correct position (between A 1 91 and Y 1 92) from its signal sequence This confirms the finding of Hijikata et al ( 1 991 ) that the aminoterminus of the mature E 1 protein starts at ammo acid position 1 92 5 5 Purification of the E2 protein The E2 protein (ammo acids 384 to 673) was purified from RK 1 3 cells infected with vvHCV44 as indicated in Examples 5 1 to 5 4 Figure 30 shows the OD 2S0 profile (continuous line) of the lentil lectm chromatography The dotted line represents the E2 reactivity as detected by ELISA (see example 6) Figure 31 shows the same profiles obtained from gelfiltration chromatography of the lentil-lectin E2 pool (see Figure 30), part of which was reduced and blocked according to the methods as set out in example 5.3 , and part of which was immediately applied to the column Both parts of the E2 pool were run on separate gelfiltration columns It could be demonstrated that E2 forms covalently- nked aggregates with contaminating proteins if no reduction has been performed. After reduction and blocking, the majority of contaminating proteins segregated into the V 0 fraction. Other contaminating proteins copuπfied with the E2 protein, were not covalently linked to the E2 protein any more because these contaminants could be removed in a subsequent step Figure 32 shows an additional Nι 2 + -IMAC purification step carried out for the E2 protein purification This affinity purification step employs the 6 histidine residues added to the E2 protein as expressed from vvHCV44 Contaminating proteins either run through the column or can be removed by a 30 M imidazole wash Figure 33 shows a silver-stained SDS/PAGE of 0.5 μg of purified E2 protein and a 30 mM imidazole wash The pure E2 protein could be easily recovered by a 200 mM imidazole elution step. Figure 34 shows an additional desalting step intended to remove imidazole and to be able to switch to the desired buffer, e.g. PBS, carbonate buffer, saline. Starting from about 50,000 cm 2 of RK 1 3 cells infected with vvHCV 1 1 A (or vvHCV40) for the production of E 1 or vvHCV41 , vvHCV42, vvHCV43, or vvHCV44 for production of E2 protein, the procedures described in examples 5 1 to 5 5 allow the r iπfication of approximately 1 .3 mg of E 1 protein and 0.6 mg of E2 protein. It should also be remarked that secreted E2 protein (constituting approximately 30-40 %, 60-70% being in the mtracellular form) is chracteπzed by aggregate formation (contrary to expectations). The same problem is thus posed to purify secreted E2. The secreted E2 can be purified as disclosed above. Example 6: ELISA for the detection of anti-El or anti-E2 antibodies or for the detection of E1 or E2 proteins Maxisorb microwell plates (Nunc, Roskilde, Denmark) were coated with 1 volume (e.g. 50 /yl or 1 00 μ\ or 200 yl) per well of a 5 //g/ml solution of Streptavidm (Boehrmger Mannheim) in PBS for 1 6 hours at 4 ° C or for 1 hour at 37 ° C. Alternatively, the wells were coated with 1 volume of 5 /yg/ml of Galanthus niva s agglutinm (GNA) in 50 mM sodium carbonate buffer pH 9.6 for 1 6 hours at 4 ° C or for 1 hour at 37 ° C. In the case of coating with GNA, the plates were washed 2 times with 400 //I of Washing Solution of the Innotest HCV Ab III kit (Innogenetics, Zwijndrecht, Belgium). Unbound coating surfaces were blocked with 1 .5 to 2 volumes of blocking solution (0.1 % casein and 0.1 % NaN 3 in PBS) for 1 hour at 37 " C or for 1 6 hours at 4 ° C. Blocking solution was aspirated. Purified E1 or E2 was diluted to 1 00-1 000 ng/ml (concentration measured at A = 280 nm) or column fractions to be screened for E 1 or E2 (see example 5), or E 1 or E2 in non-purified cell lysates (example 5.1 .) were diluted 20 times in blocking solution, and 1 volume of the E1 or E2 solution was added to each well and incubated for 1 hour at 37 ° C on the Streptavidin- or GNA-coated plates. The microwells were washed 3 times with 1 volume of Washing Solution of the Innotest HCV Ab III kit (Innogenetics, Zwijndrecht, Belgium). Serum samples were diluted 20 times or monoclonal anti-E 1 or anti-E2 antibodies were diluted to a concentration of 20 ng/ml in Sample Diluent of the Innotest HCV Ab III kit and 1 volume of the solution was left to react with the E 1 or E2 protein for 1 hour at 37 ° C. The microwells were washed 5 times with 400 μ\ of Washing Solution of the Innotest HCV Ab III kit (Innogenetics, Zwijndrecht, Belgium). The bound antibodies were detected by incubating each well for 1 hour at 37 ° C with a goat anti-human or anti-mouse IgG, peroxidase-conjugated secondary antibody (DAKO, Glostrup, Denmark) diluted 1 /80,000 in 1 volume of Conjugate Diluent of the Innotest HCV Ab III kit (Innogenetics, Zwijndrecht, Belgium), and color development was obtained by addition of substrate of the Innotest HCV Ab III kit (Innogenetics, Zwijndrecht, Belgium) diluted 1 00 times in 1 volume of Substrate Solution of the Innotest HCV Ab I II kit (Innogenetics, Zwijndrecht, Belgium) for 30 mm at 24 ° C after washing of the plates 3 times with 400 μ\ of Washing Solution of the Innotest HCV Ab III kit (Innogenetics, Zwijndrecht, Belgium). Example 7: Follow up of patient groups with different clinical profiles 7. 1 . Monitoring of anti-E l and antι-E2 antibodies The current hepatitis C virus (HCV) diagnostic assays have been developed for screening and confirmation of the presence of HCV antibodies. Such assays do not seem to provide information useful for monitoring of treatment or for prognosis of the outcome of disease. However, as is the case for hepatitis B, detection and quantification of anti-envelope antibodies may prove more useful in a clinical setting. To investigate the possibility of the use of anti-E 1 antibody titer and antι-E2 antibody titer as prognostic markers for outcome of hepatitis C disease, a series of IFN-σ treated patients with long-term sustained response (defined as patients with normal transaminase levels and negative HCV-RNA test (PCR in the 5' non-coding region) in the blood for a period of at least 1 year after treatment) was compared with patients showing no response or showing biochemical response with relapse at the end of treatment. A group of 8 IFN-σ treated patients with long-term sustained response (LTR, follow up 1 to 3.5 years, 3 type 3a and 5 type 1 b) was compared with 9 patients showing non-complete responses to treatment (NR, follow up 1 to 4 years, 6 type 1 b and 3 type 3a). Type 1 b (vvHCV-39, see example 2.5.) and 3a E 1 (vvHCV-62, see example 2.5.) proteins were expressed by the vaccinia virus system (see examples 3 and 4) and purified to homogeneity (example 5). The samples derived from patients infected with a type 1 b hepatitis C virus were tested for reactivity with purified type 1 b E1 protein, while samples of a type 3a infection were tested for reactivity of anti-type 3a E 1 antibodies in an ELISA as desribed in example 6. The genotypes of hepatitis C viruses infecting the different patients were determined by means of the Inno-LiPA genotyping assay (Innogenetics, Zwijndrecht, Belgium). Figure 5 shows the anti-E 1 signal-to-noise ratios of these patients followed during the course of interferon treatment and during the follow-up period after treatment. LTR cases consistently showed rapidly declining antι-E 1 levels (with complete negativation in 3 cases), while antι-E 1 levels of NR cases remained approximately constant. Some of the obtained anti- E I data are shown in Table 2 as average S/N ratios ± SD (mean anti-E I titer) . The anti- E 1 titer could be deduced from the signal to noise ratio as show in Figures 5, 6, 7, and 8. Already at the end of treatment, marked differences could be observed between the 2 groups. Anti-E 1 antibody titers had decreased 6.9 times in LTR but only 1 .5 times in NR. At the end of follow up, the antι-E 1 titers had declined by a factor of 22.5 in the patients with sustained response and even slightly increased in N R. Therefore, based on these data, decrease of anti-E 1 antibody levels during monitoring of IFN-σ therapy correlates with long-term, sustained response to treatment. The antι-E 1 assay may be very useful for prognosis of long-term response to IFN treatment, or to treatment of the hepatitis C disease in general. This finding was not expected. On the contrary, the inventors had expected the anti-E 1 antibody levels to increase during the course of IFN treatment in patients with long term response. As is the case for hepatitis B, the virus is cleared as a consequence of the seroconversion for anti-HBsAg antibodies. Also in many other virus infections, the virus is eliminated when anti-envelope antibodies are raised. However, in the experiments of the present invention, anti-E 1 antibodies clearly decreased in patients with a long-term response to treatment, while the antibody-level remained approximately at the same level in non-responding patients. Although the outcome of these experiments was not expected, this non-obvious finding may be very important and useful for clinical diagnosis of HCV infections. As shown in Figures 9, 1 0, 1 1 , and 1 2, anti-E2 levels behaved very differently in the same patients studied and no obvious decline in titers was observed as for anti-E 1 antibodies. Figure 35 gives a complete overview of the pilot study. As can be deduced from Table 2, the anti-E 1 titers were on average at least 2 times higher at the start of treatment in long term responders compared with incomplete responders to treatment. Therefore, measuring the titer of anti-E1 antibodies at the start of treatment, or monitoring the patient during the course of infection and measuring the anti-E 1 titer, may become a useful marker for clinical diagnosis of hepatitis C. Furthermore, the use of more defined regions of the E 1 or E2 proteins may become desirable, as shown in example 7.3. 7 2 Analysis of E 1 and E2 antibodies in a larger patient cohort The pilot study lead the inventors to conclude that, in case infection was completely cleared, antibodies to the HCV envelope proteins changed more rapidly than antibodies to the more conventionally studied HCV antigens, with E 1 antibodies changing most vigorously We therefore included more type 1 b and 3a-ιnfected LTR and further supplemented the cohort with a matched series of NR, such that both groups included 14 patients each. Some partial responders (PR) and responders with relapse (RR) were also analyzed. Figure 36 depicts average E 1 antibody (E 1 Ab) and E2 antibody (E2Ab) levels in the LTR and NR groups and Tables 4 and 5 show the statistical analyses In this larger cohort, higher E 1 antibody levels before IFN-σ therapy were associated with LTR (P < 0.03). Since much higher E1 antibody levels were observed in type 3a-ιnfected patients compared with type 1 b-mfected patients (Figure 37), the genotype was taken into account (Table 4). Within the type 1 b-mfected group, LTR also had higher E 1 antibody levels than NR at the initiation of treatment [P < 0 05]; the limited number of type 3a- infected NR did not allow statistical analysis. Of antibody levels monitored in LTR during the 1 .5-year follow up period, only E 1 antibodies cleared rapidly compared with levels measured at initiation of treatment [P = 0.0058, end of therapy; P = 0.0047 and P = 0.0051 at 6 and 1 2 months after therapy, respectively]. This clearance remained significant within type 1 - or type 3- mfected LTR (average P values < 0.05). These data confirmed the initial finding that E1 Ab levels decrease rapidly in the early phase of resolvement This feature seems to be independent of viral genotype. In NR, PR, or RR, no changes in any of the antibodies measured were observed throughout the follow up period. In patients who responded favourably to treatment with normalization of ALT levels and HCV-RNA negative during treatment, there was a marked difference between sustained responders (LTR) and responders with a relapse (RR). In contrast to LTR, RR did not show any decreasing E 1 antibody levels, indicating the presence of occult HCV infection that could neither be demonstrated by PCR or other classical techniques for detection of HCV-RNA, nor by raised ALT levels. The minute quantities of viral RNA, still present in the RR group during treatment, seemed to be capable of antι-E1 B cell stimulation Antι-E 1 monitoring may therefore not only be able to discriminate LTR from NR, but also from RR. 7 3 Monitoring of antibodies of defined regions of the E 1 protein Although the molecular biological approach of identifying HCV antigens resulted in unprecedented breakthrough in the development of viral diagnostics, the method of immune screening of Λgt1 1 libraries predominantly yielded linear epitopes dispersed throughout the core and non-structural regions, and analysis of the envelope regions had to await cloning and expression of the E 1 /E2 region in mammalian cells This approach sharply contrasts with many other viral infections of which epitopes to the envelope regions had already been mapped long before the deciphering of the genomic structure. Such epitopes and corresponding antibodies often had neutralizing activity useful for vaccine development and/or allowed the development of diagnostic assays with clinical or prognostic significance (e.g antibodies to hepatitis B surface antigen) As no HCV vaccines or tests allowing clinical diagnosis and prognosis of hepatitis C disease are available today, the characterization of viral envelope regions exposed to immune surveillance may significantly contribute to new directions in HCV diagnosis and prophylaxis. Several 20-mer peptides (Table 3) that overlapped each other by 8 ammo acids, were synthesized according to a previously described method (EP-A-0 489 968) based on the HC-J 1 sequence (Okamoto et al., 1 990). None of these, except peptide env35 (also referred to as E 1 -35), was able to detect antibodies in sera of approximately 200 HCV cases. Only 2 sera reacted slightly with the env35 peptide However, by means of the antι-E 1 ELISA as described in example 6, it was possible