CARBOXY TERMINAL IL-6 MUTEINS

Abstract: This invention relates to a Carboxy Terminal IL-6 Mutein with enhanced biological activity. The invention comprises a mutein of IL-6 having increased activity wherein the mutein has an amino acid substitution at, or corresponding to, amino acid location 171 or 175 of IL-6 having the wild-type sequence.

Description: Background of the Invention Carboxv Terminal IL-6 Muteins The present invention is directed to a mutein of Interleukin 6, its production by recombinant DNA technology, and its theraputic use. Interleukin-6 (IL-6) is a multifunctional cytokine that is produced by a variety of cells such as B-cells, T-cells, monocytes, fibroblasts and endothelial cells. IL-6 exhibits several activities relating to the proliferation and/or differentiation of hematopoietic progenitor cells. These activities result from IL-6 acting alone or in combination with other cytokines such as IL-3 and IL-4. Some specific biological effects of IL-6 include terminal differentiation of B-cells, proliferation and differentiation of T-cells, regulation of the acute phase response, growth regulation of epithelial cells, the differentiation of megakaryocytes, and thrombopoiesis. In accordance with these activities and effects, the target cells fo IL-6 include B-cells, T-cells, myeloma cells, megakaryocytes, monocytes, early stem cells and hepatocytes. Though IL-6 is a multifunctional cytokine, the various biological effects it exerts are believed to be initiated by the stepwise interaction of IL-6 with two distinct receptor subunits on a cell. IL-6 first forms a complex with an 80 kD receptor subunit. This complex binds to a non-ligand subunit, which is a membrane glycoprotein designated gpl30. The binding of the IL-6- 80kD receptor complex to gpl30 results in signal transduction. The amino acid sequence of IL-6 has been described in the literature as containing 185 amino acids starting with alanine as residue 1.; see, for example, Figure 2A of Brakenhoff et al., J. Immunol . 139, 4116-4121 (1987) and Figure 1 of Clark et al., PCT application WO 88/00206. These references also contain the cDNA sequence that corresponds to native IL-6 mRNA. The carboxy terminus of IL-6 has been found to be the receptor binding region. (See Leebeek, F.W.G., et al., "Identification of a Receptor Binding Site in the Carboxyl Terminus of Human Interleukin-6", Journal of Biological Chemistry in press) Analysis of the structure of the carboxy terminal 5 region of several cytokines, including IL-6, has shown the bindin region to be highly conserved. Lokker, N., et al., EMBO J. , 10, (8) 2125-2131 (1991). See page 2130, top of col. 1.; BAZAN, Immunology Today 11. 350-354 (1990). According to Lokker et al., "[Substitutions in the ... C-terminal proximal regions of these 10 molecules abolished their activity." New techniques in molecular biology, such as recombinant DNA and monoclonal antibodies, make it possible to study the relationships between the structure and function of proteins. 15 These techniques further enable the production of protein analogs with superior properties. The analogs may differ from native proteins by deletion, substitution, or addition of amino acids to the native sequence. Since the DNA and amino acid sequence of IL 6 is known, these techniques can be used to study and improve the 20 various properties of IL-6. For example, the deletion of amino acids may give important information about the function of a protein. Thus, Brakenhoff et al. have reported that the biological activity of IL-6 is not 25 affected by deletion of up to 28 amino acid residues from the amino terminus (N-terminus) of mature, native IL-6. Brakenhoff, J.P.J., et al., J. Immunol . l, 1175-1182 (1989). Conversely, deletion of only a few amino acids from the 30 carboxy terminus (C-terminus) of IL-6 has a pronounced effect on biological activity. For example, Krϋttgen et al. found that a deletion of the last amino acid from the carboxy terminus of IL-6 resulted in a five-fold loss of biological activity. Furthermore IL-6 lacking three or four carboxy terminal amino acids was found 3.5 to be completely inactive. Krϋttgen, A., et al., FEBS Lett . 273, 95-98 (1990). Since these truncated forms of IL-6 were not tested for binding to the IL-6 receptor, it remains unclear whether the loss of activity observed was due to a loss of receptor binding or to defective signal transduction upon IL-6 receptor interaction. In any event, the importance of the presence of the C-terminal amino acid residues is consistent with the highly conserved nature of this region, see above. Additional information about the importance of the carboxy terminus of IL-6 for biological activity was obtained by Brakenhoff et al. These authors showed by epitope mapping that neutralizing monoclonal antibodies against IL-6 were directed to region of the carboxy terminus. Brakenhoff, J.P.J., et al., J. Immunol . 