RECOMBINANT HERPES SIMPLEX gB-gD VACCINE

Abstract: Vaccines and methods for production of vaccines effective against Herpes Simplex Virus (HSV) are provided employing recombinant HSV glycoproteins B and D and immunogenically active fragments thereof.

Description: RECO BINA HERPES SIMPLEX gB-gD VACCINE BACKGROUND OF THE INVENTION Field of the Invention The herpesviruses include the herpes simplex viruses, comprising two closely related variants desig¬ nated types 1 (HSV-1) and 2 (HSV-2). These types cross react strongly but can be distinguished by neutralization titrations. HSV-1 and HSV-2 are responsible for a vari- ety of human diseases, such as skin infections, genital herpes, viral encephalitis and the like. The herpes simplex virus is a double stranded DNA virus having a genome of about 150 to 160kbp pack¬ aged within an icosahedral nucleocapsid enveloped in a membrane. The membrane includes a number of virus- specific glycoproteins, the most abundant of which are gB, gC, gD and gE, where gB and gD are cross-reactive between types 1 and 2. ■ < It is a matter of great medical and scientific interest to provide safe and effective vaccines against both HSV-1 and HSV-2. One promising approach has been the use of isolated glycoproteins which have been shown to provide protection when injected into mice subsequent¬ ly challenged with live virus. However, the availabil- ity of the Herpes Simplex glycoproteins has heretofore been primarily dependent upon the growth of the virus and the isolation of the membranous proteins. The prob¬ lems of commercial production of the glycoproteins asso¬ ciated with the handling of a dangerous pathogen, the maintenance of the virus in cell culture, the isolation of the glycoproteins free of the viral genome or portions thereof, have substantially precluded the use of the glycoproteins as vaccines. It would therefore be desir¬ able to provide vaccines employing glycoproteins pro- STITUTE SHEET duced by methods other than by growth of the virus and isolation of the membranous proteins. Description of the Prior Art Eberle and Mou, J. of Infectious Diseases (1983) 148:436-444 report the relative titers of anti¬ bodies to individual polypeptide antigens of HSV-1 in human sera. Marsden et al ^ . , J. of Virology (1978) 28_:624-642 report the location of a gene for a 117 kilo- dalton (kd) glycoprotein to lie within 0.35-0.40 map units on the genetic map of HSV by intertypic recombina¬ tion between HSV-1 and HSV-2. Ruyechan et al. , ibid. (1979) 29_:677-697 also report the mapping of glycopro¬ tein B gene to lie between 0.30-0.42 map units. Skare and Summers, Virology (1977) 76_:581-595, report endonu- clease cleavage sites for EcoRI, Xbal and HindiII on HSV-1 DNA. Roizman, Ann. Rev. Genetics (1979) 13:25-57 reports the organization of the HSV genomes. DeLucca et al. , Virology (1982) 122:411 map several phenotypic mutants thought to lie in the gBl structural gene be- tween 0.345 to 0.368 map units. Subunit vaccines extracted from chick embryo cells infected with HSV-1 or HSV-2 are described in U.S. Patents Nos. 4,317,811 and 4,374,127. See also, Hilfenhaus et al. , Develop. Biol. Standard (1982) 52:321-331, where the preparation of a subunit vaccine from a particular HSV-1 strain (B 3) is described. Roizman et al., ibid. (1982) 52 ^ :287-304, describe the preparation of non-virulent HSV-1 x HSV-2 recombinants and deletion mutants which are shown to be effective in immunizing mice. Watson et al., Science (1982) 218:381- 384 describe the cloning and low level expression of the HSV-1 gD gene in E. coli, as well as expression of a cloned fragment by injection into the nuclei of frog oocytes. They also present the nucleotide sequence for the gD gene. Weis et al. , Nature (1983) 302:72-74 re¬ port higher level expression of gD in E. coli. This polypeptide elicits neutralizing antibodies in rabbits. Berman et al. , Science (1983) 222:524-527 report the expression of glycoprotein D in mammalian cell culture. Lasky et al. , Biotechnology (June 1984) 527-532 report the use of this glycoprotein D for the immunization of mice. Cohen et al., J. Virol. (1984) 49_:102-108 re¬ ports the localization and chemical synthesis of a par¬ ticular antigenic determinant of gD, contained within residues 8-23 of the mature protein. Berman et al. , Science (1985) 227:1490-1492 report the use of recombi- nant glycoprotein D for the immunization of guinea pigs. SUMMARY OF THE INVENTION Novel vaccines against Herpes Simplex Virus Types 1 and 2 and methods for their production are provided. These vaccines employ virus specific polypeptides produced by recombinant DNA technology. Particularly, HSV gB and gD were produced in modified yeast hosts and employed as vaccines either separately or in combination. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow diagram of the construction of plasmid pSVl/dhfr. Fig. 2 is a flow diagram of the construction of gB vectors, plasmids pHS112 and pHS114. Fig. 3 represents the construction of plas¬ mids pYHS109 and pYHSHO which carry synthetic sequences gD-A and gD-B, respectively, as described in the Experimental section hereinafter. Fig. 4 is a partial restriction map of the gD region which notes the location of all the gD sequences inserted into yeast expression vectors, as described in the Experimental section hereinafter. Fig. 5 represents the construction of plasmid pYHS115 which carries the naturally-occurring gD gene of HSV-1 under the transcriptional control of the GAPDH promoter and terminator, as described in the Experimen¬ tal section hereinafter. Fig. 6 is a restriction map for the entire HSV-1 genome. Fig. 7 is a detailed restriction map of the subcloned region of the HSV-1 genome. Fig. 8 is a restriction map of a 3.95kb BamHI- Xhol DNA fragment. Fig. 9 is a restriction map for the Hindi11 H fragment of HSV-2 strain 333. Fig. 10 is a detailed restriction map of the pHS203 Xhol subclone. Fig. 11 is a restriction map of glycoprotein B of HSV-2. DESCRIPTION OF THE SPECIFIC EMBODIMENTS Vaccines Vaccines employing recombinant Herpes Simplex Virus glycoprot ins B and D of both Types 1 and 2 are provided. Recombinant Herpes Simplex Virus glycoproteins B and D of both Types 1 and 2 are provided as well, including fragments, precursors and analogs, as well as DNA sequences encoding for the precursors and the mature amino acid sequences and fragments thereof. The frag- ments will be at least about 15 amino acids and prefer¬ ably at least about 30 amino acids in length. In addi¬ tion, constructs are provided for the eukaryotic expres¬ sion of gB and gD in both microorganism and mammalian cells, where the glycoprotein will usually be present without the secretory leader sequence as well as the transmembrane integrator sequence and cytoplasmic C- terminus. The glycoproteins may be used together or separately in vaccines. When used together they may be of the same HSV type or different. They may be used neat, but normally will be used in conjunction with a physiologically acceptable medium, generally water, saline, phosphate buffered saline, sugar, etc., and may be employed with a physiologically acceptable adjuvant, e.g. aluminum hydroxide. The vaccines may be adminis- tered by any convenient route, e.g. intravenously, intra- arterially, subcutaneously, intramuscularly or intra- peritoneally. It may be advantageous to administer split doses of vaccines which may be administered by the same or different routes. Glycoproteins B and D may be used without modification. However when smaller related polypep- tides are used, such as fragments or the like and their molecular weight is less than 5000 daltons, and may be less then 1500 daltons, modification may be required to elicit the desired immune response. The smaller haptens should be conjugated to an appropriate immunogenic carrier such as tetanus toxoid or the like. It may also be possible to link short DNA fragments encoding the gB or gD polypeptides to genes expressing proteins from other pathogenic organisms or viruses. In this way, the resulting fused proteins may provide immunity for more than one disease. The amount of glycoprotein or related polypep- tide employed per dose will usually be about lOμg to 2mg/Kg, more usually about 50μg to lmg/Kg and particu¬ larly about 100 to 500μg/Kg of host body weight. When two sub-units are employed, such as gB and gD, the ratio will usually be about 0.1 to 10:1, more usually about 0.5 to 10:1 and particularly about 0.5 to 5:1. The dose may be administered repeatedly at two to four week intervals, usually not more than about two to three times. Glycoprotein B Table 1 in the Experimental section provides the nucleotide sequence for gBl strain Patton, as well as the amino acid sequence coded by the nucleotide sequence, while Table 2 gives a partial sequence demon¬ strating the substantial homology between gBl and gB2. The nucleotide sequence may be varied in numerous ways. Various fragments may be employed having independent functions, which may be joined to proteins other than the mature gB. In addition, the various codons may be modified so as to encode for the same amino acids, but provide more efficient expression in accordance with the nature of the host. For example, the codons may be modified in accordance with the frequency of occurrence of a particular codon in one or more proteins or groups of proteins, e.g. glycolytic proteins, which contribute to a high proportion of the total proteins of a particu¬ lar host, e.g., yeast. In some instances one or more codons may be modified to code for a different amino acid, substituting one amino acid for another amino acid, where the effect of the change is not detrimental to the immunogenicity of the protein or to other bio¬ logical factors of interest. It may be desirable in some instances to add amino acids to the N- erminus or C-terminus, where such additional amino acids may pro¬ vide for a desired result. This can be readily achieved by providing for additional codons at the 5 1 - or 3'- termini of the sequence encoding the mature gBl or its precursor. In addition, while the amino acid sequence of gB2 may differ from that of gBl by as much as 20 number percent, other strains of HSV-1 or of HSV-2 will have gB glycoproteins the same as or similar to gBl strain Patton or gB2 strain 333, respectively, usually differing by fewer than 5 number percent, more Usually differing by fewer than 2 number percent, and frequently differing by fewer than 0.5 number percent amino acids from the amino acid sequence of gBl strain Patton or gB2 strain 333. The gBl sequence, particularly gBl strain Patton, may be divided into four domains beginning at the N-terminus of the protein: A first hydrophobic region extending from amino acid 1 to about amino acid 56 to 60; a region of variable polarity extending from the first hydrophobic region to about amino acid 750 to 755, particularly 755; a second hydrophobic region extending from said variable polarity region to about amino acid 794 to 800, particularly 794, and a second variable polarity region extending to the C-terminus at amino acid 903. Since gB is a membrane glycoprotein, based on analogy with other glycoproteins, the first hydrophobic region may be considered the signal leader sequence directing secretion and/or membrane location, particu¬ larly since it is followed by a dipeptide arginine- arginine at amino acids 57 and 58, as well as 61 and 62, where the presence of two basic amino acids is known to be a peptidase signal for cleavage. The first se¬ quence of variable polarity would then be external to the membrane and serve as the recognition sequence, to the extent that gB serves as a receptor for another protein or as an immunogen in a vaccine. The second hydrophobic sequence may serve as a transmembrane inte¬ grator sequence (often termed the "anchor"), which can be joined to other amino acid sequences to bind them to a membrane. The second variable polarity amino acid sequence would be expected to be in the cytoplasm and to the extent that a receptor is external to the trans- membrane integrator sequence may serve to modulate one or more cytoplasmic processes. Each of the above sequences may have individual utility as well as utility combined with the other se¬ quences. The first hydrophobic sequence can serve as a signal leader sequence and be joined to DNA sequences coding for unnatural amino acid sequences to provide for transfer from the endoplas ic reticulum through the external membrane, with loss of the signal leader. (By "unnatural" is intended a sequence other than the natu¬ rally occurring sequence associated with an indicated flanking sequence.) In this manner, various proteins, particularly those produced in mammalian host cells can be modified with the signal leader sequence, so as to be secreted from the host cell. The first variable polar region can serve as an immunogen for the produc¬ tion of antibodies capable of neutralizing HSV, as a competitive inhibitor for infection, as a reagent in immunoassays, either labeled or unlabeled, for the de¬ tection of antibodies specific for gB, or the like; the second hydrophobic region can serve to bind a protein, i.e., "anchor" it, to a membrane. Thus, this region can be joined to unnatural proteins, so as to maintain the proteins bound to the membrane. By employing hybrid DNA technology, one can produce a wide variety of sur- face membrane proteins different from the naturally occurring surface membrane proteins. By inserting an unnatural polynucleotide sequence between the first and second hydrophobic regions, and expressing the hybrid polynucleotide in an appropriate host, the unnatural