to discover additional epitopes as follows- The antι-E1 ELISA as described in example 6 was modified by mixing 50 /yg/ml of E 1 peptide with the 1 /20 diluted human serum in sample diluent Figure 1 3 shows the results of reactivity of human sera to the recombinant E1 (expressed from vvHCV-40) protein, in the presence of single or of a mixture of E 1 peptides. While only 2% of the sera could be detected by means of E1 peptides coated on strips in a Line Immunoassay format, over half of the sera contained antι-E 1 antibodies which could be competed by means of the same peptides, when tested on the recombinant E 1 protein. Some of the muπne monoclonal antibodies obtained from Balb/C mice after injection with purified E 1 protein were subsequently competed for reactivity to E 1 with the single peptides (Figure 14) Clearly, the region of env53 contained the predominant epitope, as the addition of env53 could substantially compete reactivity of several sera with E1 , and antibodies to the env31 region were also detected. This finding was surprising, since the eπv53 and env31 peptides had not sho wn any reactivity when coated directly to the solid phase Therefore peptides were synthesized using technology described by applicant previously (in WO 93/1 8054). The following peptides were synthesized peptide env35A-bιotιn NH 2 -SNSSEAADMIMHTPGCV-GKbιotιn (SEQ ID NO 51 ) spanning ammo acids 208 to 227 of the HCV polyprotein in the E 1 region peptide bιotιn-env53 ('epitope A') biotm-GG-ITGHRMAWDMMMNWSPTTAL-COOH (SEQ ID NO 52) spanning ammo acids to 31 3 of 332 of the HCV polyprotein in the E 1 region peptide 1 bE 1 ('epitope B') H 2 N-YEVRNVSGIYHVTNDCSNSSIVYEAADMIMHTPGCGK -bιotιn(SEQID NO 53) spanning ammo acids 1 92 to 228 of the HCV polyprotein in the E1 region and compared with the reactivities of peptides E l a-BB (biotin-GG- TPTVATRDGKLPATQLRRHIDLL, SEQ ID NO 54) and E 1 b-BB (biotm-GG- TPTLAARDASVPTTTIRRHVDLL, SEQ ID NO 55) which are derived from the same region of sequences of genotype 1 a and 1 b respectively and which have been described at the IXth international virology meeting in Glasgow, 1 993 ('epitope C). Reactivity of a panel of HCV sera was tested on epitopes A, B and C and epitope B was also compared with env35A (of 47 HCV-positive sera, 8 were positive on epitope B and none reacted with env35 A). Reactivity towards epitopes A, B, and C was tested directly to the biotmylated peptides (50 /yg/ml) bound to streptavidin-coated plates as described in example 6. Clearly, epitopes A and B were most reactive while epitopes C and env35A-bιotιn were much less reactive. The same series of patients that had been monitored for their reactivity towards the complete E1 protein (example 7.1 .) was tested for reactivity towards epitopes A, B, and C. Little reactivity was seen to epitope C, while as shown in Figures 1 5, 1 6, 1 7, and 1 8, epitopes A and B reacted with the majority of sera. However, antibodies to the most reactive epitope (epitope A) did not seem to predict remission of disease, while the antι-1 bE 1 antibodies (epitope B) were present almost exclusively in long term responders at the start of IFN treatment. Therefore, antι- 1 bE 1 (epitope B) antibodies and antι-env53 (epitope A) antibodies could be shown to be useful markers for prognosis of hepatitis C disease. The env53 epitope may be advantageously used for the detection of cross-reactive antibodies (antibodies that cross-react between major genotypes) and antibodies to the env53 region may be very useful for universal E1 antigen detection in serum or liver tissue Monoclonal antibodies that recognized the env53 region were reacted with a random epitope library. In 4 clones that reacted upon immunoscreenmg with the monoclonal antibody 5E 1 A 1 0, the sequence -GWD- was present. Because of its analogy with the universal HCV sequence present in all HCV variants in the env53 region, the sequence AWD is thought to contain the essential sequence of the env53 cross-reactive muπne epitope The env31 clearly also contains a variable region which may contain an epitope in the ammo terminal sequence -YQVRNSTGL- (SEQ ID NO 93) and may be useful for diagnosis Env 31 or E 1 -31 as shown in Table 3, is a part of the peptide 1 bE 1 Peptides E 1 -33 and E 1 -51 also reacted to some extent with the muπne antibodies, and peptide E 1 -55 (containing the variable region 6 (V6); spanning ammo acid positions 329-336) also reacted with some of the patient sera Antι-E2 antibodies clearly folio wed a different pattern than the antι-E 1 antibodies, especially in patients with a long-term response to treatment Therefore, it is clear that the decrease in anti-envelope antibodies could not be measured as efficiently with an assay employing a recombinant E1 /E2 protein as with a single antι-E1 or antι-E2 protein. The antι-E2 response would clearly blur the antι-E 1 response in an assay measuring both kinds of antibodies at the same time. Therefore, the ability to test anti-envelope antibodies to the single E 1 and E2 proteins, was shown to be useful. 7 4 Mapping of antι-E2 antibodies Of the 24 antι-E2 Mabs only three could be competed for reactivity to recombinant E2 by peptides, two of which reacted with the HVRI region (peptides E2- 67 and E2-69, designated as epitope A) and one which recognized an epitope competed by peptide E2-1 3B (epitope C). The majority of muπne antibodies recognized conformational antι-E2 epitopes (Figure 1 9). A human response to HVRI (epitope A), and to a lesser extent HVRII (epitope B) and a third linear epitope region (competed by peptides E2-23, E2-25 or E2-27, designated epitope E) and a fourth linear epitope region (competed by peptide E2-1 7B, epitope D) could also frequently be observed, but the majority of sera reacted with conformational epitopes (Figure 20). These conformational epitopes could be grouped according to their relative positions as follows: the IgG antibodies in the supernatant of hybπdomas 1 5C8C 1 1 2D 1 1 F 1 9G3E6, 8G 1 0D 1 H 9 1 0D 3C4, 4H6B2, 1 7F2C2, 5H6A7, 1 5B7A2 recognizing conformational epitopes were purified by means of protein A affinity chromatography and 1 mg/ml of the resulting IgG's were biotmylated in borate buffer in the presence of biotin Biotinylated antibodies were separated from free biotin by means of gelfiltration chromatography Pooled biotmylated antibody fractions were diluted 1 00 to 1 0,000 times E2 protein bound to the solid phase was detected by the biotmylated IgG in the presence of 1 00 times the amount of non-biotinylated competing antibody and subsequently detected by alkaline phosphatase labeled streptavidm. Percentages of competition are given in Table 6 Based on these results, 4 conformational antι-E2 epitope regions (epitopes F, G, H and I) could be delineated (Figure 38). Alternatively, these Mabs may recognize mutant linear epitopes not represented by the peptides used in this study. Mabs 4H6B2 and 1 0D3C4 competed reactivity of 1 6A6E7, but unlike 1 6A6E7, they did not recognize peptide E2- 