1 5, 561-568 (1990). Native proteins may be improved by substituting amino acids for one or more of the amino acids that occur naturally in a protein. Such substitutions may be introduced into a protein by expressing recombinant DNA having a nucleotide sequence modified so as to have a codon that represents the desired amino acid. Proteins expressed by such modified DNA are called muteins. The DNA may conveniently be modified using the technique of saturatio mutagenesis. Hutchinson, C.A., et al., Proc. Natl . Acad. Sci . , U. S.A. 8 , 710-714 (1986). In a typical example of a mutein, native cysteine residues are replaced by other amino acid residues. Substituting other residues for cysteine residues may make it easier to express proteins in bacteria. Snouwaert, J., et al., J. Immunol. 146, 585 591 (1991); See page 589, col. 1, last paragraph bridging col 2, through first full paragraph. Muteins of IL-6 with improved biological activity relative t native IL-6 are desirable. An IL-6 mutein with enhanced biological activity would permit a lower dosage of the mutein to be administered to patients. Therefore, the costs of treatment and manufacture would be decreased with the more active IL-6 mutein. In addition, a lower dosage of the more active IL-6 mutein may reduce or eliminate possible side effects of the medication. It is the principal objective of the present invention to produce IL-6 muteins that have amino acid substitutions such that an increase in biological activity is achieved. Other objectives are to produce DNA, vectors and plasmids that encode muteins of IL-6 with increased activity. Summary of the Invention These and other objectives, as will become apparent to those with skill in the art, have been met by providing a mutein of IL- having increased activity wherein the mutein has an amino acid substitution at, or corresponding to, amino acid location 171 or 175 of IL-6 having the wild-type sequence. Description of the Drawings Figure 1 shows the 185 nucleic and amino acid sequence of a full length wild-type IL-6 starting with alanine as residue 1. Th underlined codons represent the sites of mutagenesis which result in the amino acid substitutions of the present invention. See SEQ ID. NOS. 1-2. Figure 2 shows the 185 nucleic and amino acid sequence of a full length mutein of human IL-6 starting with alanine as residue 1. The underlined codon represents a mutation wherein the phenylalanine residue at position 171 of wild-type IL-6 is substituted by leucine. See Example 1. and SEQ. ID. NOS. 3-4. Figure 3 shows the 185 nucleic and amino acid sequence of a full length mutein of human IL-6 starting with alanine as residue 1. The underlined codon represents a mutation wherein the leucin residue at position 175 of wild-type IL-6 is substituted by methionine. See Example 1. and SEQ. ID. NOS. 5-6. Figure 4 shows the 185 nucleic and amino acid sequence of a full length mutein of human IL-6 starting with alanine as residue 1. The underlined codons represent mutations wherein the phenylalanine residue at position 171 of wild-type IL-6 is substituted by leucine and the leucine residue at position 175 of wild-type IL-6 is substituted with methionine. See Example 1. and SEQ. ID. NOS. 7-8. Figure 5 shows the cloning strategy for the construction of the p560 expression vector used to introduce the C-terminal amino acid substitutions of the present invention into IL-6. Figure 6 is a table showing the biological activity and receptor binding capacity of nineteen C-terminal IL-6 muteins wit single amino acid substitutions at positions 171 through 185 of the wild-type sequence. (See Examples 3 and 4) The bar graph results of the IL-6 muteins of the present invention are located third and seventh from the top of the table. (See SEQ. ID. NOS. 17-35) Detailed Description of the Invention Definitions; The present invention is directed to muteins of IL-6 that have enhanced biological activity compared to that of native IL-6. It has now been unexpectedly discovered that certain mutations in the highly conserved carboxy terminal region of IL-6 result in increased biological activity. The mutations are amino acid substitutions. In this specification, IL-6 refers to human IL-6, and includes proteins described in the literature as having the same name as IL-6. Such proteins include interferon-β-2 (IFN-β-2), B- cell stimulation factor-2 (BSF-2), B-cell hybridoma/plasmacytoma growth factor (HPGF or HGF), 