protein can be provided on the surface of the cell. Thus, cells can be modified as to their binding charac¬ teristics for use as reagents in assays, to modify their growth patterns, to act as competitive activators or inhibitors in vivo, and the like. Finally, the second hydrophobic region can be used in conjunction with the transmembrane integrator sequence and sequences encod¬ ing an unnatural polypeptide, where such polypeptide can serve as a receptor and actuate the second variable region to initiate a physiological effect in a host cell. In this manner, cells can be modified to respond to different ligands, as if binding was occurring to the gB protein. It is evident from the above that the entire sequence or fragments thereof having functional signifi- cance can be employed in a variety of ways. The amino acid sequence or fragments thereof can be used by them¬ selves or in combination with various labels in immuno- assays, bioassays or the like, for the detection of HSV or antibodies to HSV, as immunogens, in vaccines, etc. Labels include radionuclides, enzymes, fluorescers, chemiluminescers, enzyme substrates or cofactors, enzyme inhibitors, particles, dyes, etc. These conjugates may be used in any convenient assay, such as enzyme immuno- assays, e.g., ELISA, homogeneous enzyme immunoassays, fluorescence immunoassays, and the like. See, for exam¬ ple, U.S. Patent Nos. 3,766,162; 3,791,932; 3,817,837; 3,996,345 and 4,233,402. The polynucleotide sequence encoding for the precursor to gB or functional fragments thereof may be cloned and expressed by inserting the polynucleotide sequence into an appropriate expression vector and introducing the resulting expression product construct into a compatible host. The coding fragments will be less than about 0.1 map unit, usually less than about 0.05 map " unit. _ The expression vector may be a lo # or high multicopy vector and may provide for secretion or excretion of the polypeptide of interest or retention of the polypeptide of interest in the cytoplasm or in the membrane. A large number of cloning and expression vectors have been published in the literature and are generally available for use in either prokaryotic or eukaryotic hosts, including bacteria, e.g., E. coli, B. subtilis, etc., fungi, particularly yeast, e.g., . cerevisiae, and a wide variety of immortalized mammalian cells, such as mouse cells, monkey cells, hamster cells, e.g., 3T3, Vero, Chinese Hamster Ovary cells (CHO), etc. Depending upon the host, where secretion is de¬ sired, either the native or unnatural secretory leader sequence may be employed. The processing signals for cleavage of the secretory leader may be the natural signals or the signals associated with the unnatural secretory leader or both in tandem. In some instances, the vector may result in integration into the genome of the host. SUBSTITUTE \ For secretion, the polynucleotide sequence will require the first hydrophobic region, while being free of the second hydrophobic region and normally the second variable polar region. For retention in the cytoplasm, the polynucleotide sequence will be free of the sequence coding the secretory leader sequence and may or may not have the second hydrophobic sequence including the second variable polar region. To remove the individual functional sequences or to join a par- ticular functional sequence to an unnatural sequence, the polynucleotide sequence encoding the gB precursor can be restriction mapped and where appropriate restric¬ tion sites are found, the sequence may be cleaved at or near the desired site. Where excess nucleotides exist, these can be removed by resection, for example with Bal31 or where the sequence has been truncated, the lost nucleotides may be replaced by employing chemical¬ ly synthesized adapters. By appropriate choice of adap¬ ters, restriction sequences may be maintained and/or new restriction sequences introduced. In some instances it may be useful to fill in the overhang resulting from restriction employing the Klenow fragment to provide for blunt ends, followed by blunt-end ligation with an appropriate ligase. Selection may then be made for the hybrid DNA having the appropriate orientation. In order to obtain the polynucleotide sequence encoding for gBl-Patton, the location of the gBl coding sequences on the EcoRI restriction fragment F was mapped. Three subfragments of the F fragment were isolated and subcloned into pBR322 (Fig. 7). DNA fragments from these subclones were then used to probe Northern blots of Poly A mRNA isolated from HSV-1 infected cells. Fragments which hybridized to mRNA of the size expected for gB were presumed to lie within the gB coding region. The direction of transcription of gB was also elicited by determining which strand of the DNA probes hybridized with the mRNA. To verify the identity of the gB se- quence, DNA fragments were used to hybrid-select HSV-1 mRNA, which was then translated in vitro and the result- ^ ing proteins analyzed for gB using a gB specific anti- ~ body. The gBl coding fragment may now be manipulated in a variety of ways, including restriction mapping and sequencing, so as to establish the restriction sites and the open reading frame regions for expression. The DNA sequence may then be restricted to provide for a sequence encoding the entire gB precursor or fragments thereof. These sequences may then be inserted into an appropriate expression vector having appropriately posi¬ tioned transcriptional and, as appropriate, translational signals. As previously indicated, this can be achieved by filling in overhangs and providing for blunt-end ligation, by employing adapters, or the like. Of particular interest is to introduce the gene in tandem with a gene capable of amplification. Convenient genes include the dihydrofolate reductase (DHFR) gene, which can be amplified by employing metho- trexate, where the DHFR gene and flanking regions are reiterated; metallothioneins which can be amplified with heavy metals, e.g., copper, or the like. The ex¬ pression product construct can be introduced into an appropriate host by any convenient means, including transformation, transfection, calcium phosphate preci¬ pitation, etc. The host cells may then be stressed with the appropriate biocide at levels which select for amplification of the particular gene. The cells may then be cultured and grown to provide efficient produc¬ tion of the desired polypeptide. Following the procedure described above, the poly¬ nucleotide sequence coding for gB2-333, both precursor and mature, may be isolated, cloned, and manipulated to provide a construct which may result in expression in one or more hosts. However, in view of the availability of fragments coding for gBl-Patton, these fragments may SHEET be used as probes for either localization of gB2 encod¬ ing DNA segments to specific HSV-2 restriction fragment 2. clone(s) or isolation of gB2 mRNA from infected host cells. Conveniently, a plurality of probes may be em- ployed coding for different regions of the gBl gene. One selects for either positive DNA fragments(s) or abundant mRNA having approximately the right size which hybridizes to the probe(s). The mRNA may then be re¬ verse transcribed to provide cDNA or may be used for hybridization to fragments of the HSV-2 genome to con¬ firm their gB2 encoding function. Glycoprotein D Polypeptides which are immunologically cross- reactive with naturally-occurring glycoprotein D are produced in yeast by recombinant DNA methodology. Pro¬ duction in yeast allows the advantages associated with eukaryotic hosts, e.g., post-translational modification and secretion. The polypeptides of the present inven- tion may be produced from relatively short synthetic DNA fragments encoding for at least about nine amino acids to provide haptens useful for eliciting an immune response specific for gD, e.g., for use in vaccine pro¬ duction. The cloned DNA fragments (or the RNA produced therefrom) may also find use as hybridization probes in a variety of applications. Alternatively, much longer DNA fragments, either synthetic or natural, may be used to produce larger polypeptides for use as vaccines, immunogens, immunological reagents, and the like. The peptides of the present invention will find particular use in the preparation of vaccines against infection by Herpes Simplex Virus. The glycoprotein D (gD) DNA fragments of the present invention may be of natural or synthetic origins. The natural gD gene of HSV-1 is located on the viral genome between the short internal repeat (IR S ) sequence and short terminal repeat (TR g ) sequence at the 3'-end thereof. Coding for the mature protein is found on an approximately 1.6kbp fragment located on a 2.9kbp Sacl restriction fragment of the genome. The entire coding region for the mature protein is located within a Hindlll-Nrul fragment of the 2.9kbp Sacl fragment. The naturally-occurring gD gene may be employed with or without modification. Regions of the gene may be de¬ leted and/or joined to other DNA fragments as desired. The preparation, cloning and expression of particular fragments of the naturally-occurring gD gene are de¬ scribed in detail in the Experimental section herein¬ after. Synthetic gD sequences will also find use, either alone or in combination with the naturally- occurring sequences. Coding for the synthetic sequences may be based on published nucleotide sequences for gD found in the literature. See, Watson et al., (1982), supra. The synthetic fragments will be sufficiently long to code for at least nine contiguous amino ' acids with a maximum length equal to that of the naturally- occurring gene or longer. When preparing polypeptides for use as immunological reagents or as vaccines, it is usually desirable that the nucleotide sequence code for an oligopeptide corresponding to an epitopic site of the natural gD protein. Often, such epitopic sites may be predicted by employing the folding rules of Chou and Fasman, Biochemistry (1974) 13:211-222, in conjunction with an analysis of hydrophobic and hydrophilic regions of the protein (Hopp and Woods, Proc. Natl. Acad. Sci. USA (1981) 78:3824-3828). In particular, it has been found that polypeptides corresponding to amino acids 253-283 and 8-23 in the mature naturally-occurring gD protein will cross-react with antisera raised against the natural gD protein. A number of techniques are available for syn¬ thesizing short single-stranded DNA fragments, e.g., the phosphoramidite method described by Beaucage and Carruthers, Tetrahedron Lett. (1981) 22:1859-1862. Short fragments having a length of about 40 bases or less may be synthesized as a continuous single-stranded fragment. The complementary strand may also be syn- thesized, and the two strands annealed under appropriate conditions. Alternatively, the complementary strand may be added using DNA polymerase with an appropriate primer sequence. The synthesis of longer fragments exceeding 100 base pairs is typically accomplished by the prepar¬ ation of a series of single-stranded DNA fragments in¬ cluding from about 10 to 100 bases, usually from about 15 to 60 bases. The sequences of such fragments are selected so that when the fragments are brought to- gether under annealing conditions, a double stranded fragment having the desired nucleotide sequence is produced. When devising such synthetic nucleotide sequences, the sequences of the individual single stranded DNA fragments are examined to assure that annealing of unmatched segments is avoided. In this way, base pairing occurs only between those segments which are intended to be annealed in the resulting double stranded DNA fragment. Undesired base pairing may usually be avoided by altering one nucleotide (usually the third nucleotide) in preselected ones of the codons. When preparing synthetic gD DNA fragments, it may sometimes be desirable to modify the reported nucleotide sequence. For example, it will usually be preferred to use codons which are preferentially recognized by the intended yeast host. Specifically, such codons are those which appear at high frequency in the structural genes encoding for the yeast glycolytic enzymes. The nucleotide sequence will usually comprise at least 50% preferred yeast codons, more usually at least 60%, and preferably at least 75%. In some instances, it may be desirable to further alter the nucleotide sequence to create or remove restriction sites or to substitute one or more amino acids in the resulting polypeptide. Such changes may be made to enhance the immunogenieity of the polypeptide, facili- tate conjugating the polypeptide to a carrier protein, or the like, etc. It may also be desirable at times to add amino acids to the N-terminus or C-terminus of the polypeptide, where such additional amino acids may pro¬ vide for a desired result. The DNA fragments coding for a desired gD fragment will be incorporated in DNA constructs capable of self-replication and expression in yeast. Such DNA constructs will include a replication system recognized by the yeast host, the gD DNA fragment encoding the desired polypeptide product, transcriptional and trans- lational initiation regulatory sequences joined to the 5'-end of the gD sequence, and transcriptional and translational termination regulatory sequences joined to the 3'-end of the gD sequence. The transcriptional regulatory sequences will include a promoter, which may be the promoter associated with the secretory leader and processing signal sequence. Other promoters may also find use, particularly those involved with the enzymes in a yeast glycolytic pathway, such as the promoters for alcohol dehydrogenase, glycer- aldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate kinase, triose phosphate isomerase, phosphoglucoisome- rase, phosphofructokinase, and the like. By employing these promoters with other regulatory sequences, such an enhancers, operators, and the like, and using a host having an intact regulatory system, one can regulate the expression of the gD polypeptide product by varying the carbon source, e.g., replacing glucose with galac- tose; varying the concentration of a nutrient, e.g., phosphate, or changing the temperature with a tempera¬ ture sensitive promotor or regulatory system. The transcriptional termination regulatory sequence will include a terminator, preferably a termi¬ nator balanced with the promoter to provide for proper transcription. Conveniently, the terminator which is naturally found with the promoter may be employed. The remaining sequences in the construct, including the replication systems for both yeast, e.g., 2μ plasmid, and bacteria, e.g., Col El, are well known and amply described in the literature. Enhanced yields of shorter polypeptides may be obtained by employing DNA constructs which include a secretory leader and processing signal sequence to effect secretion and post-translational modification of the gene product in yeast. The upper size limit on the secreted polypeptides is not fixed, although they will usually be below 40 kilodaltons, more usually below about 30 kilodaltons. Moreover, size is not the only determinative criteria as hydrophobic peptides may be more readily secreted than non-hydrophobic peptides. The secretory leader and processing signal sequences will normally be derived from naturally-occurring DNA sequences in yeast which provide for secretion of a polypeptide. Such polypeptides which are naturally secreted by yeast include o^-factor, a-factor, acid phosphatase, and the like. If desired, the naturally- occurring sequence may be modified, for example, by reducing the number of lys-arg pairs which define the processing site (while retaining at least one pair), or by reducing the length of the secretory leader sequence (while retaining sufficient length to provide for se¬ cretion), or by introducing point mutations, deletions or other modifications which facilitate manipulation, e.g., introducing restriction recognition sites. Con¬ veniently, the secretory leader and processing signal sequence may be joined to the gD DNA fragment by provid¬ ing appropriate cohesive ends on the gD fragment, by use of appropriate adaptor molecules, or a combination of both. Polypeptides of the present invention may also be produced intracellularly as follows. After the transformed cell culture has reached a high density, the cells will be separated, typically by centrifugation, lysed, and the gD polypeptides isolated by various tech¬ niques, such as extraction, affinity chromatography, electrophoresis, dialysis and combinations thereof. The polypeptides of the present invention, and fragments thereof, may be employed in a variety of ways. The polypeptides can be employed both as labelled and unlabelled reagents in various immunoassays, bioas- says, and the like, for the detection of HSV or anti¬ bodies to HSV. Suitable labels include radionuclides, enzymes, fluorescers, chemiluminescers, enzyme substrates or co-factors, enzyme inhibitors, particles, dyes, and the like. Such labelled reagents may be used in a va¬ riety of well known assays, such as radioimmunoassays, enzyme immunoassays, e.g., ELISA, fluorescent immunoas¬ says, and the like. See, for example, U.S. Patent Nos. 3,766,162; 3,791,932; 3,817,837; 3,996,345; and 4,233,402. The following examples are offered by way of illustration and not by way of limitation. EXPERIMENTAL Glycoprotein B Materials and Methods. The HSV-1 strain Patton and HSV-2 strain 333 viable stocks are available from Dr. Richard Hyman, Hershey Medical Center, Hershey, Pennsylvania. These viruses can be propagated in Vero cells available from Dr. Evelyn Linnette, Viro Labs, Emeryville, California, or from the American Type Tissue Culture Laboratory, the propagation being performed in accordance with standard procedures. A library of HSV-1 Patton EcoRI DNA fragments cloned in the EcoRI site of the plasmid pACYC184 (Chang and Cohen, J. Bacteriology (1978) 134:1141) can be obtained from Dr. Hyman or be indepen¬ dently prepared in accordance with conventional tech¬ niques. Two HSV-2 333 clones can also be obtained from Dr. Hyman, namely the Hindi11 fragments H and L inserted into the HindiII site of pBR322 (Sutcliffe, Nucleic Acids Research (1978) 5_:2721). Subcloning. Restriction enzymes, T4DNA ligase, E. coli DNA polymerase I Klenow fragment, and other biological reagents were purchased from Bethesda Research Laboratories or other indicated commercial suppliers and used according to the manufacturer's directions. Double-strand DNA fragments were separated on 1% agarose gels and isolated by electroelution. Isolation of RNA, Northern blot analysis and hybrid- selected translation. Total RNA was prepared from HSV-1 infected Vero cells at 6 ->hrs after infection. Cell monolayers were washed, incubated with extraction buffer and processed as described (Pachl et al., Cell (1983) 33_:335-344). Poly A RNA was prepared by passing total RNA over a 3ml column of oligo dT cellulose (obtained from Collaborative Research) in 500mM NaCl, lOmM Tris HCl pH 7.5, ImM EDTA, 0.1% SDS, then washing the column in lOOmM NaCl, lOmM Tris HCl pH 7.5, ImM EDTA, 0.1% SDS and then eluting the poly A with lOmM Tris HCl pH 7.5, ImM EDTA, 0.1% SDS. For Northern blot analysis, poly A RNA was denatured with glyoxal (McMaster et al., Proc. Natl. Acad. Sci. USA (1977) 74:4835-4838, fractionated by electrophoresis on 1% agarose gels, transferred to nitrocellulose paper (Thomas, ibid. (1980) 77:5201-5205) and hybridized with 32P-labeled probes. The details of the methods used for hybrid- selected translation have been described previously SHEET (Pachl et al.. Cell (1983) 33_:335-344). DNA filters were prepared using either 3μg of a 3.5kb Xho-Kpn frag¬ ment encoding gB or 2μg of a 3.0kb Sstl-Sstl fragment encoding HSV-1 glycoprotein gD. The filters were inc ' u- bated with 40μg of poly A + RNA from HSV-1 infected cells. Bound RNA was eluted and translated in a reticulocyte cell-free system (Pachl et al. , J. Virol. (1983) 45:133- 139). Translation products were analyzed on 12.5% sodium dodecyl sulfate (SDS) polyacrylamide gels (Laemmli, Nature (1970) 227:680). In vivo labeling of cells and immunoprecipitation. To label with 35S-methionme, cells were grown to confluency in 3.5cm dishes, washed once with PBS (0.14M NaCl, 2.7mM KC1, 15.3mM Na 2 HP0 4 , 1.5mM KH 2 0 4 ) and then 0.5ml of labeling media, DME (Dulbecco's Modi¬ fied Eagle medium from Gibco, cat. no. 188G) without ethionine plus 1% dialyzed fetal calf serum and 400μCι/ml 35S-methionme (>1000Cι/mmole) was added per dish. The cells were incubated for appropriate times » at 37°C. At the end of the labeling period, the media was removed and the monolayer washed once with PBS. For a "cold" methionine chase, the .labeling media was replaced with DME containing 2.5mM methionine. For immune precipitation, cells were lysed in 0.1ml of lysis buffer: 20mM Tris-HCl pH8, lOOmM NaCl, ImM EDTA, 0.5% Nonidet P40, 0.5% sodium deoxycholate, bovine serum albumin, 0.1% SDS, l.OmM phenylmethylsulfonyl fluoride, lOmM benzamidine, 1% aprotenin obtained from Sigma Chem¬ ical Company. The cell lysate was scraped into tubes, briefly vortexed, and then held at 4°C for 5-10min. Cell debris was removed by centrifugation and the clari¬ fied lysate stored at -70°C. For immunoprecipitations, cell lysates, 0.1ml, were precleared by incubation with normal serum for 30min at 4°C, then 50μl of a 20% solution of protein A Sepharose (PAS) (in lysis buffer) was added and incuba- T tion continued for 30min at 4°C with gentle rocking. _ The PAS was removed by centrifugation for Imin at 14,000xgl and 5μl of HSV-1 polyclonal antibody (obtained from *** DAKO) or a gB-specific monoclonal antibody F3AB (obtained from Dr. John Oakes, University of South Alabama) was added. When the F3AB antibody was used, 0.1% SDS was omitted from the lysis buffer. After 30min at 4°C, 75μl of PAS was added and incubated as above. PAS-immune complexes were collected by centrifugation, washed 3x with lysis buffer lacking BSA and protease inhibitors and once with 0.12M Tris HCl pH 7.0. Immune precipitated proteins were released from PAS by boiling in SDS sample buffer, followed by analysis on 12% polyacrylamide gels. For immune precipitation of labeled proteins from cell media, the media was first clarified by centrifugation and then 1/10 volume of lOx lysis buffer was added and proteins were precipitated as described above. Immunofluorescence. To analyze gB synthesis in CHO clones, cells, grown in slide wells, were washed 3x with PBS, fixed with 100% methanol at -20°C for lOmin followed by 3 more PBS washes and one wash with PBS plus 5% goat serum (GS). The fixed cells were then incubated with the primary antibody, HSV-1 polyclonal diluted 1/100 in PBS-5% GS, for 30min at 37°C. The cells were then washed 3x in PBS-5% GS and then incubated at 37°C for 30min with the second antibody, FITC-conjugated goat anti-rabbit IgG (Cappel), diluted 1/10 in PBS-5% GS. After 4 washes in PBS-5% GS, the slides were mounted with coverslips using 50% glycerol—lOOmM Tris HCl, pH 8 and observed in a Leitz microscope equipped with epi- fluorescent optics. Live cell immunofluorescence was carried out as described above except that the cells were initially washed once in PBS-5% GS directly fol- lowed by incubation with the first antibody. Before mounting with coverslips, the live cells were fixed EET with 5% formaldehyde in PBS. The fluorescein stained cells were photographed using Kodak Ektachrome film (ASA 400). Cells and tissue culture. The dhfr deficient CHO cell line was obtained from Dr. Y.W. Kan, (University of California at San Francisco). This cell line was originally described by Urlaub and Chasin, Proc. Natl. Acad. Sci. USA (1980) 77:4216-4220. For non-selective conditions, these cells were grown in Ham's F-12 medium (available from Gibco, cat. no. 176) supplemented with 10% fetal calf serum, lOOU/ml penicillin, lOOμg/ml streptomycin and 150μg/ml L-proline. Selective media was DME supplemented with 10% dialyzed fetal calf serum plus penicillin, strepto- mycin and 150μg/ml L-proline. For methotrexate (MTX) selection, concentrated MTX stocks were prepared from MTX obtained from Lederle and added to the above DME selective media immediately before use. DNA transfections. Transformation of dhfr deficient CHO cells with plasmids pSVl/dhfr, pHS112 and pHS114 was carried out using the procedure of van der Eb and Graham (Methods in Enz. (1980) 6_5:826-839), as modified by Parker and Stark, (J. of Virol. (1979) 31:360-369), except that carrier DNA was omitted. A calcium phosphate precipi¬ tate of plasmid DNA was prepared ' by mixing an equal volume of plasmid DNA, in 250mM CaCl 2 , with an equal volume of 2x concentrated HEPES-buffered saline (2xHBS) added dropwise (lxHBS is 0.14M NaCl, 5mM KCl, 0.7mM Na 2 HP0 4 , 2.8mM glucose, lOmM HEPES pH 7.0). After about 20min incubation at room temperature, 1ml of the cal- cium-phosphate-DNA suspension (containing 15μg DNA) was added to the media of cells, grown to 50% confluency on 10cm plates. After 6-8 hrs the DNA containing media was removed and the cells were incubated with 15% glyc- erol-lxHBS for 4min. The cells were then grown in non- selective media (F12) for two days, after which the cells were split, i.e., subcultured, into selective media. Colonies of dhfr positive cells appeared after 10 days and were isolated after 14 days by removing the cells of a colony from a dish with a Pasteur pipette. The isolated cells were transferred to multiwell dishes for propagation. Isolation, cloning and characterization of the gBl gene. To isolate the gene for the glycoprotein gBl, DNA fragments spanning map coordinates 0.345 to 0.40 within the EcoRI F restriction fragment of the HSV-1 strain Patton (Skare and Summers, Virology (1977) 7_6_:581-595) were subcloned in the plasmid pBR322. These fragments were prepared from the appropriate restriction digests of the EcoRI F region in the plasmid pACYC184, separated by electrophoresis on a 1% agarose gel in TAE buffer (0.04M Tris-acetate, 0.002M EDTA) and electroeluted as noted above. * The isolated fragments were ligated into pBR322 which had also been previously cut with the appropriate restriction enzyme and treated with alkaline phosphatase. A restriction map for the entire HSV-1 genome is shown in Fig. 6, and a more detailed map of the region which was subcloned is shown in Fig. 7. Referring to Fig. 6, the conven¬ tional map is shown in the first two lines (Roizman, 1979). The dotted line indicates the L-S junction. The restriction enzyme cleavage map for EcoRI for the prototype isomer arrangement is shown in the third line (Skare and Summers, 1977; Roizman, 1979) with the EcoRI fragment F denoted by the cross-hatched box. For HSV-2, the Hindi11 restriction map is shown in line 4 (Roizman, 1979) with the Hindi11 fragment H cross-hatched. One map unit corresponds to 98.9 megadaltons or 148.9kbp of DNA for HSV-1 and 105.6 megadaltons or 160.5kbp of DNA for HSV-2. Referring to Fig. 7, the restriction enzyme sites shown in the detailed map line (I) are E, EcoRI; B, BamHI; S, Sail; P, Pstl; X, Xhol from DeLucca et al. , 1983; N, Ndel; Xn, Xmnl; V, EcoRV. The BstEII site mapped by DeLucca et al. at 0.355 is missing in this strain and there is a new Pstl site at 0.357. Line II shows three plasmid subclones which