1 3B These Mabs may recognize variants of the same linear epitope (epitope C) or recognize a conformational epitope which is sterically hindered or changes conformation after binding of 1 6A6E7 to the E2-1 3B region (epitope H). Example 8: E1 glycosylation mutants 8.1 . Introduction The E 1 protein encoded by vvHCVI OA, and the E2 protein encoded by vvHCV41 to 44 expressed from mammalian cells contain 6 and 1 1 carbohydrate moieties, respectively. This could be shown by incubating the lysate of vvHCV I OA-mfected or vvHCV44-ιnfected RK 1 3 cells with decreasing concentrations of glycosidases (PNGase F or Endoglycosidase H, (Boehrmger Mannhem Biochemica) according to the manufacturer's instructions), such that the proteins in the lysate (including E l ) are partially deglycosylated (Fig. 39 and 40, respectively). Mutants devoid of some of their glycosylation sites could allow the selection of envelope proteins with improved immunological reactivity For HIV for example, gp 1 20 proteins lacking certain selected sugar-addition motifs, have been found to be particularly useful for diagnostic or vaccine purpose The addition of a new oligosaccharide side chain in the hemagglutmm protein of an escape mutant of the A/Hong Kong/3/68 (H3N2) influenza virus prevents reactivity with a neutralizing monoclonal antibody (Skehel et al, 1 984) When novel glycosylation sites were introduced into the influenza hemaglutinm protein by site-specific mutagenesis, dramatic antigenic changes were observed, suggesting that the carbohydrates serve as a modulator of antigenicity (Gallagher et al., 1 988). In another analysis, the 8 carbohydrate-addition motifs of the surface protein gp70 of the Friend Muπne Leukemia Virus were deleted. Although seven of the mutations did not affect virus mfectivity, mutation of the fourth glycosylation signal with respect to the ammo terminus resulted in a non-infectious phenotype (Kayman et al., 1 991 ) Furthermore, it is known in the art that addition of N-lmked carbohydrate chains is important for stabilization of folding intermediates and thus for efficient folding, prevention of malfoldmg and degradation in the endoplasmic reticulum, oligomeπzation, biological activity, and transport of glycoprotems (see reviews by Rose et al., 1 988; Doms et al., 1 993; Helenius, 1 994). After alignment of the different envelope protein sequences of HCV genotypes, it may be inferred that not all 6 glycosylation sites on the HCV subtype 1 b E 1 protein are required for proper folding and reactivity, since some are absent in certain (sub)types The fourth carbohydrate motif (on Asn251 ), present in types 1 b, 6a, 7, 8, and 9, is absent in all other types know today. This sugar-addition motif may be mutated to yield a type 1 b E 1 protein with improved reactivity. Also the type 2b sequences show an extra glycosylation site in the V5 region (on Asn299). The isolate S83, belonging to genotype 2c, even lacks the first carbohydrate motif in the V 1 region (on Asn), while it is present on all other isolates (Stuyver et al., 1 994) However, even among the completely conserved sugar-addition motifs, the presence of the carbohydrate may not be required for folding, but may have a role in evasion of immune surveillance. Therefore, identification of the carbohydrate addition motifs which are not required for proper folding (and reactivity) is not obvious, and each mutant has to be analyzed and tested for reactivity. Mutagenesis of a glycosylation motif (NXS or NXT sequences) can be achieved by either mutating the codons for N, S, or T, in such a way that these codons encode ammo acids different from N in the case of N, and/or ammo acids different from S or T in the case of S and in the case of T. Alternatively, the X position may be mutated into P, since it is known that NPS or NPT are not frequently modified with carbohydrates. After establishing which carbohydrate-addition motifs are required for folding and/or reactivity and which are not, combinations of such mutations may be made. 8.2. Mutagenesis of the E 1 protein All mutations were performed on the E 1 sequence of clone HCCI 1 0A (SEQ ID NO. 5). The first round of PCR was performed using sense primer 'GPT' (see Table 7) targettmg the GPT sequence located upstream of the vaccinia 1 1 K late promoter, and an antisense primer (designated GLY#, with # representing the number of the glycosylation site, see Fig. 41 ) containing the desired base change to obtain the mutagenesis. The six GLY# primers (each specific for a given glycosylation site) were designed such that: - Modification of the codon encoding for the N-glycosylated Asn (AAC or AAT) to a Gin codon (CAA or CAG). Glutamine was chosen because it is very similar to asparagine (both ammo acids are neutral and contain non-polar residues, glutamine has a longer side chain (one more -CH 2 - group). - The introduction of silent mutations in one or several of the codons downstream of the glycosylation site, in order to create a new unique or rare (e.g. a second Smal site for E 1 Gly5) restriction enzyme site. Without modifying the amino acid sequence, this mutation will provide a way to distinguish the mutated sequences from the original E 1 sequence (pvHCV-1 0A) or from each other (Figure 41 ) . This additional restriction site may also be useful for the construction of new hybrid (double, triple, etc.) glycosylation mutants. - 1 8 nucleotides extend 5' of the first mismatched nucleotide and 1 2 to 1 6 nucleotides extend to the 3' end. Table 7 depicts the sequences of the six GLY# primers overlapping the sequence of N-linked glycosylation sites. For site-directed mutagenesis, the 'mispπming' or 'overlap extension' (Horton, 1 993) was used. The concept is illustrated in Figures 42 and 43. First, two separate fragments were amplified from the target gene for each mutated site. The PCR product obtained from the 5' end (product GLY#) was amplified with the 5' sense GPT primer (see Table 7) and with the respective 3' antisense GLY# primers. The second fragment (product 0VR#) was amplified with the 3 antisense TKr, primer and the respective 5 sense primers (0VR# primers, see Table 7 Figure 43) The OVR# primers target part of the GLY# primer sequence Tnerefore, the two groups of PCR products share an overlap region of identical sequence When these intermediate products are mixed (GLY- 1 with OVR- 1 , GLY-2 with OVR-2, etc ), melted at high temperature, and reannealed, the top sense strand of product GLY# can anneal to the antisense strand of product OVR# (and vice versa) in such a way that the two strands act as primers for one another (see Fig 42 B ) Extension of the annealed overlap by Taq polymerase during two PCR cycles created the full-length mutant molecule E1 Gly#, which carries the mutation destroying the glycosylation site number # Sufficient quantities of the E 1 GLY# products for cloning were generated in a third PCR by means of a common set of two internal nested primers These two new primers are respectively overlapping the 