26 kDa protein and hepatocyte stimulating factor (HSF) . The sequence of native human IL-6 has been discussed above in the Background Section of this specification. The words "amino acid" in this specification are understood to mean the approximately 21 naturally occurring α-amino acids or their analogs. The present invention also includes isolated nucleic acid molecules that encode any of the muteins of the invention described above. The nucleic acid molecule may be DNA or RNA. The term "recombinant gene" in this specification is understood to mean a nucleic acid sequence that has been intentionally manipulated into a form that does not occur naturally. The term "mutein" in this specification is understood to mea a protein that has been modified at specific amino acid locations in the protein. The modifications in the mutein of the present invention are amino acid substitutions in the carboxy terminal region of IL-6. The muteins of the present invention are preferably essentially pure. Essentially pure means that the mutein is at least 85%, preferably at least 95% and more preferably, at least 98% free from other proteins and purification reagents. The muteins of the present invention exhibit increased biological activity in mammals. The activity of the muteins whic is determined in comparison with wild-type IL-6 may be in vitro, in vivo or both. For example, the in vitro biological activity of the IL-6 muteins of the invention may be compared with native IL-6 in a fibrinogen induction assay using a human hepatoma cell line, HEP3B2 or in a hybridoma proliferation assay using an IL-6 dependent murine hybridoma cell line, 7TD1. van Snick, J. , et al. Proc. Natl . Acad. Sci . , U. S.A. 83 » 9679-9683 (1986). The biological activities of the muteins of the invention are expressed as a percentage of activity of native, wild-type, IL-6. The activity of native IL-6 has been defined at 100% for both assays. The biological activity of the muteins of the present invention is at least 25% greater than the activity of wild-type IL-6. (See Figure 6) Two IL-6 muteins, each with a single point mutation, have been found to exhibit increased biological activity. A mutein containing both point mutations is also within the scope of the present invention. An IL-6 mutein with Phenylalanine at position 171 of the native sequence (Phe 171 ) replaced by Leucine (Leu) has higher biological activity, such as in vitro activity on a human hepatom cell line, compared to wild-type IL-6. The increased activity of this mutein is associated with increased receptor binding capacity. An IL-6 mutein with Leucine at position 175 of the native sequence (Leu 175 ) replaced by Methionine (Met) has higher biological activity, such as in vitro activity on a human hepatom cell line, compared to wild-type IL-6. The increased activity of this mutein is associated with decreased receptor binding capacity. A third IL-6 mutein contains mutations at both positions 171 (Phe→Leu) and 175 (Leu→Met). The increased biological activity of the muteins of the invention may be associated with increased binding capacity or with decreased binding capacity. Binding capacity is measured in terms of the affinity of an IL-6 receptor for wild-type IL-6 or the IL-6 muteins of the invention. The affinity may be determine with a Scatchard analysis and quantitated as a dissociation constant, K d . (See Leebeek, F.W.G., et al., "Identification of a Receptor Binding Site in the Carboxyl Terminus of Human Interleukin-6" , Journal of Biological Chemistry, in press) The binding capacity of the muteins of the invention is expressed as a percentage of the binding capacity of wild-type IL-6. The percentage is calculated by dividing the dissociation constant of wild-type IL-6 by the dissociation constant of an IL-6 mutein. The muteins of the present invention may contain all 185 amino acid residues corresponding to full length wild-type IL-6, as shown in Figure 1. Alternatively, from 1 to 28 amino terminal (N-terminal) amino acid residues may be deleted. For example, copending commonly owned patent application USSN 07/724,698 discloses deletion of 22 N-terminal amino acids from native wild- type IL-6. An N-terminal deleted form of the muteins of the invention will be designated -naa IL-6 F-L 171 or -naa IL-6 L-M 175 . The letter n represents the number of missing amino acid residues from the amino terminus. The single letter amino acid code is used to represent the amino acid substitutions at the positions previously described. F-L 171 represents the substitution of Phenylalanine by Leucine at position 171. L-M 175 represents the substitution of Leucine by Methionine at position 175. Thus, a