encompass the gBl coding region. They are pHS106, which extends from the BamHI site at 0.345 to the Sail site at 0.360; pHS107 which extends from the Sail site at 0.36 to the Sail site at 0.388; and pHS108 which is a BamHI fragment ex¬ tending from 0.345 to 0.40 map units. Line III indicates three probes used for mRNA mapping of gBl; line IV indi¬ cates the fragment used for hybrid selection; and line V shows those probes used to locate the gB2 gene (see be¬ low). The additional restriction sites used to generate these fragments are Nc, Ncol; K, Kpnl; and A, Alul. To locate the gBl coding region within the EcoRI F .fragment, Northern blots of poly A mRNA isolated from HSV-1 infected Vero cells were probed with the DNA fragments indicated on the detailed map isolated from plasmids pHS106 and pHS107. When HSV-1 mRNA was probed with a 0.56kb Pstl-Sall fragment isolated from pHS106, a 3kb mRNA was the major species detected. When the same blot was probed with a 0.49kb Ncol fragment, which maps about lkb upstream from the Pstl-Sall fragment, hybridization to a 3kb mRNA, the presumptive gBl mRNA was also detected. This suggests that the gBl coding sequences extend at least lkb to the left of the Pstl-Sall fragment. The 3kb mRNA does not extend beyond the first Xhol site downstream from the Pstl-Sall fragment, since the 0.5kb Xhol-Xhol fragment does not hybridize to this mRNA. The direction of transcription of the gBl transcription unit is right to left (3' * ■ 5') as evidenced by hybridization of only the 5' →* 3' oriented strands of the Pstl-Sail and Ncol-Ncol fragments (cloned in M13) to the 3kb gBl mRNA. Hybrid selected translation was performed by hybridizing HSV-1 poly A + mRNA with a 3.2kb Kpnl-Xhol fragment, which encompasses the region indicated as encoding gBl. When the bound mRNA was eluted and translated in vitro, a lOOkd protein, similar in size to gBl from HSV-1 infected Vero cells, was detected. Confirmation of the identity of the lOOkd protein was achieved by immunoprecipitation with a gBl-specific monoclonal antibody. Several other proteins were also detected by hybrid selection using the Kpnl-Xhol fragment, probably the result of non-specific hybridization of mRNAs due to the high G+C content of the DNA. A similar pattern of proteins was seen when the same RNA was selected with a 3.0kb Sstl-Sstl DNA fragment encoding HSV-1 glycoprotein gD, except that the lOOkd gB protein was not detected. This result indicates that gB is specific to the Xhol-Kpnl fragment. Fig. 8 is a restriction map of a 3.95kb DNA fragment, which extends from a BamHI restriction site at 0.345 to an Xhol site at 0.373 map units. The open reading frame for gBl is indicated by the box and the direction of transcription is from right to left as shown. The actual coding region covers map units 0.348 to 0.367. The DNA sequence from the BamHI site to a * non-unique Alul site at nucleotide number 3640 is shown with the Alul site indicated by the (A). The restric¬ tion sites shown include B, BamHI; Bl, Ball; Bs, BstEII; K, Kpnl; Nc, Ncol; P, Pstl; Pv, PvuII; S, Sail; Sc, Sacl; X, Xhol; Xm, Xma3. Restriction sites are not shown for the right-hand end from the Alul site to the terminal Xhol site. Three probes used for mapping the gB2 gene and potential glycosylation sites and hydro- phobic anchor and signal regions (solid box) in the product gBl protein are noted. The DNA sequence was determined from the BamHI site to a non-unique Alul site at nucleotide residue number 3640. The DNA sequence was determined using the M13 dideoxynucleotide synthesis method of Sanger from both DNA strands across the coding region. The DNA sequence was obtained from overlapping restric¬ tion fragments such that the sequence was read across all restriction fragment joints. The following Table 1 is the sequence for the above-indicated DNA fragment, with the derived amino acid sequence for gBl. SUBSTITUTE SHEET 26 Table 1 AGCTCGCCCGGTTCATCATGGGGGCGGGGCGCTCGGGTGCTCATTGGGCCGTCAGCCAA 50 TTTCAGAGGTTTTACTGTTTTGACGGCATTTCCGGAATAACGCCCACTCAGCGCGCCGC 100 CTCGCGATATATTCGCGAGCTGATTATCGCCACCACACTCTTTGCCTCGGTCTACCGGT 150 GCGGGGAGCTCGAGTTGCGCCGCCCGGACTGCAGCCGCCCGACCTCCGAAGTCGTTACC 200 GTTACCCGCCCGGCGTATATCTCACGTACGACTCCGACTGTCCGCTGGTGGCCATCGTC 250 GAGAGCGCCCCCGACGGCTGTATCGGCCCCCGGTCGGTCGTGGTCTACGACCGAGACGT 300 TTTCTCGATCCTCTACTCGGTCCTCCAGCACCTCGCCCCCAGGCTACCTGACGGGGGGC 1.00 1 met arg gin gly ala pro ala arg ACGACGGGCCCCCGTAGTCCCGCC ATG CGC CAG GGC GCC CCC GCG CGG •-.50 10 20 gly cys arg trp phe val val trp ala leu leu gly leu thr leu GGG TGC CGG TGG TTC GTC GTA TGG GCG CTC TTG GGG TTG ACG CTG 500 30 - - gly val leu val ala ser ala ala pro ser ser pro gly thr pro GGG GTC CTG GTG GCG TCG GCG GCT CCG AGT TCC CCC GGC ACG CCT 550 -40 50 gly val ala ala ala thr gin ala ala asn gly gly pro ala thr GGG GTC GCG GCC GCG ACC CAG GCG GCG AAC GGG GGC CCT GCC ACT ; 60 pro ala pro arg arg pro trp arg arg pro asn gly gly pro glu CCG GCG CCG CGC CGC CCT TGG CGC CGC CCC AAC GGG GGA CCC GAA 600 70 80 thr glu glu glu gin lys thr glu lys pro asn ala ala thr pro ACC GAA GAA GAA CAA AAA ACC GAA AAA CCC AAC GCC GCC ACG CCC 650 90 arg arg arg gin arg asp arg arg arg gly pro arg his pro ala CGC CGG CGA CAA CGC GAC CGT CGC CGC GGG CCA CGC CAC CCT GCG 700 100 110 arg ala leu arg asp ile lys ala glu asn thr asp ala asn phe CGA GCA CTG CGG GAC ATC AAG GCG GAG AAC ACC GAT GCA AAC TTT 750 120 tyr val cys pro pro pro thr gly ala thr val val gin phe glu TAC GTG TGC CCA CC CCC ACG GGC GCC ACG GTG GTG CAG TTC GAG 800 gin pro arg arg cys pro thr arg pro glu gly gin asn tyr thr CAG CCG CGC CGC TGC CCG ACC CGG CCC GAG GGT CAG AAC TAC ACG 850 27 150 glu gly ile ala val val phe lys glu asn ile ala pro tyr lys GAG GGC ATC GCG GTG GTC TTC AAG GAG AAC ATC GCC CCG TAC AAG 900 160 170 phe lys ala thr met tyr tyr lys asp val thr val ser gin val TTC AAG GCC ACC ATG TAC TAC AAA GAC GTC ACC GTT TCG CAG GTG 950 180 trp phe gly his arg tyr ser gin phe met gly ile phe glu asp TCG TTC GGC CAC CGC TAC TCC CAG TTT ATG GGG ATC TTT GAG GAC 1000 190 200 arg ala pro val pro phe glu glu val ile asp lys ile asn ala CGC GCC CCC GTC CCC TTC GAG GAG GTG ATC GAC AAG ATC AAC GCC 210 lys gly val cys arg ser thr ala lys tyr val arg asn asn. leu ' AAG GGG GTC TGT CGG TCC ACG GCC AAG TAC GTG CGC AAC AAC CTG 1050 220 230 glu thr thr ala phe his arg asp asp his glu thr asp met glu GAG ACC ACC GCG TTT CAC CGG GAC GAC CAC GAG ACC GAC ATG GAG 1100 2-.0 leu lys pro ala asn ala arg asp pro,.his glu pro gly leu ala CTG AAA CCG GCC AAC GCC CGC GAC CCG CAC GAG CCG GGG CTG GCA 1150 250 260 his his arg pro gin val gin pro leu ala gly gly gly val pro CAC CAC CGA CCT CAA GTA CAA CCC CTC GCG GGT GGA GGC GTT CCA 1200 270 pro val arg thr thr val asn cys ile val glu glu val asp ala CCG GTA CGG ACG ACG GTA AAC TGC ATC GTC GAG GAG GTG GAC GCG 1250 280 290 arg ser val tyr pro tyr asp glu phe val leu ala thr gly asp CGC TCG GTG TAC CCG TAC GAC GAG TTT GTG CTG GCG ACT GGC GAC 1300 300 phe val tyr met ser pro phe tyr gly tyr arg glu gly ser his TTT GTG TAC ATG TCC CCG TTT TAC GGC TAC CGG GAG GGG TCG CAC 1350 310 320 thr glu his thr ser tyr ala ala asp arg phe lys gin val asp ACC GAA CAC ACC AGC TAC GCC GCC GAC CGC TTC AAG CAG GTC GAC 1*400 330 gly phe tyr ala arg asp leu thr thr lys ala arg ala thr ala GGC TTC TAC GCG CGC GAC CTC ACC ACC AAG GCC CGG GCC ACG GCG 1-.50 3*40 350 pro thr thr arg asn leu leu thr thr pro lys phe thr val ala CCG ACC ACC CGG AAC CTG CTC ACG ACC CCC AAG TTC ACC GTG GCC 28 360 trp asp trp val pro lys arg pro ser val cys thr met ihr lys TGG GAC TGG GTG CCA AAG CGC CCG TCG GTC TGC ACC ATG ACC AAG 1500 370 380 trp gin glu val asp glu met leu arg ser glu tyr gly gly ser TGG CAG GAG GTG GAC GAG ATG CTG CGC TCC GAG TAC GGC GGC TCC 1550 390 phe arg phe ser ser asp ala ile ser thr thr phe thr thr asn TTC CGA TTC TCC TCC GAC GCC ATA TCC ACC ACC TTC ACC ACC AAC 1600 noo --no leu thr glu tyr pro leu ser arg val asp leu gly asp cys ile CTG ACC GAG TAC CCG CTC TCG CGC GTT GAC CTG GGG GAC TGC ATC 1650 H20 gly lys asp ala arg arg his gly pro his leu arg pro gin tyr GGC AAG GAC GCC CGA CGC CAT GGA CCG CAT CTT CGC CCG CAG TAC 1700 -130 WO asn ala thr his ile lys val gly gin pro gin tyr tyr leu ala AAC GCG ACG CAC ATC AAG GTG GGC CAG CCG CAG TAC TAC CTG GCC 1750 -.50 asn gly gly phe leu ile ala tyr gin pro leu leu ser asn thr AAT GGG GGC TTT CTG ATC GCG TAC CAG CCC CTT CTC AGC AAC ACG 1800 •.60 -.70 leu ala glu leu tyr val arg glu his leu arg glu gin ser arg CTC GCG GAG CTG TAC GTG CGG GAA CAC CTC ' CGA GAG CAG AGC CGC 1850 480 lys pro pro asn pro thr pro pro pro pro gly ala ser ala asn AAG CCC CCA AAC CCC ACG CCC CCG CCG CCC GGG GCC AGC GCC AAC 1900 1»90 500 ala ser val glu arg ile lys thr thr ser ser ile glu phe ala GCG TCC GTG GAG CGC ATC AAG ACC ACC TCC TCC ATC GAG TTC GCC 510 arg leu gln phe thr tyr asn his ile gin arg his val asn asp CGG CTG CAG TTT ACG TAC AAC CAC ATA CAG CGC CAT GTC AAC GAT 1950 520 530 met. leu gly arg val ala ile ala trp cys glu leu gin asn his ATG TTG GGC CGC GTT GCC ATC GCG TGG TGC GAG CTG CAG AAT CAC 2000 50 lys leu thr leu trp asn glu ala arg lys leu asn pro asn ala AAG CTG ACC CTG TGG AAC GAG GCC CGC AAG CTG AAC CCC AAC GCC 2050 550 560 • ile ala ser ala thr val gly arg arg val ser ala arg met leu i ATC GCC TCG GCC ACC GTG GGC CGG CGG GTG AGC GCG CGG ATG CTC 2100 29 570 gly asp val met ala val ser thr cys val pro val ala ala asp GGC GAC GTG ATG GCC GTC TCC ACG TGC GTG CCG GTC GCC GCG GAC 2150 580 590 asn val ile val gin asn ser met arg ile ser ser arg pro gly AAC GTG ATC GTC CAA AAC TCG ATG CGC ATC AGC TCG CGG CCC GGG 2200 600 ala cys tyr ser arg pro leu val ser phe arg tyr glu asp gin GCC TGC TAC AGC CGC CCC CTG GTC AGC TTT CGG TAC GAA GAC CAG 2250 610 620 gly pro leu val glu gly gin leu gly glu asn asn glu leu arg GGC CCG TTG GTC GAG GGG CAG CTG GGG GAG AAC AAC GAG CTG CGG 2300 630 leu thr arg asp ala ile glu pro cys thr val gly his arg arg CTG ACG CGC GAT GCG ATC GAG CCG TGC ACC GTG GGA CAC CGG CGC 2350 6*40 650 tyr phe thr phe gly gly gly tyr val tyr phe glu glu ser ala TAC TTC ACC TTC GGT GGG GGC TAC GTG TAC TTC GAG GAG TCA GCG 660 tyr ser his gin leu ser arg ala asp ile thr thr val ser thr TAC TCC CAC CAG CTG AGC CGC GCC GAC ATC ACC ACC GTC AGC ACC 2*400 \ 670 680 phe ile asp leu asn ile thr met leu glu asp his glu phe val TTC ATC GAC CTC AAC ATC ACC ATG CTG GAG GAT CAC GAG TTT GTC 2*450 690 pro leu glu val tyr thr arg his glu ile lys asp ser gly leu CCC CTG. GAG GTG TAC ACC CGC CAC GAG ATC AAG GAC AGC GGC CTG 2500 700 710 leu asp tyr thr glu val gin arg arg asn gin leu his asp leu CTG GAC TAC ACG GAG GTC CAG CGC CGC AAC CAG CTG CAC GAC CTG 2550 720 arg phe ala asp ile asp thr val ile his ala asp ala asn ala CGC TTC GCC GAC ATC GAC ACG GTC ATC CAC GCC GAC GCC AAC GCC 2600 730 ^0 ala met phe ala gly leu gly ala phe phe glu 'gly met gly asp GCC ATG TTC GCG GGC CTG GGT GCG TTT TTC GAG GGG ATG GGC GAC 2650 750 leu gly arg ala val gly lys val val met gly ile val gly gly CTG GGG CGC GCG GTC GGC AAG GTG GTG ATG GGC ATC GTG GGC GGC 2700 760 770 val val ser ala val ser gly val ser ser phe met ser asn pro GTG GTA TCG GCC GTG TCG GGC GTG TCC TCC TTC ATG TCC AAC CCC 2750 30 780 phe gly ala leu ala val gly leu leu val leu ala gly leu ala TTT GGG GCG CTG GCC GTG GGT CTG TTG GTC CTG GCC GGC CTG GCG 2800 790 800 ala ala phe phe ala phe arg tyr val met arg leu gin ser asn GCG GCC TTC TTC GCC TTT CGC TAC GTC ATG CGG CTG CAG AGC AAC 810 pro met lys ala leu tyr pro leu thr thr lys glu leu lys asn CCC ATG AAG GCC CTG TAC CCG CTA ACC ACC AAG GAG CTC AAG AAC 2850 820 830 pro thr asn pro asp ala ser gly glu gly glu glu gly gly asp CCC ACC AAC CCG GAC GCG TCC GGG GAG GGC GAG GAG GGC GGC GAC 2900 8*40 phe asp glu ala lys leu ala glu ala arg glu met ile arg tyr TTT GAC GAG GCC AAG CTA GCC GAG GCC CGG GAG ATG ATA CGG TAC 2950 850 860 met ala leu val ser ala met glu arg thr glu his lys ala lys ATG GCC CTG GTG TCT GCC ATG GAG CGC ACG GAA CAC AAG GCC AAG 3000 870 lys lys gly thr ser ala leu leu ser ala lys val thr asp met AAG AAG GGC ACG AGC GCG CTG CTC AGC GCC AAG GTC ACC GAC ATG 3050 880 890 val met arg lys arg arg asn thr asn tyr thr gin val pro asn GTC ATG CGC AAG CGC CGC AAC ACC AAC TAC ACC CAA GTT CCC AAC 3100 900 903 lys asp gly asp ala asp glu asp asp leu OP AAA GAC GGT GAC GCC GAC GAG GAC GAC CTG TGA CGGGGGGTTTGTTGTAAA 3150 TAAAAACCACGGGTGTTAAACCGCATGTGCATCTTTTGGTGTGTTTGTTTGGTACGCCTT 3200 TTGTGTGTGTGGGAAGAAAGAAAAGGGAACACATAAACTCCCCCGGGTGTCCGCGGCCTG 3250 TTTCCTCTTTCCTTTGCCCGTGACAAAACGGACCCCCTTGGTCAGTGCCGATTCCCCCCC 3300 ACGCCTTCCTCCACGTCGAAGGCTTTTGCATTGTAAAGCTACCCGCCTACCCGCGCCTCC 3350 3400 CAATAAAAAAAAAGAACATACACCAATGGGTCTTATTTGGTATTACCTGGTTTATTTAAA 3450 AAGATATACAGTAAGACATCCCATGGTACCAAAGACCGGGGCGAATCAGCGGGCCCCCAT 3500 CATCTGAGAGACGAACAAATCGGCGGCGCGGGCCGTGTCAACGTCCACGTGTGCTGCGCT 3550 GCTGGCGTTGACAAGGCCCCGGCCTCCGCGTTGGATGCCTCCGGTTGGGATCC 3600 Primer extension, using a 22bp oligonucleotide (residues 473-494) indicated that the 5'-end of gB mRNA was located at residue 188. The CAT and TATA transcrip¬ tional regulatory signals are presumptively at residues 55-62 and 125-131. Starting at the ATG at residues 438-440, there is an open reading frame of 2709 nucleo¬ tides which terminates at a TGA stop codon. Two pre¬ sumptive polyadenylation signals are located in a 3'- non-coding region at residues 3166-3173 and 3409-3416. The protein gB has a high proline content which is con¬ sistent with that observed for HSV glycoproteins gC and gD. The observed amino acid sequence is character¬ istic of a membrane protein. There is a very hydropho- bic region near the carboxy terminus stretching from amino acid residue number 755 to 794, a 40-amino acid sequence which may span the membrane. At the N-terminus the first 56 