3' end of the vaccinia 1 1 K promoter (sense GPT-2 primer) and the 5' end of the vaccinia thymidme kmase locus (antisense TK R -2 primer, see Table 7) All PCR conditions were performed as described in Stuyver et al ( 1 993) Each of these PCR products was cloned by EcoRI/BamHI cleavage into the EcoRI/BamHI-cut vaccinia vector containing the original E 1 sequence (pvHCV- 1 0A) The selected clones were analyzed for length of insert by EcoRI/BamH I cleavage and for the presence of each new restriction site. The sequences overlapping the mutated sites were confirmed by double-stranded sequencing 8 3 Analysis of E 1 glycosylation mutants Starting from the 6 plasmids containing the mutant E 1 sequences as described in example 8.2, recombinant vaccinia viruses were generated by recombination with wt vaccinia virus as described in example 2.5 Briefly, 1 75 cnXflasks of subconfluent RK 1 3 cells were infected with the 6 recombinant vaccinia viruses carrying the mutant E 1 sequences, as well as with the vvHCV-1 0A (carrying the non-mutated E 1 sequence) and wt vaccinia viruses. Cells were lysed after 24 hours of infection and analyzed on western blot as described in example 4 (see Figure 44A) All mutants showed a faster mobility (corresponding to a smaller molecular weight of approximately 2 to 3 kDa) on SDS-PAGE than the original E 1 protein; confirming that one carbohydrate moiety was not added. Recombinant viruses were also analyzed by PCR and restriction enzyme analysis to confirm the identity of the different mutants Figure 44B shows that all mutants (as shown in Figure 41 ) contained the expected additional restriction sites Another part of the cell lysate was used to test the reactivity of the different mutant by ELISA The lysates were diluted 20 times and added to microwell plates coated with the lectm GNA as described in example 6 Captured (mutant) E 1 glycoprotems were left to react with 20-tιmes diluted sera of 24 HCV-infected patients as described in example 6 Signal to noise (S/N) values (OD of GLY#/OD of wt) for the six mutants and E 1 are shown in Table 8 The table also shows the ratios between S/N values of GLY# and E 1 proteins It should be understood that the approach to use cell lysates of the different mutants for comparison of reactivity with patient sera may result in observations that are the consequence of different expression levels rather then reactivity levels Such difficulties can be overcome by purification of the different mutants as described in example 5, and by testing identical quantities of all the different E 1 proteins However, the results shown in table 5 already indicate that removal of the 1 st (GLY 1 ), 3rd (GLY3), and 6th (GLY6) glycosylation motifs reduces reactivity of some sera while removal of the 2nd and 5th site does not Removal of GLY4 seems to improve the reactivity of certain sera These data indicate that different patients react differently to the glycosylation mutants of the present invention Thus, such mutant E1 proteins may be useful for the diagnosis (screening, confirmation, prognosis etc ) and prevention of HCV disease Example 9: Expression of HCV E2 protein in glvcosylation-deficient yeasts The E2 sequence corresponding to clone HCCL41 was provided with the σ- mating factor pre/pro signal sequence, inserted in a yeast expression vector and S_ cerevisiae cells transformed with this construct secreted E2 protein into the growth medium. It was observed that most glycosylation sites were modified with high- mannose type glycosylations upon expression of such a construct in S cerevisiae strains (Figure 45) This resulted in a too high level of heterogeneity and in shielding of reactivity, which is not desirable for either vaccine or diagnostic purposes To overcome this problem, S. cerevisiae mutants with modified glycosylation pathways were generated by means of selection of vanadate-resistant clones Such clones were analyzed for modified glycosylation pathways by analysis of the molecular weight and heterogeneity of the glycoprotein mvertase This allowed us to identify different glycosylation deficient S cerevisiae mutants The E2 protein was subsequently expressed in some of the selected mutants and left to react with a monoclonal antibody as described in example 7, on western blot as described in example 4 (Figure 46) Example 10. General utility The present results show that not only a good expression system but also a good purification protocol are required to reach a high reactivity of the HCV envelope proteins with human patient sera. This can be obtained using the proper HCV envelope protein expression system and/or purification protocols of the present invention which guarantee the conservation of the natural folding of the protein and the purification protocols of the present invention which guarantee the elimination of contaminating proteins and which preserve the conformation, and thus the reactivity of the HCV envelope proteins. The amounts of purified HCV envelope protein needed for diagnostic screening assays are in the range of grams per year. For vaccine purposes, even higher amounts of envelope protein would be needed. Therefore, the vaccinia virus system may be used for selecting the best expression constructs and for limited upscalmg, and large-scale expression and purification of single or specific oligomeric envelope proteins containing high-mannose carbohydrates may be achieved when expressed from several yeast strains. In the case of hepatitis B for example, manufacturing of HBsAg from mammalian cells was much more costly compared with yeast-derived hepatitis B vaccines. The purification method dislcosed in the present invention may also be used for 'viral envelope proteins' in general. Examples are those derived from Flaviviruses, the newly discovered GB-A, GB-B and GB-C Hepatitis viruses, Pestiviruses (such as Bovine viral Diarrhoea Virus (BVDV), Hog Cholera Virus (HCV), Border Disease Virus (BDV)), but also less related virusses such as Hepatitis B Virus (mainly for the purification of HBsAg). The envelope protein purification method of the present invention may be used for intra- as well as extracellularly expressed proteins in lower or higher eukaryotic cells or in prokaryotes as set out in the detailed description section. Table 1: Recombinant vaccinia plasmids and viruses nt: nucleotide aa: aminoacid Kl: Klenow DNA Pol filling T4: T4 DNA Pol filling Position: aminoacid position in the HCV polyprotein sequence SUBSTITUTE SHET (RULE 26) 54 Table 1 - continued: Recombinant vaccinia plasmids and viruses nt: nucleotide aa: aminoacid Kl: Klenow DNA Pol filling T4. T4 DNA Pol filling Position: aminoacid position in the HCV polyprotein sequence SUBSTITUTE SHET (RULE 26) Table 2 : Summary of anti-E 1 tests S/N + SD (mean anti-E1 titer) LTR : Long-term, sustained response for more than 1 year NR : No response, response with relapse, or partial response Table 3 Synthetic peptides for competition studies PROTEIN PEPTIDE AMINO ACID SEQUENCE E1 E1-31 