amino acids are primarily hydrophobic, there being no charged residues from residues 11 to 56. This hydrophobic amino acid domain precedes a region with a high concentration of charged or hydrophilic • amino acids. The hydrophobic sequence at the N-terminus may serve as a secretory leader or signal sequence fol¬ lowed by processing signals for cleavage and removal of the secretory leader. The hydrophobic region near the C-terminus can serve as a transmembrane integrating sequence for binding the protein to the cell membrane. There are eight possible N-'linked glycosylation sites as defined by the sequence asn-X-thr/ser (see also Fig. 8). If the first 56 amino acids are removed by processing and each of the potential N-linked glycosyla¬ tion sites are utilized with the addition of an average 2kd of carbohydrate per site, the molecular weight of the mature protein would be approximately llOkd. Expression of gBl in mammalian cells. Employing the above DNA sequence or fragment thereof, expression was achieved as follows. The vector employed is a mammalian expression vector, referred to as pSVl/dhfr. This 5.63kb plasmid contains 2.8kb of E. coli plasmid pBR328 sequences, including the ampicil- lin-resistance β-lactamase gene and the origin of rep¬ lication. The vector also contains a selectable mam¬ malian cell marker, the mouse dihydrofolate reductase cDNA gene (dhfr) (Nuhberg et al. , Cell (1980) 19_:355) linked to the SV40 early promoter, which directs the transcription of dhfr. Additional SV40 sequences, in¬ cluding t antigen splice donor and splice acceptor sites and the polyadenylation sites for early transcripts, are included downstream from the dhfr gene within a 1.65kb Bglll-EcoRI fragment. The plasmid pSVl/dhfr was constructed by first isolating the 0.4kb BamHI-HindiII fragment encoding the SV40 origin and early promoter from plasmid pSVgtl. This SV40 fragment was then inserted into plasmid pBR328 by substituting this fragment for the small Hindlll- BamHI fragment of pBR328. The dhfr cDNA gene and the SV40 splice sites and poly A sites of pSVl/dhfr were derived from plasmid pSV2/dhfr (Mulligan and Berg, Mol. Cell Biol. (1981) 1:854-864). The 2.4kb HindiII-RI fragment encoding the dhfr-SV40 sequences was excised from pSV2/dhfr and inserted into the above pBR328 plas¬ mid by substitution for the small HindiII-RI fragment of pBR328. The details of these construction are given in Fig. 1. To obtain expression of gBl, two pSVl/dhfr-gB plasmids, pHS112 and pHS114 were constructed. (Fig. 2.) pSVl/dhfr was restricted with Bglll and HindiII excising the dhfr cDNA fragment. The resulting frag- ments are then blunt-ended by filling in the overhangs with the Klenow fragment of DNA polymerase I. A Xhol- Kpnl HSV-1 fragment containing the gB gene is isolated UTE SHEET from pHS108. A portion is taken and partially digested with PvuII to generate a DNA sequence lacking the 3'- anchor region. The resulting truncated gBl gene lacks 580bp from the 3'-end of the gene. Both fragments are then blunt-ended with the Klenow fragment of pol I. Each gB blunt-ended fragment is ligated into the BglII-HindiII restricted pSVl/dhfr vector to provide two sets each of constructs, with the gBl gene in oppo¬ site orientations. The orientations having the Xhol generated terminus proximal to the SV promoter, with the direction of transcription being from the SV promo¬ ter to the SV splice sites are selected and designated pHSlll and pHS113 for the complete and truncated gBl genes, respectively. The two plasmids are then com- pletely digested with EcoRI and partially digested with BamHI to provide a cassette which includes the SV promo¬ ter, the gB gene and the SV splice and polyadenylation sites. These fragments are blunt-ended and-ligated into EcoRI digested pSVl/dhfr vectors, so as to have the gBl gene downstream from the dhfr gene * and in the same orientation. The complete gBl gene and truncated gBl plasmid constructs are designated pHS112 and pHS114, respectively. The plasmids are then transfected into Chinese hamster ovary (CHO) cells deficient in dhfr using the calcium phosphate precipitation method as described in Materials and Methods. Transfected cells are selected by employing a selective medium lacking thymidine, pu- rines and glycine. Cells were isolated by removal with a Pasteur pipette and propagation in multiwell plates. A number of clones were isolated which were shown to pro¬ duce gB by immunofluorescence and radioimmunoprecipita- tion employing a HSV-1 polyclonal antibody or a mono¬ clonal antibody specific for gB. Three cell clones, pHS112-l, pHS112-9 and pHS112-23, were isolated which synthesize an intracellular form of the- complete gB protein. The gB made in these cells appears to be SUBSTITUTE SHEET glycosylated, since higher molecular weight forms can be detected after a one hour pulse, followed by a 5 hr chase, as compared to non-chased cells and about 10% of the gB is secreted into the media. Five cell clones (pHS114-5, pHS114-6, pHS114-7, pHS114-ll and pHS114-12) expressing the truncated gB were also analyzed and shown to also secrete some gB into the media. One of these cell lines, pHS114-7, was chosen for further amplifica¬ tion with MTX. Clones were initially selected at 0.01, 0.05, 0.10 and 0.3μM MTX. Three clones synthesizing high levels of gB, as detected by immunofluorescence, were isolated from the 0.3μM MTX selections. By radio- immune precipitation, these clones, pHS114-0.3μM-6, 23 and 25, synthesize 2-3 times more gB during a lhr label- 35 . . . mg with S-methionme than the unamplified clone, pHS114-7. Pulse chase experiments indicate that at least 50% of the gB synthesized in these clones during a lhr pulse is secreted extracellularly by 5hr. Expression of gBl in yeast. Yeast expression was developed as follows: Partial N-terminal amino acid analysis of isolated gBl was found to have glu, ala, and ala for amino acids 2, 5 and 11, indicating that the N-terminal region of the mature protein was at amino acid 151 of the sequence described previously (after the MboII site). A cassette was prepared employing the glycer- aldehyde-3-phosphate-dehydrogenase promoter region and terminator region. A yeast gene library was prepared by inserting fragments obtained after partial digestion of total yeast DNA with restriction endonuclease Sau3A in lambda-phage Charon 28 (Blattner et al. , Science (1977) 196:161-169). The phage library was screened with DNA complementary to the yeast GAPDH mRNA and the yeast GAPDH gene from one of these clones was subcloned as a 3.5kb BamHI fragment in the BamHI site of pBR322 (pGAP-2). The GAPDH promoting-active fragments were SUBSTITUTE SHEET isolated from these clones. A Hhal-Hindlll fragment of about 350bp containing the 3' portion of the promoter was obtained by: a) digestion of pGAP-2 with Hinfl to generate an approximately 500bp segment which includes the 3' part of the promoter and a region encoding the N-terminal amino acids of GAPDH; b) resection with Bal31 to yield a 400bp fragment lacking the GAPDH coding re¬ gion (3'-terminus 1 base upstream from the ATG initiator codon); c) addition of HindiII linkers; and d) cleavage with Hhal. A Hindlll-Hhal fragment of about 700bp con¬ taining the 5' portion of the promoter was ligated to the 350bp Hhal-HindiII fragment and treated with HindiII. The resulting l,061bp HindiII fragment was isolated by gel electrophoresis and cloned in pBR322 (pGAP-347). The GAPDH promoter fragment in pGAP347 was isolated by cleavage with BamHI (within the 5' pBR322 flanking re¬ gion) and partially with HindiII (at the 3' end of the promoter fragment) to provide a l,407bp fragment con¬ taining a l,061bp region of the GAPDH promoter region and 346bp of pBR322. This procedure utilized digestion of 50μg of the pGAP-347 with 10 units each of BamHI and HindiII with the resulting fragment purified by prepara¬ tive gel electrophoresis in 1% agarose. A synthetic HindiII-XholI adapter molecule containing the codon for the initiator met and a Ncol site for analysis was synthesized and had the following sequence: AGCTTCCATGGA AGGTACCTCTAG. A third fragment was a XhoII-SacII fragment of l,187bp containing the gBl coding region. A fourth fragment containing the GAPDH termi¬ nator fragment (approximately 900bp) was isolated by Sall-BamHI digestion of a cloned fragment of the GAPDH gene with its 3' flanking region including the GAPDH SUBSTITUTE SHEET termination region, so that a portion of the coding region is included with the termination region. The two fragments can be ligated together by means of a SaclI-SalI adapter GGACAACTAG CGCCTGTTGATCAGC . These five fragments together with the cloning vector were ligated as follows: First, the XhoII-SacII fragment (2 picomoles) was ligated to 100 picomoles of each of the two adapters (HindiII-XholI, SacII-Sall) using T4 DNA ligase. The product was isolated by pre¬ parative gel electrophoresis in 1% agarose, providing a Hindlll-Sall fragment. The HindiII-Sail fragment (0.25 picomoles) was ligated in a single, step to the 1407bp BamHI-Hindi11 GAPDH promoter fragment (0.1 picomoles), the 900bp SalI-BamHI terminator (0.1 picomoles) and 0.02 picomoles of BamHI-digested, phosphatased pBR322 in the presence of T4 DNA ligase. » The above reaction product was used to trans- form E. coli HB101. Plasmids containing the cassette clones in pBR322 were isolated and the correct nucleo¬ tide sequence confirmed by DNA sequencing. This plasmid was then digested with BamHI and the BamHI cassette fragment containing the gBl segment and GAPDH regula- tory regions gel isolated and inserted into BamHI di¬ gested, phosphatased pCl/1. Plasmid pCl/1 is a deriva¬ tive of pJDB219 (Beggs, Nature (1978) 275:104) in which the region corresponding to bacterial plasmid pMB9 in pJDB219 is replaced by pBR322 in pCl/1. The pCl/1 plas- mid containing the 1187bp gBl insert and GAPDH promoter and terminator regions was designated pHS127A. This plasmid was then used to transform the yeast strain S_.. cerevisiae AB103.1 (α_, pep 4-3, leu 2-3, leu 2-112, ura 3-52, his 4-580) . Transformants were initially grown in 1.0ml of leu "* medium and then 50ml of YEPD inoculated with 0.4ml and grown further to an absorbence of 1-3 at 650nm (12hr). The yeast cells were pelleted by centri¬ fugation at 2krpm for lOmin at 4°C and resuspended in 50mM Tris-HCl, pH 8, 150mM NaCl, 0.2% Triton X-100, ImM EDTA and freshly added l.OmM phenylmethylsulfonyl fluo¬ ride and O.lμg/ml pepstatin. The cells were repelleted and then resuspended in a volume equal to the packed cell volume in the same buffer. An equal volume of acid-washed glass beads (diameter 0.45-0.5mm) was added and the yeast cells disrupted by vortexing at 4°C for lOmin total, using lmin intervals. The tubes were centrifuged for 15min at 14,000xg at 4°C and the supernatant isolated and ana¬ lyzed on 10% SDS polyacrylamide gel and blotted onto nitrocellulose paper for Western analysis (Burnett, Anal. Biochemistry (1981) 112:195) . A polyclonal anti¬ body (DAKO) to HSV-1 was employed as the primary anti¬ body. Expression of an HSV specific protein was ob¬ served at about 44kd, the size expected for the gB frag- ment. Isolation, cloning and characterization of the gB2 gene. The gene for glycoprotein gB2 was located by hybridization with specific DNA probes generated from the gBl coding region. As a first step, a restriction map was determined for the HindiII H fragment of HSV-2 strain 333 which spans map coordinates 0.28-0.39 as shown in Fig. 9. A random library of HSV-2 strain 333 sequences cloned into the lambda vector L-47.1 (Leonen and Brammar, Gene (1980) 10_:249) (obtained from Dr. James Casey, Louisiana State University) was generated by a partial Mbol digestion of the viral DNA and cloned into the BamHI site of the vector. The library was screened for plaque hybridization using a Kpnl-Ndel fragment of gBl as a probe. A positive lambda clone was picked and the lambda DNA prepared and digested with Sphl (Maniatis et al 4 , Molecular Cloning, Cold Spring Harbor Laboratory, 1982). A Southern blot analysis show that the gB2 information was contained within a 4.2kb fragment. The Sphl-di- gested lambda DNA was ligated to Sphl-digested pBR322 and the mixture used to transform E. coli HB101. The appropriate transformant was selected by restriction analysis and confirmed by Southern blot analysis. Three DNA pieces from the gBl gene were used as probes to Southern blots of restriction digests of the HindiII H fragment, a 0.93kb Pstl-Alul piece from the 5'-end of the gene, a 0.54kb Pstl-SalI piece from the central region and a 0.9kb Ncol-Ncol piece from the 3'-end. These fragments have been described previously. The hybridization pattern observed indicated that the gene spanned the two Xhol-Xhol fragments of 2.6kb and 2.75kb. The gB2 gene was cloned in a pBR322 derivative as two overlapping fragments. The 5'-end is contained within pHS203, a 2.6kb Xhol-Xhol clone, and the 3'-end within the adjacent 4.2kb Sphl-Sphl fragment, pH206, indicated on the above figure. A more detailed restriction map of the pHS203 Xhol subclone is shown in Fig. 10. The figure shows a restriction map of pHS203, a 2.6kb Xhol-Xhol fragment which contains the 5'-end of the gene encoding gB2. Line I shows a restriction map which includes the restriction sites for Bl, Ball.; Nr, Nrul; M, Smal; P, Pstl; S, Sail; Sp, Sphl; V, Pvul; X, Xhol; X , Xmalll. Those restriction sites marked by an asterisk are conserved between the DNA sequences of gBl and gB2. Line II shows three DNA fragments which were prepared by restriction digestion of pHS203 DNA and isolated by preparative gel electrophoresis and electroelution from *a 1% agarose