LLSCLTVPASAYQVRNSTGL E1-33 QVRNSTGLYHVTNDCPNSSI E1-35 NDCPNSSIVYEAHDAILHTP E1-35A SNSSIVYEAADMIMHTPGCV E1-37 HDAILHTPGCVPCVREGNVS E1-39 CVREGNVSRCWVAMTPTVAT E1-41 AMTPTVATRDGKLPATQLRR E1-43 LPATQLRRHIDLLVGSATLC E1-45 LVGSATLCSALYVGDLCGSV E1-49 QLFTFSPRRHWTTQGCNCSI E1-51 TQGCNCSIYPGHITGHRMAW E1-53 ITGHRMAWDMMMNWSPTAAL E1-55 NWSPTAALVMAQLLRIPQAI E1-57 LLRIPQAILDMIAGAHWGVL E1-59 AGAHWGVLAGIAYFSMVGNM E1-63 VVLLLFAGVDAETIVSGGQA E2-67 SGLVSLFTPGAKQNIQLINT E2-69 QNIQLINTNGSWHINSTALN E2-$3B LNCNESLNTGWWLAGLIYQHK E2-$ 1 B AGLIYQHKFNSSGCPERLAS E2-1 B GCPERLASCRPLTDFDQGWG E2-3B TDFDQGWGPISYANGSGPDQ E2-5B ANGSGPDQRPYCWHYPPKPC E2-7B WHYPPKPCGIVPAKSVCGPV E2-9B AKSVCGPVYCFTPSPVVVGT E2- 1 1 B PSPVVVGTTDRSGAPTYSWG E2- 1 3B GAPTYSWGENDTDVFVLNNT E2- 1 7B GNWFGCTWMNSTGFTKVCGA E2- 1 9B GFTKVCGAPPVCIGGAGNNT E2-21 IGGAGNNTLHCPTDCFRKHP E2-23 TDCFRKHPDATYSRCGSGPW E2-25 SRCGSGPWITPRCLVDYPYR E2-27 CLVDYPYRLWHYPCTINYTI E2-29 PCTINYTIFKIRMYVGGVEH E2-31 MYVGGVEHRLEAACNWTPGE E2-33 ACNWTPGERCDLEDRDRSEL E2-35 EDRDRSELSPLLLTTTQWQV Table 4. Change of Envelope Antibody levels over time (complete study, 28 patients) Wilcoxon Signed ElAb NR ElAb NR E1Ab NR E1Ab LTR E1Ab LTR E1Ab LTR E2Ab NR E1Ab LTR Rank test (P values) All type 1b type 3a All type 1b type 3a All All End of therapy* 0.1167 6 months follow up * 0.86 12 months follow up* 0.7989 Data were compared with values obtained at initiation of therapy ' P values < 0.05 en CO ~Z m o z ro <zn Table 5. Difference between LTR and NR (complete study) Mann-Withney E1Ab S/N E1Ab titers E1Ab S/N E1Ab S/N E2Ab S/N U test (P values) All All type 1b type 3a All Initiation of therapy 0.0257 End of therapy 0.1 42 6 months follow up 1 12 months follow up 0.67 P values < 0.05 £ CTϊ za m ro Table 6. Competition experiments between murine E2 monoclonal antibodies Decrease (%) of aπti E2 reactivity of biotinylated anti E2 mabs competitor 17H10F4D10 2F10H10 16A6E7 10D3C4 4H6B2 17C2F2 9G3E6 12D11F1 15C8C1 8G10D1H9 o competitor controls Table 7. Primers 5'-GTTTAACCACTGCATGATG-3' 5'-GTCCCATCGAGTGCGGCTAC-3' 5'-CGTGACATGGTACATTCCGGACACTTGGCGCACTTCATAAGCGGA-3' 5'-TGCCTCATACACAATGGAGCTCTGGGACGAGTCGTTCGTGAC-3' 5'-TACCCAGCAGCGGGAGCTCTGTTGCTCCCGAACGCAGGGCAC-3' 5'-TGTCGTGGTGGGGACGGAGGCCTGCCTAGCTGCGAGCGTGGG-3' 5'-CGTTATGTGGCCCGGGTAGATTGAGCACTGGCAGTCCTGCACCGTCTC-3' 5'-CAGGGCCGTTGTAGGCCTCCACTGCATCATCATATCCCAAGC-3' 10 5'-CCGGAATGTACCATGTCACGAACGAC-3' 5'-GCTCCATTGTGTATGAGGCAGCGG-3' 5'-GAGCTCCCGCTGCTGGGTAGCGC-3' 5'-CCTCCGTCCCCACCACGACAATACG 3' 5'-CTACCCGGGCCACATAACGGGTCACCG 3' 15 5'-GGAGGCCTACAACGGCCCTGGTGG-3' 5'-TTCTATCGATTAAATAGAATTC -3' 5'-GCCATACGCTCACAGCCGATCCC-3' itional restriction site ations with respect to the original HCCI 1 0A sequence REFERENCES Bailey, J. and Cole, R. (1959) J. Biol. Chem.234, 1733-1739. Ballou, L., Hitzeman, R., Lewis, M. & Ballou, C. (1991) PNAS 88, 3209-3212. Benesch, R., Benesch, R.E., Gutcho, M. & Lanfer, L. (1956) Science 123, 981. Cavins, J. & Friedman. (1970) Anal. Biochem. 35, 489. Cleland, W. 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Claims: CLAIMS 1 Method for purifying recombinant HCV single or specific oligomeric envelope proteins selected from the group consisting of E 1 and/or E2 and/or E 1 /E2, characterized in that upon lysing the transformed host cells to isolate the recombinantly expressed protein a disulphide bond cleavage or reduction step is carried out with a disulphide bond cleavage agent. 2. Method acco ling to claim 1 , wherein said disulphide cleavage or reduction step is carried out under partial cleavage or reducing conditions 3. Method according to claim 1 or 2, wherein said disulphide bond cleavage agent is dithiothreitol (DTT), preferably in a concentration range of 0 1 to 50 mM, preferably 0 1 to 20 mM, more preferably 0.5 to 1 0 mM . 4. Method according to claim 1 , wherein said disulphide bond cleavage agent is a detergent. 5 Method according to claim 4, wherein said detergent is Empigen-BB, preferably at a concentration of 1 to 1 0%, more preferably at a concentration of 3.5 % 6. Method according to claim 1 or 2, wherein said disulphide bond cleaving agent comprises a combination of a classical disulphide bond cleavage agent, such as DTT, and a detergent, such as Empigen-BB. 7. Method according to any of claims 1 to 6, further comprising the step of blocking disulphide bond reformation with an SH group blocking agent 8 Method according to claim 7, wherein said SH group blocking agent is N- ethylmaleimide (NEM) or a derivative thereof. 9. Method according to claim 7, wherein said step of blocking the disulphide bond reformation is brought about by low pH conditions. 1 0 Method according to any of claims 1 to 9 further cnaracteπzed by at least the following steps lysing recombinant E 1 and or E2 and or E 1 E2 expressing host cells, possibly in the presence of an SH blocking agent such as N- ethylmaleimide (NEM), recovering said HCV envelope proteins by affinity purification such as by means of lectm-chromatography, such as lentil-lectin chromatography, or by means of immunoaffinity using antι-E 1 and/or antι-E2 specific monoclonal antibodies, - reduction or cleavage of the disulfide bonds with a disulphide bond cleaving agent, such as DTT, preferably also in the presence of an SH blocking agent, such as NEM or Biotin-NEM, and, recovering the reduced E 1 and/or E2 and or E 1 E2 envelope proteins by gelfiltration and possibly also by a subsequent Ni-IMAC chromatography and desalting step. 1 1 Composition comprising essentially purified recombinant HCV single or specific oligomeric recombinant envelope proteins selected from the group consisting of E 1 and/or E2 and/or E 1 /E2, characterized as being isolated by a method according to any of claims 1 to 1 0. 1 2 Composition according to claim 1 1 , further characterized in that said recombinant HCV envelope proteins are expressed from recombinant mammalian cells such as vaccinia. 1 3 Composition according to claim 1 1 , further characterized in that said recombinant HCV envelope proteins are expressed from recombinant yeast cells. 14. Composition according to claim 1 1 , further characterized in that said recombinant HCV envelope proteins are the expression product of at least one of the recombinant vectors according to any of claims 1 5 to 24 1 5. Recombinant vector comprising a vector sequence, an appropriate prokaryotic, eukaryotic or viral promoter sequence followed by a nucleotide sequence allowing the expression of a single or specific oligomeric E 1 and/or E2 and/or E 1 /E2 protein. 1 6 Recombinant vector according to claim 1 5 with said nucleotide sequence being characterized further in that it encodes a single HCV E 1 protein starting in the region between ammo acid positions 1 and 1 92 and ending in the region between ammo acid positions 250 and 400, more particularly ending in the region between positions 250 and 341 , even more preferably ending in the region between position 290 and 341 1 7 Recombinant vector according to claim 1 6, with said nucleotide sequence being characterized further in that it encodes a single HCV E 1 protein starting in the region between ammo acid positions 1 1 7 and 1 92 and ending in the region between ammo acid positions 263 and 400, more particularly ending in the region between positions 250 and 326. 1 8 Recombinant vector according to any of claims 1 6 or 1 7, with said nucleotide sequence being characterized further in that it encodes a single HCV E 1 protein bearing a deletion of the first hydrophobic domain between positions 264 to 293, plus or minus 8 ammo acids. 1 9. Recombinant vector according to claim 1 5, with said nucleotide sequence being characterized further in that it encodes a single HCV E2 protein starting in the region between am o acid positions 290 and 406 and ending in the region between am o acid positions 600 and 820, more particularly starting in the region between positions 322 and 406, even more preferably starting in the region between position 347 and 406 and most preferably starting in the region between positions 364 and 406. 20. Recombinant vector according to claim 1 9, with said nucleotide sequence being characterized further in that it ends at any of am o acid positions 623, 650, 661 , 673, 71 0, 71 5, 720, 746 or 809. 21 . Recombinant vector according to any of claims 1 6 to 20, with said nucleotide sequence being characterized further in that a 5'-termιnal ATG codon and a 3'- termmal stop codon have been added to it. 22. Recombinant vector according to any of claims 1 6 to 21 , with said nucleotide sequence being characterized further in that a factor Xa cleavage site and or 3 to 1 0 preferably 6, histidine codons have been added 3'-termιnally to the coding region 23 Nucleic acid comprising any of the sequences as represented in SEQ ID NO 3, 5 , 7, 9, 1 1 , 1 3, 21 , 23, 25, 27, 29, 31 , 35, 37, 39, 41 , 43, 45, 47 and 49, or parts thereof . 24 Recombinant vector carrying a recombinant nucleic acid according to claim 23 25 Recombinant vector according to any of claims 1 5 to 24, further characterized in that at least one of the glycosylation sites present in said E 1 or E2 protein has been removed at the nucleic acid level 26. A host cell transformed with at least one recombinant vector according to any of claims 1 5 to 26, wherein said vector comprises a nucleotide sequence encoding HCV E 1 and/or E2 and/or E 1 /E2 protein as defined in any of claims 1 5 to 23 in addition to a regulatory sequence operable in said host cell and capable of regulating expression of said HCV E 1 and/or E2 and/or E 1 /E2 protein. 27. A recombinant E 1 and/or E2 and/or E 1 /E2 protein expressed by a host cell according to claim 26. 28. Method according to any of claims 1 to 1 0, further characterized as comprising at least the following steps: growing a host cell as defined in claim 26 transformed with a recombinant vector according to any of claims 1 5 to 25 in a suitable culture medium, causing expression of said vector sequence as defined in any of claims 1 6 to 25 under suitable conditions, and, lysing said transformed host cells, preferably in the presence of an SH group blocking agent, such as N-ethylmaleimide (NEM), - recovering said HCV envelope protein by affinity purification by means of for instance lectm-chromatography or immunoaffinity chromatography using anti- EI and/or antι-E2 specific monoclonal antibodies, with said lectm being preferably lentil-lectin, followed by, incubation of the eluate of the previous step with a disulphide bond cleavage agent, such as DTT, preferably also in the presence of an SH group blocking agent, such as NEM or Biotin-NEM, and, isolating the HCV single or specific oligomeric E1 and or E2 and or E1 E2 proteins by means of gelfiltration and possibly also by means of an additional NX-IMAC chromatography and desalting step. 29. A composition comprising at least one of the following E1 and/or E2 peptides E1-31 (SEQ ID NO 56) spanning ammo acids 181 to 200 of the Core'EI V1 region, E1-33 (SEQ ID NO 57) spanning ammo acids 193 to 212 of the E1 region, E1-35 (SEQ ID NO 58) spanning am o acids 205 to 224 of the E1 V2 region (epitope B), E1-35A (SEQ ID NO 59) spanning ammo acids 208 to 227 of the E1 V2 region (epitope B), 1bE1 (SEQ ID NO 53) spanning am o acids 192 to 228 of E1 regions (V1, C1, and V2 regions (containing epitope B), E1-51 (SEQ ID NO 66) spanning ammo acids 301 to 320 of the E1 region, E1-53 (SEQ ID NO 67) spanning ammo acids 313 to 332 of the E1 C4 region (epitope A), E1-55 (SEQ ID NO 68) spanning am o acids 325 to 344 of the E1 region. Env 67 or E2-67 (SEQ ID NO 72) spanning ammo acid positions 397 to 416 of the E2 region (epitope A), Env 69 or E2-69 (SEQ ID NO 73) spanning ammo acid positions 409 to 428 of the E2 region (epitope A), Env 23 or E2-23 (SEQ ID NO 86) spanning positions 583 to 602 of the E2 region (epitope E), Env 25 or E2-25 (SEQ ID NO 87) spanning positions 595 to 614 of the E2 region (epitope E), Env 27 or E2-27 (SEQ ID NO 88) spanning positions 607 to 626 of the E2 region (epitope E), Env 17B or E2-17B (SEQ ID NO 83) spanning positions 547 to 566 of the E2 region (epitope D), Env 13B or E2-13B (SEQ ID NO 82) spanning positions 523 to 542 of the E2 region (epitope C). 30 A composition comprising at least one of the following E2 conformational epitopes. epitope F recognized by monoclonal antibodies 1 5C8C 1 1 2D 1 1 F 1 and 8G 1 0D 1 H9, epitope G recognized by monoclonal antibody 9G 3E6, epitope H (or C) recognized by monoclonal antibodies 1 0D3C4 and 4H6B2, epitope I recognized by monoclonal antibody 1 7F2C2 31 An E 1 and/or E2 specific monoclonal antibody raised upon immunization with a composition according to any of claims 1 1 to 1 4 or 29 to 30 32. An E 1 and/or E2 specific monoclonal antibody according to claim 31 for use as a medicament, more particularly for incorporation into an immunoassay kit for detecting the presence of HCV E 1 or E2 antigen, for prognosis/monitoring of disease or for HCV therapy. 33. Use of an E 1 and/or E2 specific monoclonal antibody according to claim 31 for the preparation of an immunoassay kit for detecting HCV E 1 or E2 antigens, for the preparation of a kit for prognosing/monitormg of HCV disease or for the preparation of a HCV medicament. 34. Method for in vitro diagnosis of HCV antigen present in a biological sample, comprising at least the following steps: (ι) contacting said biological sample with an E 1 and/or E2 specific monoclonal antibody according to claim 31 , preferably in an immobilized form under appropriate conditions which allow the formation of an immune complex, (ιι) removing unbound components, (in) incubating the immune complexes formed with heterologous antibodies, with said heterologous antibodies being conjugated to a detectable label under appropriate conditions, (iv) detecting the presence of said immune complexes visually or mechanically. 