gel. These pieces were used to probe Northern blots of mRNA from HSV-2-infected Vero cells to map precisely the location of the gB2 gene. Line III indicates the direction of transcription from right to E SHEET left. Line IV locates those DNA fragments of pHS203 which have been sequenced on the genetic map. The start of the DNA sequence, nucleotide 1, for gBl is also noted by the arrow. To verify the location of the gB2 gene, the three fragments indicated on Fig. 10 were prepared as probes to Northern blots of poly A mRNA isolated from HSV-2 infected Vero cells 12hr after infection. Two of the probes, the 850bp Xhol to Smal fragment and the adjacent 1150bp Smal to Nrul fragment both hybridized to an abundant mRNA of 3.0kb, the expected size and representation frequency expected for the gB2 message. The third probe, the 470bp Nrul-Xhol fragment did not hybridize to the same message. From a comparison of the HSV-1 and HSV-2 restriction maps, some of the restriction sites are conserved between the two species. To corroborate further the location of the gB2 gene and its homology with the gBl gene, DNA sequence analysis of selected regions of the -gB2 gene were determined. The sequence of the fragments is shown as follows in Table 3 including a comparison of the sequence of the 5'-end of gBl and gB2 for other than fragment DNA a. 40 Table 3 C AJ ' ' eBB ^ AAGGAGAACATCGCCCCGTACAAGTTCAAGGCCACCATGTACTACAAAGACGTCACCGTT TCGCAGGTGTG ****************** *** ***************************** *** *********** 1 AAGGAGAACATCGCCCC6ATCAAATTCAAGGCCACCATGTACTACAAAGACGTGACCT66GTCGCA6GT6T6. i 960 GTTCGGCCACCGCTACTCCCAGTTTATG6GGATCTTTGAGGACC6CGCCCCCGTCCCCTTCGAGGA6GTGAT ********************************* ** * * * * ** * ** * * * * *** ****************** 73 GTTCGGCCACCGCTACTCCCAGTTTATGGGGATATTCCAGGACCGCGCCCCCGTTCCCTTCGAGGAGGTGAT 1032 CGACAAGATC AACGCCAAGGGGGTCTGTCGGTCCACGGCCAAGTACGTGCGCAACAACCTGGAGACCACCG ******* ******* ****** ** * ***************** ** ****** ************ 145 CGACAAGCATTAACGCCAAGGGGG CTCTGCCTCCACGGCCAAGTACGTCCGGAACAACATGGAGACCACCG 1 04 C6TTTCACCGG6ACGACCACGAGACCGACATGGAGCTGAAACCGGCCAACGCCCGCGACCCGCACGAGCCGG ************************************* ** 4.4.4.** ** * *** ** ************ (A 217 CGTTTCACCGGGACGACCACGAGACCGACATGGAGCTCAAGCCGGCGAAGGT CGCCACGCGCACGAGCCGG c 00 1176 GGCTG6CACACCACCGACCTCAA6TACAACCCCTCGCGGGTGGAGGCGTTCCACCGGTACGG ACGACGGTA (0 ** **************************** ******************** ******** ******** H 2B9 GGGTGGCACACCACC6ACCTCAAGTACAACC TCGCGG6TGGAGGCGTTCCATCGGTACG6CACGACGGTC • H C <L> PI 1950 C *T*G*C*A*G*T*T*T*A*C*G*T*A*CA*A*C*C*A*C*A*T*A*C*A*G*C*G*C*C*A*TG*T*CA*A*C*G*A*TA*T*G*TT*G*G*G*C*CG**CGT*T6**CC*AT*C*G*C*G*T*G*G*T*G*C* ( 0 1 CTGCAGTTTACGTATAACCACAT A CAGCG CC ACGTGAACGACATGCTGGGGCGCATCGCCGTCGCGTGGTGC ac m 2022 G «A«G**CT*G*«C*AG*AATCACAA6CTGACCCT6TGGAAC6AGGCCCGCAAGCTGAACCCCAACGCCATCGCCTCGGCC U| 73 GAGCTGCAG X ki 2276 G*6*G*G*C*A*G*C*T*G*6*G*GG*A* G *A*A*C*A*A*C*G*A*G*C*T*G*C*G*GC*T*GA*C*G*C* G *CGAT G *C*GATCGAGCCGTGCACCGTGGGACACCG 1 6GG6CAGCTG6GCGAGAACAACGAGCT6CGCCTCACGCGACGCGC Table 3 A comparison of the homology between the DNA sequences b through f of HSV-2 gB2 and HSV-1 gBl. The top line of each comparison is the gBl sequence and the number given is the nucleotide base pair of that same sequence. The bottom line is the corresponding gB2 fragment, loop out regions or spaces have been inserted as required to display the maximum homology. Expression of gB2 in mammalian cells. Expression of HSV-2 glycoprotein gB has been achieved in COS cells (transient expression) and in CHO cells (stable cell line secreting gB2) transformed with pHS210 alone or cotransformed with pHS210 and a second plasmid containing dhfr. Plasmid pHS210 was constructed as follows. The entire gene was subcloned as a 3.8 b Nrul-BamHI fragment in pBR322 to generate pHS208. See Fig. 11. The Pstl site at the 5' end of the gene, lOObp to the right (downstream) of the Nrul site, was changed to a HindiII site by in vitro mutagenesis in M13. A HindiII to Pvu fragment of 1.9kb was then inserted into pSVl which was obtained by digestion of pSVl/dhfr with HindiII and Bglll. See Figs. 1 and 11. For this cloning step pHS208, was cut with PvuII and the end re¬ paired to blunt. The molecule was then cut with HindiII and the 1.9kb HindiII - (PvuII) fragment isolated by gel electrophoresis. Likewise pSVl/dhfr was cut with Bglll, repaired to blunt, cut with HindiII and the 4.85kb HindΙII-(BglII) vector fragment isolated by gel elec¬ trophoresis. These two fragments (1.9kb and 4.85kb) were ligated together to generate pHS210 - the expres¬ sion plasmid. Plasmid pHS210 was used directly to transform COS cells. Expression was detected by immunofluorescence using a gB specific monoclonal antibody, F3 A/B, and also using a commercially available polyclonal anti HSV-2 antibody (DAKO) as the primary antibody screen. Plates were coated with the monoclonal antibody. Sam¬ ples of cell culture medium were added to coated plates, then bound gB2 was detected with the rabbit anti HSV-2 polyclonal antibody (DAKO) followed by horseradish con¬ jugated goat antirabbit IgG. For CHO cell transformation plasmid pHS210 was used along with a second plasmid containing dhfr as a selective marker in a cotransfection protocol. Expres- sion was detected using an ELISA assay in which ELISA plates were coated with F3 A/B specific monoclonal anti¬ body. Glycoprotein D Materials and Methods All DNA manipulations were done according to standard procedures. See T. Maniatis et al., Molecular Cloning, Cold Spring Harbor Lab., (1982). Enzymes used in cloning were obtained either from New England Biolabs or Bethesda Research Laboratories and employed according to the supplier's directions. Yeast were transformed and grown using a variety of media including selective medium (yeast nitrogen base without leucine); YEPD me¬ dium, containing 1% (w/v) yeast extract, 2% (w/v) pep- tone and 2% (w/v) glucose, and others as appropriate and/or detailed below. In the case of plating medium contained 2% (w/v) agax and for transformation 3% top agar. Construction of yeast expression vectors containing synthetic DNA fragments coding for polypeptides A and B of the gD gene. " Nucleotide sequences designated gD-A and gD-B based on portions of the amino acid sequence for glyco¬ protein D of HSV-1 reported by Watson et al., Science (1982) 218:381-384, and employing preferred yeast codons, were devised. The gD-A sequence, which encodes amino acids 253-283 (corresponding to amino acids 258-288, as incorrectly numbered by Watson et al., supra.) of the mature protein, was as follows: TE SHEET Processing Site 4* ValProLeuAspLysArgLeuProProGluIeuSerGluThrProAsnAlaThrGln 5 ' -CCTTGGATAAAAGATTGCCACCAGAATTGTCTGAAACCCCAAACGCTACCCAA CATGGGAACCTATTTTCTAACGGTGGTCTTAACAGACTTTGGGGTTTGCGATGGGTT ProGluLeuAlaProGluAspProGluAspSerAlaLeuLeuGluAspProOP OC CCAGAATTGGCTCCAGAAGACCCAGAAGACTCTGCTTTGTTGGAAGACCCATGATAAG-3 ' GGTCTTAACCGAGGTCTTCTGGGTCTTCTGAGACGAAACAACCTTCTGGGTACTATTCAGCT The gD-B sequence, which encodes amino acids 8-23 ( corresponding to amino acids 13-28 , as incorrectly numbered by Watson et al . , supra. ) of the mature protein, was as follows : Processing Site 4- ValProLeuAspLysArgSerLeuLysMetAlaAspProAsnArgPheArgGlyLys 5 ' -CCTTGGATAAAAGATCTTTGAAGATGGCTGACCCAAACAGATTCAGAGGTAAG CATGGGAACCTATTTTCTAGAAACTTCTACCGACTGGGTTTGTCTAAGTCTCCATTC AspLeuProOP OC GACTTGCCATGATAAG-3 * CTGAACGGTACTATTCAGCT The sequences each include a Kpnl cohesive end at the 5 ' -end and a Sail cohesive end at the 3 ' -end. Coding for the mature secreted peptide begins after the LysArg processing site. The 5 ' -end of each sequence is a modification of the 3 ' -end of the naturally-occurring α ^ - factor secretory leader and processing signal sequence, where the modification consists of a deletion of three glu-ala pairs and a replacement of a leucine by a pro- line to create a Kpnl site in the nucleotide sequence. The 3 ' -end of each sequence includes two translational stop codons , OP and OC. SHEET Synthetic DNA fragments having the sequences just described were prepared by synthesizing overlapping ssDNA segments as described by Urdea et al. , Proc. Natl. Acad. Sci. USA (1984) 8_0:7461-7465 using the phosphorami- dite method of Beaucage and Caruthers, Tetrahedron Lett. (1981) 27:1859-1862, and annealing and ligating under the following conditions. The ssDNA fragments were joined as follows: 50 to 100 pmoles of each segment (except the two segments at the 5'-termini) were 5'-phosphorylated with 5.6 units of T4 polynucleotide kinase (New England Nuclear) in lOmM dithiothreitol (DTT), ImM ATP, lOmM MgCl 2 , lOOng/ml spermidine, 50mM Tris-HCl, pH 7.8 (total volume: 20μl) for 30 min at 37°C. Additional T4 kinase (5.6 units) was then added and the reaction continued for 30 min at 37°C. The fragments (except for the 5'- termini) were combined, diluted to 40μl with water fol¬ lowed by addition of 60μl of 1M sodium acetate, 12μl of 250mM EDTA, and 5μg of lmg/ml poly-dA. After heating for 5min at 65°C, the 5' terminal pieces were added, followed by 420μl of ethanol (100%). The solution was chilled for 20min at -80°C, centrifuged, and the pellet was washed twice with ethanol (100%) and dried. The pellet was redissolved in water (18μl), heated to 100°C for 2 minutes and then cooled slowly over 1.5 hours to 25°C in a water bath. The annealed fragment pool was ligated in a reaction mixture containing T4 DNA ligase (New England Biolabs, 1200 units) ImM ATP, lOmM DTT, lOmM MgCl 2 , lOOng/ml spermidine, and 50mM Tris-HCl, pH 7.8 (30μl). After 1 hour at 14°C, the reaction mixture was partially purified by preparative polyacrylamide gel (7%, native) electrophoresis. The DNA was removed from the appro¬ priate gel slice by electroelution and ethanol copre- cipitation with poly dA (5μg). After assembly, the synthetic gD-A and gD-B fragments were substituted into a Kpnl/Sall digested bacterial cloning plasmid pAB114c_EGF-24, which plasmid was prepared by cloning a mutagenized fragment of pYEGF-8 into pAB114 (see Fig. 3). The plasmids resulting from the insertion were designated pAB114αHS109 (gD-A) and pAB114αHS110 (gD-B). The preparation of pAB114 was as follows: Plasmid pABlOl was obtained from the screening of a random yeast genomic library cloned in YEp24 (Fasiolo _____ _____♦' J. Biol. Chem. (1981) 256:2324) using a synthetic 20-mer oligonucleotide probe (5'-TTAGTACATTGGTTGGCCGG-3' ) homologous to the published α ^ -factor coding region (Kurjan and Herskowitz, Abstracts (1981), Cold Springs Harbor meeting on the Molecular Biology of Yeasts, page 242). Plasmid AB11 was obtained by deleting the HindiII to Sail region of pBR322. An EcoRI fragment of pABlOl carrying the a-factor gene was then inserted into the unique EcoRI site in pABll to produce pAB112. Plasmid pAB112 was digested to comple¬ tion with HindiII, and then religated at low (4μg/ml) DNA concentration to produce plasmid pAB113 in which three 63bp Hindi11 fragments were deleted from the a- factor structural gene, leaving only a single copy of mature α_-factor coding region. A BamHI site was added to plasmid pABll by cleavage with EcoRI, filling in of the overhanging ends by the Klenow fragment of DNA poly¬ merase, ligation of BamHI linkers and religation to obtain a plasmid designated pAB12. Plasmid pAB113 was digested with EcoRI, the overhanging ends filled in, and ligated to BamHI linkers. After digestion with BamHI, the resulting 1500bp which carries the single copy of the α ^ -factor gene fragment was gel-purified and ligated to pAB12 which had been digested with BamHI and treated with alkaline phosphatase to produce pAB114, which contains a 1500bp BamHI fragment carrying the α_-factor gene. The preparation of pYEGF-8 was as follows: A synthetic sequence for human epidermal growth factor (EGF) was prepared and ligated to pAB112 (described above) which had been previously completely digested with Hindi11 and Sail to produce pAB201. The Hindi11 site lies within the 3'-end of the c^-factor gene, and the EGF sequence was inserted using appropriate linkers. The resulting plasmid was designated pAB201. Plasmid pAB201 (5μg) was digested to comple¬ tion with EcoRI and the resulting fragments were filled in with DNA polymerase I Klenow fragment and ligated to an excess of BamHI linkers. The resulting 1.75kbp frag¬ ment was isolated by preparative gel electrophoresis, and approximately lOOng of this fragment was ligated to lOng of yeast plasmid pCl/1 (described below) which had been previously digested to completion with restriction enzyme BamHI and treated with alkaline phosphatase. The ligation mixture of the 1.75 kbp fragment carrying the partial a-factor gene fused to the EGF gene and pCl/1 was used to transform E. coli HB101 cells, and transformants were selected based on ampicillin resis- tance. DNA from one ampicillin resistant clone (desig¬ nated pYEGF-8) was used to transform yeast AB103 (geno¬ type: MATα, pep 4-3, leu 2-3, leu 2-112, ura 3-52, his 4-580, cir°) cells, and transformants selected based on their leu phenotype. Plasmid pCl/1 is a derivative of pJDB219 (Beggs, Nature (1978) 275:104) where the region derived from bacterial plasmid pMB9 has been replaced by pBR322. The pCl/1 plasmid carries genes for both ampicillin resistance and leucine prototrophy. Plasmid pAB114αEGF-24 was generated by an in vitro mutagenesis procedure which deleted the sequences coding for the glu-ala processing region in the ^-factor leader. Plasmid pAB114αEGF-24 was obtained as follows: a Pstl-SalI fragment of pYEGF-8 containing the α_-factor leader hEGF fusion was cloned in phage M13 and isolated in single-stranded form. A synthetic 36-mer oligonucleo- tide primer (5 « -GGGGTACCTTTGGATAAAAGAAACTCCGACTCCGAA-3 f ) SHEET was used as a primer for the synthesis of the second strand using the Klenow fragment of DNA polymerase I. After fill-in and ligation at 14°C for 18 hours, the mixture was treated with S-, nuclease and used to trans- feet E. coli JM101 cells. Phage containing DNA sequences in which the glu-ala region was removed were located using 32P-labelled pri.mer as a probe. DNA from posi.ti.ve plaques was isolated, digested with Pstl and Sail, and the resulting fragment inserted into pAB114 (described above) which has been previously digested to completion with Sail, partially with Pstl and treated with alkaline phosphatase. The resulting plasmid was designated pABH4αEGF-24. Referring again to Fig. 3, the BamHI-BamHI fragment of pAB114 HS109 or pAB114 HS110 (1588 base- pairs for gD-A and 1546 base pairs for gD-B) was excised and ligated into the unique BamHI site of pCl/1. The resulting expression vectors were designated pYHS109 for gD-A and pYHSHO for gD-B. Expression of gD-A and gD-B polypeptides. Plasmids pYHS109 and pYHSllO were both used to transform yeast strain AB103.1 (α_, pep 4-3, leu 2-3, leu 2-112, ura 3-52, his 4-580, cir°) to leu prototrophy following the procedure of Hinnen et al., Proc. Natl. Acad. Sci. USA (1978) 75.:1929-1933. The transformants were grown in 1 L cultures at 30°C in buffered leucine- deficient media to saturation, corresponding to an absorb- ance of 5 at 650nm. Yeast cell cultures were maintained at saturation for an additional 12 to 24 hrs with shak- ing at 30°C. The cultures were then harvested, the intact yeast cells pelleted by centrifugation at 3000 RPM, and the resulting supernatant media filtered through a 0.22μ Millipore filter. This fraction was then passed through a C18 reverse phase column, constructed from 8 Seppak units purchased from Waters. The bound material was eluted with 30 ml of 80% (v/v) acetonitrile, 0.1% (v/v) trifluoroacetic acid in water, evaporated to dryness with a Buchii RotoVap and redissolved in 1.6ml of distilled water. This material was separated on a HPLC C18 column monitored at 210nm. The peak correspond- ing to each respective peptide was collected and its identity confirmed by antigenicity. Each peptide reacted specifically in an ELISA assay using rabbit polyclonal antisera which had been raised against a chemically synthesized gD-B peptide or partial gD-A peptide (resi- dues 256 through 271 of sequence shown in page 9) pur¬ chased from Vega Biochemicals. Expression levels, as determined by spectrophotometric measurements of HPLC purified peptides, were on the order of 7.6mg of gD-A per liter of yeast culture (OD 65Q =5) and 0.6mg of gD-B per liter of yeast culture (0D 65Q =5). These results demonstrate the feasibility of expressing a relatively short portion or fragment of a protein and its secretion from yeast cells using an -a-factor expression vector. Construction of yeast vectors for high level intra- , cellular expression using fragments of the naturally- occurring gD gene. Nucleotide fragments from the naturally- occurring gD gene expressing gP of HSV-1 (gP-1) were also expressed intracellularly in yeast under control of the GAPPH promoter and terminator. A library of EcoRI fragments of HSV-1, strain Patton, cloned into the EcoRI site of pBR322, was made by Dr. Richard Hyman, Hershey Medical Center, Hershey, Pennsylvania. The gP is entirely contained within a 2.9kb Sacl fragment with- in the EcoRI fragment of one clone (clone H) isolated from the HSV-1 library. Clone H was obtained from Pr. Hyman, the 2.9kb fragment was purified by gel electro¬ phoresis and was used for the construction of several expression vectors which differ in the size of the gP fragment cloned and/or the synthetic linkers used in the 5 1 or 3* ends of the gP fragments. Fig. 4 illus- trates the protein coding region (boxed region) and the fragments used for the construction of yeast expression vectors pYHSllδ, pYHS116, pYHS117, pYHS118 and pYHS119. A description of the construction of each plasmid follows. Construction of pYHS115. Plasmid pYHS115 contains the gD gene in a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expres¬ sion cassette cloned into the BamHI site of pCl/1 (de¬ scribed hereinabove). The GAPDH expression cassette was constructed as follows. Three fragments were'prepared (as described in detail below): (a) A BamHI-HindiII fragment (1407bp) con¬ taining 346bp of pBR322 and 1061bp of the GAPDH promoter; (b) A HindiII-SalI fragment (1430bp) con¬ taining the gD gene, and (c) A Sall-BamHI fragment (900bp) containing the GAPDH terminator. These fragments were ligated together and the mixture was digested with BamHI. The 3.7kb resulting cassette was isolated by gel electrophoresis and ligated to BamHI cut, alkaline phosphatase-treated pCl/1 (Fig. 3). Fragment (a) was prepared by completely digest- ing pGAP347 (described below) with BamHI followed by partial digestion with Hindlll. The resulting 1407 bp fragment containing 346bp of pBR322 and 1061bp of the GAPDH promoter was isolated by gel electrophoresis. Construction of pGAP347 was as follows (see copending U.S. application Serial No. 468,589, filed February 22, 1983): PolyA+ RNA was isolated from S_. cerevisiae yeast strain A364A. Double-stranded cDNA was synthe¬ sized using AMV reverse transcriptase and E. coli DNA polymerase I. Poly-dC-tails were added to the double- SUBSTITUTE SHEET stranded cDNA molecule using deoxynucleotide terminal transferase. Poly-dC-tailed cDNA was annealed to poly- dG-tailed pBR322 and used to transform E. coli HB101. 1000 transformants were screened by colony hybridiza- tion to labeled PolyA÷ RNA, and a subset further exa¬ mined by restriction endonuclease mapping, and DNA se¬ quencing. Three clones containing GAPDH sequences were isolated from the pool. One clone (pcGAP-9) contained an insert of about 1200 base pairs and was used for further work. A yeast gene library was prepared by inserting fragments obtained after partial digestion of total yeast DNA with restriction endonuclease Sau3A in lambda phage Charon 28, according to Blattner, et al. , Science (1977) 196:161-169. Several fragments containing yeast GAPDH coding sequences were isolated by screening the phage library with labeled DNA from pcGAP-9. The yeast GAPDH gene of one of these clones was subcloned in pBR322 as a 2.lkb HindiII fragment (pGAP-1). The GAPDH pro- moter region was isolated from these clones. A Hhal- Hindlll fragment of about 350bp containing the 3' por¬ tion of the promoter was obtained by: a) digestion of pGAP-1 with Hinfl to generate an approximately 500bp segment which includes the 3' part of the promoter and a region encoding the N-terminal amino acids of GAPDH; b) resection with Bal31 to yield a 400bp fragment lack¬ ing the GAPDH coding region (3'-terminus one base up¬ stream from the ATG initiator codon); c) addition of HindiII linkers; and d) cleavage with Hhal. A second HindiII-Hhal fragment of about 700bp containing the 5' portion of the promoter was isolated from pGAP-1, li¬ gated to the 350bp Hhal-Hindi11.fragment and treated with Hindlll. The resulting 1061bp Hindi11 fragment was isolated by gel electrophoresis and cloned in HindiII digested, alkaline phosphatase treated pBR322 to produce pGAP347. Fragment (b) was obtained as follows. Clone H, isolated from the HSV-1 Patton library was digested with Sacl. A 2.9kb Sacl fragment was purified by gel electrophoresis and subsequently digested with HindiII and Nrul. The 143Obp HindiII-Nrul fragment containing the gD gene (Fig. 3) was purified by gel electrophoresis, ligated to Nrul-Sail adaptors of the following sequence: 5'-TGATAAG-3' ACTATTCAGCT and digested with Sail. Fragment (c) was obtained as follows. A 900bp fragment containing the GAPDH terminator was obtained by BamHI and Sail digestion of pUH28 (described under "Construction of pYHS117") and purification by gel elec- trophoresis. Construction of pYHS116 pYHS116 contains a gD gene fragment which has a 600bp deletion at the 5' end of the coding region that comprises most of the signal sequence coding region. To construct pYHS116, two fragments were obtained: (a) A BamHI-Hindlll fragment (1407bp) con¬ taining 346bp of pBR322 and 1061bp of the GAPDH promoter. This fragment was obtained as described under "Construction of pYHS115. u (b) A Ncol-BamHI fragment (2150bp) contain¬ ing the partial gD gene followed by the GAPDH terminator. This fragment was obtained by BamHI/NcoI digestion of pYHS115 (described previously) and puri¬ fication by gel electrophoresis. A HindiII-Ncol chemically synthesized adaptor of the following sequence metval 5'-AGCTTAACATGGTC-3' ATTGTACCAGGTAC t *. 5 HindiII Ncol was ligated to the fragment. This adaptor provides for the first two codons- (met and val) fused in the correct reading frame to the partial gD. 10 Fragments (a) and (b) were ligated together and subsequently digested with BamHI. The resulting 3.5kb cassette was isolated by gel electrophoresis and ligated to BamHI cut, alkaline phosphatase treated pCl/1. 15 Construction of pYHS117 Plasmid pYHS117 contains the same partial gD gene clone in pYHS116, fused in reading frame to ' 7 extra codons at the 5'-end, which code for the first 7 amino acids of the GAPDH structural gene. To construct pYHS117 20 two fragments were obtained. (a) An Ncol-SalI digested vector (6.8kb) comprising pBR322 sequences, the GAPDH promoter fused to the first 7 codons of the structural gene and the GAPDH termi- 25 nator. This vector was prepared by Ncol digestion of pUH28 (described below), followed by a partial digestion with _ * _. Sail and purification by gel electropho¬ resis. 30 (b) An Ncol-Sail fragment (1430bp) contain¬ ing a partial gD gene. This fragment was obtained by Ncol-Sail digestion of pYHS115 (described previously in Section II.1.) and purification by gel electro- 35 phoresis. These two fragments were ligated together to yield a pBR322 derived vector which contains a partial gD gene fused in reading frame to the 7 first codons of GAPDH gene, flanked by the GAPDH promoter in its 5' end and by the GAPDH terminator in its 3' end. The gD ex¬ pression cassette was obtained by digesting this plasmid with BamHI and purifying a 3.4kb fragment by gel electrophoresis. This fragment was ligated to BamHI digested, alkaline phosphatase treated pCl/1 to produce pYHS117. Plasmid pUH28 contains the coding and 3' non- coding regions of the hepatitis B surface antigen (HBsAg) gene fused in incorrect reading frame to the first 7 codons of the GAPDH structural gene. This fusion is flanked in its 5' end by the GAPDH promoter and in its 3' end by part of the GAPDH coding region followed by the GAPDH terminator. This plasmid was constructed so as to have an ' Ncol site at the 3' end of the first 7 codons of the GAPDH gene with the following sequence: met 5'-AAACAAAATGGTTAGAGTTGCTAATTCC-3' TTTGTTTACCAATCTCAACGATTAAGGGTAC 3'GAPDH 5'GAPDH Ncol site promoter coding region When this Ncol end is ligated to the partial gD fragment (b, described above) the correct reading frame for the gD protein is regenerated. The Sail site used in the preparation of fragment a (described above) is at the 5' region of the GAPDH terminator. Therefore, a dele¬ tion of the sAg coding plus non-coding regions and GAPDH coding region was obtained by digesting pUH28 with Ncol and partially with Sail. The construction of pUH28 involves cloning of a fragment that contains the HBsAg coding and 607bp of 3' non-coding region prepared from pHBS5-3 Hae2-1 (de¬ scribed below) into the GAPDH containing vector pGAP, SUBSTITUTE SHEET (described below). To prepare the fragment, pHBS5-3 Hae2-1 was linearized by Pstl digestion, partially di¬ gested with Ncol and a Pstl-Ncol fragment of 1.9kb containing pBR322 sequences, HBsAg coding and 3' se- 5 quences was purified by gel electrophoresis. This fragment was subsequently digested with EcoRI and a 1.2kb Ncol-EcoRI fragment containing the HBsAg coding and 3' non-coding regions was purified by gel electro¬ phoresis. Plasmid pGAPI was linearized with Xbal and 10 treated with Bal31 to remove approximately lOObp. The plasmid was subsequently digested with Ncol and a vector fragment of about 9kb was purified by gel electrophore¬ sis. The Ncol ends of the vector and the 1.2kb Ncol- EcoRI fragment encoding HBsAg were ligated. The re- 15 cessed end was filled in with Klenow and the resulting blunt end was ligated to the blunt end of the vector obtained by Bal31 digestion to produce pUH28. pHBS5-3 Hae2-1 is a plasmid that contains the HBsAg coding region and 607bp of 3' flanking sequences. 20. This plasmid is a derivative of pHBS5-3 which contains the same insert but only 128bp of 3' untranslated re¬ gion instead of 607bp. Plasmid pHBS5-3 has been pre¬ viously described in copending U.S. application, serial no. 609,540, filed May 11, 1984, (pp. 13-14). pHBS5-3 25 Hae2-1 was constructed as follows. The HBV genome (3.2Kb) was excised from pHB-3200 (Valenzuela et al., Nature (1979) 280:815-819) by restriction digestion with EcoRI. The 3.2Kb fragment was purified by gel electrophoresis and was recircularized by ligation of 30 the EcoRI sticky ends. This closed HBV genome was digested with Haell, which cuts in the 3' non-coding region. Recessed ends were filled in with Klenow and HindiII linkers were ligated. The DNA was cut with HindiII and subsequently with Xbal, which has a single 35 site in the HBS coding region. A 1.2kb Xbal-HindiII fragment containing 586 base pairs of the coding sequence of HBV and 607 base pairs of the 3' non-coding region was isolated by gel electrophoresis. This fragment was cloned into pHBS5-3 previously cut with Xbal and HindiII and treated with alkaline phosphatase, to yield pHBS5-3 Hae2-1. pGAP-2 is a pBR322 derived vector which con¬ tains a BamHI insert that has the GAPDH coding sequence, 5' and 3' flanking regions. There are two Xbal sites in this plasmid: one in the coding region and one in the 3' flanking sequences. pGAP-2' is a derivative of pGAP-2 in which the Xbal site present in the 3' flanking region has been eliminated. For this purpose, 50μg of pGAP-2 were partially digested with Xbal, treated with Bal31 to remove 25 base pairs per end, and ligated. The plasmids were used to transform E. coli HB101 and the transformants were selected for loss of the Xbal site in the 3' flanking region. Construction of pYHS118 This vector contains a partial gD gene with deletions in two regions: a 600bp deletion in the 5'-end coding region which comprises most of the signal sequence coding region and a 1300bp deletion in the 3'-end coding region which includes most of the anchor sequence coding region. It also contains 7 extra codons from the GAPDH gene coding region fused in reading frame at the 5' end of the gD gene, similar to pYHS117. Plasmid pYHSllδ was constructed as follows. pYHS115 was digested with Ncol and Sail, the resulting 143Obp fragment containing the partial gD was purified by gel electrophoresis and submitted to digestion with Narl (Fig. 4). The two resulting fragments (fragment a: 873bp containing 5' end and fragment b: 411bp containing 3' end) were inde¬ pendently isolated by gel electrophoresis. Fragment b was subsequently digested with Sau96A to yield three fragments which were separated by gel electrophoresis. The 87bp Nar-Sau96A fragment was recovered from the gel UTE SHEET and was ligated to Sau96I-SalI synthetic adaptors of the following sequence: gly leu ile ala STOP 5'-GGC CTG ATC GCG TAG-3' G ACT AGC GCATCAGCT t t Sau96A Sail The NarI-(Sau96A)SalI fragment (102bp) was digested with Sail, purified by gel electrophoresis and ligated with fragment a (previously described). The resulting Ncol-SalI fragment (975bp) was ligated to Ncol-SalI digested and gel purified pUH28 as described under "Construction of pYHS117. ιr The resulting pBR322 derived vector was digested with BamHI and a 3.lkb fragment containing the gD expression cassette was purified by gel electrophoresis. This cassette was ligated to BamHI digested, alkaline phosphatase treated pCl/1 to produce pYHSllβ. Construction of pYHS119 This vector contains a partial gD gene with deletions in two regions: a 600bp deletion in the 5' end coding region which comprises most of the signal sequence coding region and a 2400bp deletion in the 3' end coding region which includes all the anchor sequence coding region and about 700bp upstream of the anchor sequence. It also contains 7 extra codons from the GAPDH gene coding region fused in reading frame at the 5' end of the gD gene, as pYHS117 and pYHS118. Plasmid pYHS119 was constructed as follows. pYHS115 was digested with Ncol and Sail, the resulting 143Obp fragment containing the partial gD was purified by gel electrophoresis and subsequently digested with Narl. The 873bp Ncol-Narl fragment was isolated by gel electrophoresis. A synthetic adaptor of the following sequence: 5'-CGCCGCAAATCTAC-3' GGCGTTTAGATCAGCT t t Narl Sail which provides complementary nucleotides to the Narl 5' overhang, 3 codons in reading frame, a stop codon and a 5* overhang of Sail, was ligated to the 873bp Ncol-Narl fragment then digested with Sail. The resulting Ncol- Sall fragment was ligated to pUH28 which had been pre- viously completely digested with Ncol and partially digested with Sail and purified by gel electrophoresis as described under "Construction of pYHS117." The re¬ sulting pBR322 derived vector was digested with BamHI and a 2.2kb fragment containing the gD expression cas- sette was purified by gel electrophoresis. This cas¬ sette was ligated to BamHI digested, alkaline phospha¬ tase treated pCl/1 to produce pYHS119. Synthesis of gD from vectors containing partial or complete gP gene. Plasmids pYHSllδ, 116, 117, 118 and 119 were used to transform yeast strain AB103.1 ((Ϊ, pep 4-3, leu 2-3, leu 2-113, ura 3-52, his 4-580, cir°) following the procedure of Hinnen et al., supra. The transfor¬ mants were grown to an °D 650 =3 at 30° in YEPP media. The cultures were then harvested by pelleting the yeast cells at 3000 RPM. Cells were spheroplasted with zymol- yase and subsequently os otically lysed in a hypotonic solution. Membranes were spun down in an eppendorf centrifuge, and the pellet was solubilized in 0.1% SPS with protease inhibitors for 16 hours at 4°C. The sus¬ pension was centrifuged and total protein, as well as gD specific protein, was determined in both soluble and insoluble fractions. Expression of the gD gene in each of the above described constructions was detected by Western Blot hybridization (Towbin et al. , Proc. Natl. Acad. Sci. USA (1979) 76:4350). For this purpose pro- tein samples were submitted to SDS-polyacrylamide gel electrophoresis (Laemmli, Nature (1970) 227:680) and electroblotted onto nitrocellulose filters (Towbin, et al., supra. ) . The filter was preincubated with goat serum and subsequently treated with a rabbit polyclonal antibody raised against HSV-1 (Dako). The filter was then incubated with a second goat anti-rabbit antibody conjugated with horseradish peroxidase (Boehringer- Mannheim) and finally it was incubated with horseradish peroxide color development reagent (Bio-Rad) and washed. The results indicate that immunoreactive material is being synthesized in yeast AB103.1 strain transformed with the gD expression vectors, with the exception of transformants containing pYHS115. In all other cases, gD protein corresponds to 0.1 to 0.5% of total yeast cell protein. Vaccine Trials Mice Experiments Experiment 1 Outbred female Swiss Webster mice (Simonsen) were immunized on day 1 with a 1.1 mixture of recombinant vaccine preparation and complete Freund's adjuvant. One half the dose was administered subcutaneously, the other half intraperitoneally. The mice received either 20μg recombinant gD protein or 5μg recombinant gB pro¬ tein. Mice were boosted on day 20 with the same dose and vaccine preparations, but incomplete Freund's adju¬ vant was used to make the emulsion. They were bled by cardiac puncture on day 28. Total lectin affinity puri- fied Patton strain HSV glycoproteins served as a positive vaccine control, and a recombinant Feline leukemia enve¬ lope B protein was used as a negative control. A second boost was given on day 41 and animals were bled again on day 53. Sera from the mouse bleeds were collected and assayed for antibody levels by ELISA and plaque reduction neutralization assay. The results of this experiment are summarized in Table 4 below. TABLE - EXPERIMENT 1 HUMORAL IMMUNITΪ IN MICE * Animal Immunogen Doee ELISA Tlter* Neutralization Tlter BLEED II 1 1 recombinant gD 20 μg 1:284 < 1:20 2 recombinant gD 20 μg 1:77 < 1:20 3 recombinant gD 20 μg 1:142 < 1:20 4 recombinant gB 5 μg 1:41750 5 recombinant gB 5 μg 1:24547 1:640 6 env B 20 μg < 1:10 < 1:20 7 total herpes glycoproteins 20 μg 1:175 1:125 BLEED ill 1 recombinant gD 20 μg 1:250 2 recombinant gD 20 μg 1:50 3 recombinant gD 20 μg 1:81 A recombinant gB 5 μg 1:17507 5 recombinant gB 5 μg 1:24155 6 env B 20 g < 1:10 7 total HSV glycopro iteins 20 μg 1:1468 a ELISA with 20 μg/ml total HSV-1 (Patton) glycoproteins as antigen, 50X endpoint. b Plaque reduction neutralization assay with complement, HSV-1 (Mclntyre), 50X endpoint. Experiment 2 The in vivo response of mice to the vaccine candidates was also examined by challenging immunized animals with a lethal dose of virus. Female Swiss Webster mice were immunized with the vaccine candidates. The first injections were done using 20μg recombinant gD or 5μg recombinant gB mixed in an equal volume of complete Freund's adjuvant. One half the dose was given intraperitoneally, the other half subcutaneously on day 1. Mice were boosted 2 and 4 weeks later in the same manner with incomplete Freund's adjuvant in the emulsion. Control animals received 20μg of lectin purified total HSV glycoproteins previously described or 23μg of a control yeast plus CHO cell extract. Mice were bled one week after the final boost by cardiac puncture. Sera were collected and assayed for antibody titers by ELISA. Animals were challenged fifteen days later with Q 3.25 x 10 pfu of HSV-1 (Patton) (2 *****-D 5Q!S ) gi en intra¬ peritoneally. They " were monitored for a 14 day time period for the appearance of clinical signs or morbidity. Mice surviving the virus challenge were observed for ten additional days at which time they were bled and the sera examined by ELISA. The results of this experi¬ ment are summarized in Table 5 below. TABLE 5; Experiment 2 Protection of Mice Against Virus Challenge Group Animal Immunogen Dose ELISA Titer t % Survival tt ELISA Titer * A 1:98 B 1:146 (A C recombinant gD 20μg n.d ** 40 (2/5) 1:862 C D 1:355 1:1514 03 E 1:106 (A -I A 1928 • H C B 1097 1:2660 H C recombinant gB 5μg 2660 80 (4/5) 1:1539 m D 1641 1:9641 CM E 13737 1:7573 en x A 1:2339 1:1928 π B total HSV 1:172 1:965 C glycoproteins 20μg 1:2660 100 (4/4) 1:5488 D 1:2883 1:3026 A <1:25 1:734 B 1:85 C control 23μg 1:51 20 (1/5) D cell extracts <1:25 E <1:25 t ELISA with lOμg/ml total HSV-1 (Patton) glycoproteins as antigen, 50% endpoint. tt Percent of mice surviving 14 days after challenge. (Number of surviving mice over total number.) ** Not done. No blood was obtained from this mouse for assay. * Sera tested from mice surviving virus challenge. Guinea Pig Experiments Experiment 1 Eighty-five weanling Hartley guinea pigs were divided into 10 groups as described in Table 6 below. The initial immunization contained 10-100μg of glycopro¬ tein in complete Freund's adjuvant in a volume of 100- 200μl injected into the hindlimb footpads, followed four weeks later by the same vaccine given intramuscularly to each hindlimb. Four weeks after the second immunization the animals were intravaginally inoculated with the HSV-2 MS strain. The animals were evaluated daily for 14 days to determine the severity of primary infection. The severity of the primary infection was determined by clinical observation of the lesions. The lesions were scored according to the following manifestation: 0 No clinical manifestations of infection 1 Redness, swelling 2 , Few small vesicles 3 Several large vesicles 4 Several large ulcers, maceration The results of this experiment are summarized in Table 6 below. The scores represent group averages. TABLE 6 SEVERITY OF PRIMARY INFECTION IN GUINEA PIGS CHALLENGED WITH HSV-2 Group I Immunogen Score' Range Number of Animals Control, yeast plus CHO 3.7 * 0.1 3-4 10 cell extracts plus CFA 10.μg recombinant gD 1.3 ± 0.3 0-3 plus CFA 100 μg recombinant gD 0.2 ± 0.2 0-1 C plus CFA 00 CO 20 μg recombinant gB 0.2 t 0.1 0-2 -_ plus CFA c -4 20 μg recombinant gB plus 0.7 ± 0.2 0-2 in 10 μg recombinant gD plus CFA to 50 μg Total HSV-1 glycoproteins 0.0 N/A X plus CFA m 7 50 μg Total HSV-1 glycoproteins 0.4 ± 0.1 0-1 7 8 50 μg Total HSV-2 glycoproteins 0.0 N/A θ plus CFA 50 μg Total HSV-2 glycoproteins 0.4 ± 0.2 0-1.5 B 10 Control, no treatmen 3 ± 0.3 0-4 16 a Seven days post challenge ^ ~ " 66 ' According to the present invention, novel vaccines are provided effective against Herpes Simplex Virus Types 1 and 2. These vaccines employ recombinant gB and gD or related polypeptides either separately or together. Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the appended claims. The following E. coli HB101 strains were deposited at the A.T.C.C, where the plasmid indicates the plasmid employed to transform the strain: pHS203; pHS112; pHS114; pHS127A and pHS206 were deposited on April 4, 1984, .and assigned Accession Nos. 39649-39653, respectively; pYHS109 and pYHSllδ were deposited on July 11, 1984, and given Accession Nos. 39762 and 39763 respectively. SHEET

Claims: WHAT I_l CLAIMED £S: 1. A vaccine comprising an effective amount to produce an immune response in a mammalian host of at least one of HSV glycoprotein B, immunogenically active fragment of HSV glycoprotein B, HSV glycoprotein D, or immunogenically active fragment of HSV glycoprotein D, prepared by expression of DNA constructs in a eukaryotic host, wherein the host for said glycoprotein D when used alone is yeast. 2. The vaccine of Claim 1, wherein said fragments are about 1500 to 5000 daltons molecular weight. 3. The vaccine of Claim 1, wherein said eukaryotic host is COS cells. 4. The vaccine of Claim 1 wherein said eukaryotic host is CHO cells. 5. The vaccine of Claim 1 wherein said eukaryotic host is yeast. 6. In a method for preparing vaccines against Herpes Simplex Virus, the improvement comprising: preparing at least one of HSV glycoprotein B, immunogenically active fragment of HSV glycoprotein B, HSV glycoprotein D, or immunogenically active fragment of HSV glycoprotein D, by expressing DNA constructs in a eukaryotic host, wherein the host for said glycoprotein D when used alone is yeast. 7. The method according to Claim 6, wherein said fragments are about 1500 to 5000 daltons molecular weight. SHEET 8. The method according to Claim 6, wherein said eukaryotic host is COS cells. 9. The method according to Claim 6, wherein said eukaryotic host is CHO cells. 10. The method according to Claim 6, wherein said eukaryotic host is yeast.

Inventors: BURKE RAE LYN, PACHL CAROL, URDEA MICKEY S, VALENZUELA PABLO D T, BURKE, RAE, LYN, PACHL, CAROL, URDEA, MICKEY, S., VALENZUELA, PABLO, D., T.
Applicants: CHIRON CORP, CHIRON CORPORATION
Application year: 1985
Main classification: A61K39
IPC codes: A61K39, C07K14, C12N15