35 Kit for determining the presence of HCV antigens present in a biological sample comprising at least one E 1 and/or E2 specific monoclonal antibody according to claim 31 , preferably in an immobilized form on a solid substrate, - a buffer or components necessary for producing the buffer enabling binding reaction between these antibdodies and the HCV antigens present in said biological sample, a means for detecting the immune complexes formed in the preceding binding reaction 36 A composition according to any of claims 1 1 to 1 4 or 29 to 30 for use as a medicament. 37 A composition according to any of claims 1 1 to 1 4 or 29 to 30 for use as a vaccine for immunizing a mammal, preferably humans, against HCV, comprising administrating an effective amount of said composition possibly accompanied by pharmaceutically acceptable adjuvants, to produce an immune response. 38 Use of a composition according to any of claims 1 1 to 1 4 or 29 to 30, for the preparation of a vaccine for immunizing a mammal, preferably humans, against HCV, comprising administrating an effective amount of said composition possibly accompanied by pharmaceutically acceptable adjuvants, to produce an immune response. 39. Vaccine composition for immunzing a mammal, preferably humans, against HCV, comprising an effective amount of a composition according to any of claims 1 1 to 14 or 29 to 30 possibly accompanied by pharmaceutically acceptable adjuvants 40. A composition according to any of claims 1 1 to 1 4 or 29 to 30, for in vitro detection of HCV antibodies present in a biological sample. 41 . Use of a composition according to claims 1 1 to 1 4 or 29 to 30, for the preparation of an immunoassay kit for detecting HCV antibodies present in a biological sample. 42 Method for in vitro diagnosis of HCV antibodies present in a biological sample, comprising at least the following steps (ι) contacting said biologica 1 sample with a composition according to any of claims 1 1 to 14 or 29 to 30, preferably in an immobilized form under appropriate conditions which allow the formation of an immune complex, (II ) removing unbound components, (in) incubating the immune complexes formed with heterologous antibodies, with said heterologous antibodies being conjugated to a detectable label under appropriate conditions, (IV ) detecting the presence of said immune complexes visually or mechanically. 43 Kit for determining the presence of HCV antibodies present in a biological sample, comprising: at least one peptide or protein composition according to any of claims 1 1 to 1 4 or 29 to 30, preferably in an immobilized form on a solid substrate, - a buffer or components necessary for producing the buffer enabling binding reaction between these proteins or peptides and the antibodies against HCV present in said biological sample, a means for detecting the immune complexes formed in the preceding binding reaction. 44. Use of composition comprising E 1 proteins according to any of claims 1 1 to 1 4, or parts thereof according to claim 29, more particularly HCV single E 1 proteins or E1 peptides, for in vitro monitoring HCV disease or prognosing the response to treatment, particularly with interferon, of patients suffering from HCV infection comprising: - incubating a biological sample from a patient with HCV infection with an E 1 protein or a suitable part thereof under conditions allowing the formation of an immunological complex, removing unbound components. calculating the antι-E 1 titers present in said sample at the start of and during the course of treatment, monitoring the natural course of HCV disease, or prognosing the response to treatment of said patient on the basis of the amount anti- E1 titers found in said sample at the start of treatment and/or during the course of treatment. 45. Kit for monitoring HCV disease or prognosing the response to treatment, particularly with interferon, of patients suffering from HCV infection comprising: at least one E1 protein or E 1 peptide, more particularly an E 1 protein or E 1 peptide according to any of claims 1 1 to 1 4 or 29, a buffer or components necessary for producing the buffer enabling the binding reaction between these proteins or peptides and the antι-E 1 antibodies present in a biological sample, means for detecting the immune complexes formed in the preceding binding reaction, possibly also an automated scanning and interpretation device for inferring a decrease of antι-E1 titers during the progression of treatment. 46. A serotypmg assay for detecting one or more serological types of HCV present in a biological sample, more particularly for detecting antibodies of the different types of HCV to be detected combined in one assay format, comprising at least the following steps : (i) contacting the biological sample to be analyzed for the presence of HCV antibodies of one or more serological types, with at least one of the E1 and/or E2 and/or E1 /E2 protein compositions according to any of claims 1 1 to 14 or at least one of the E 1 or E2 peptide compositions according to claim 29, preferentially in an immobilized form under appropriate conditions which allow the formation of an immune complex, (ii) removing unbound components, (iii) incubating the immune complexes formed with heterologous antibodies, with said heterologous antibodies being conjugated to a detectable label under appropriate conditions, (iv) detecting the presence of said immune complexes visually or mechanically (e.g by means of densitometry, fluoπmetry, coloπmetry) and inferring the presence of one or more HCV serological types present from the observed binding pattern 47. Kit for serotypmg one or more serological types of HCV present in a biological sample, more particularly for detecting the antibodies to these serological types of HCV comprising. at least one E 1 and/or E2 and/or E 1 /E2 protein acccordmg to any of claims 1 1 to 1 4 or E 1 or E2 peptide according to claim 29, - a buffer or components necessary for producing the buffer enabling the binding reaction between these proteins or peptides and the antι-E 1 antibodies present in a biological sample, means for detecting the immune complexes formed in the preceding binding reaction, - possibly also an automated scanning and interpretation device for detecting the presence of one or more serological types present from the observed binding pattern. 48 A peptide or protein composition according to any of claims 1 1 to 1 4 or 29, for immobilization on a solid substrate and incorporation into a reversed phase hybridization assay, preferably for immobilization as parallel lines onto a solid support such as a membrane strip, for determining the presence or the genotype of HCV according to a method of any of claims 42 or 46.

Inventors: BOSMAN FONS, BUYSE MARIE-ANGE, DE MARTYNOFF GUY, MAERTENS GEERT, BOSMAN, FONS, BUYSE, MARIE-ANGE, DE MARTYNOFF, GUY, MAERTENS, GEERT
Applicants: BOSMAN FONS, BUYSE MARIE ANGE, INNOGENETICS NV, MAERTENS GEERT, MARTYNOFF GUY DE, BOSMAN, FONS, BUYSE, MARIE-ANGE, DE MARTYNOFF, GUY, INNOGENETICS N.V., MAERTENS, GEERT
Application year: 1995
Main classification: C12N15
IPC codes: A61K38, A61K39, A61P1, A61P31, C07K14, C07K16, C12N1, C12N5, C12N15, C12P21, C12Q1, C12R1, G01N33