mutein with the F-L 171 substitution having the first 22 N-terminal amino acids truncated is designated -22aa IL-6 F-L 171 . Where the two amino acid substitutions occur in the same mutein of the invention, the truncated form will be designated -naa IL-6 F-L 171 /L-M 175 . Native IL-6 contains four cysteine residues, which occur at positions 45, 51, 74 and 84 of the mature, full length sequence. These positions are based on the definition in this specification that the mature, native, full length IL-6 contains 185 amino acids starting with alanine as residue 1. The cysteine residues that correspond to positions 45 and 51 of native IL-6 may be replaced by other amino acids without losing significant activity. The cysteine residues that correspond to position 74 and 84 of native IL-6 must be retained. (See copending commonly owned patent application USSN 07/724,698) In this specification, a mutein of IL-6 that contains cysteine residues at positions 74 and 84, but not at positions 45 and 51, is called IL-6 XX 45 ' 51 wherein X represents any naturally occurring α-amino acid or an amino acid analogue. Preferably, X represents a neutral amino acid. The preferred neutral amino acids include alanine, serine, threonine, proline and glycine. Some preferred amino acid pairs for replacing the cysteine residues are serine and alanine. The two amino acids that replace the cysteine residues at positions corresponding to 45 and 51 of native, mature IL-6 (XX) may be the same or different. Some examples of XX include SS, AA, GG, DR, RD, SA, AS, etc. An amino acid deleted form of the muteins of the present invention that also has the first two cysteines residues substituted will be designated -naa IL-6 XX, wherein X and n are as defined above. Thus, some truncated muteins lacking the N- terminal 22 amino acids are designated -22aa IL-6 XX 45,51 /F-L 171 ; - 22aa IL-6 XX 45 ' 51 /L-M 175 ; and -22aa IL-6 XX 45 < 51 /F-L 171 /L-M 175 . The alanine at position 1 and the alanine-proline at positions 1 and 2 of mature, full length IL-6 are sometimes cleaved during processing of the protein. Therefore, the muteins of the invention often comprise pure IL-6 muteins, pure -laa IL-6 muteins, pure -2aa IL-6 muteins, or a mixture of two or three of IL-6, -laa IL-6 and -2aa IL-6 muteins. The present invention also includes equivalent variants of the muteins described above and the nucleic acid molecules that encode such variants. Equivalent variants include proteins comprising additions, deletions and substitutions in the amino acid and nucleotide sequences of the muteins of the invention and the corresponding nucleic acid molecules. Variants are included in the invention as long as the resulting muteins and nucleic acid molecules continue to satisfy the structural and functional criteria described above, i.e., retain enhanced biological activity at least comparable to that of the IL-6 mutein of the present invention with Phenylalanine at position 171 substituted with Leucine or Leucine at position 175 substituted with Methionine. An amino acid or nucleotide sequence that is substantially the same as another sequence, but that differs from the other sequence by means of one or more substitutions, additions or deletions is considered to be an equivalent sequence. Except for the substitutions of amino acid residues, described herein, at positions corresponding to positions 171 and 175 of native, mature IL-6, preferably less than 25%, more preferably less than 10%, and most preferably less than 5% of the total number of amino acids or nucleotides in the muteins of the invention are substituted for or added to in the equivalent sequences. For example, it is known to substitute amino acids in a sequence with equivalent amino acids. Groups of amino acids considered normally to be equivalent are: (a) Ala(A) Ser(S) Thr(T) Pro(P) Gly(G); (b) Asn(N) Asp(D) Glu(E) Gln(Q); (c) His(H) Arg(R) Lys(K); (d) Met(M) Leu(L) Ile(I) Val(V); and (e) Phe(F) Tyr(Y) Trρ(W) . Additions to the full-length and truncated IL-6 muteins may be made internally or at the C-terminal or N-terminal ends by adding the corresponding nucleic acid sequences at the appropriat location of the nucleic acid molecules encoding an IL-6 mutein, and expressing the nucleic acid molecules. Examples of internal additions to the nucleic acid molecules include the introns present in genomic DNA. The introns are not expressed in a suitable eukaryotic host cell. Equivalents of the nucleic acid molecules encoding IL-6 muteins also include silent mutations at sites that do not alter the amino acid sequence expressed. Preferably, the silent mutation results in increased expression in a particular host. UTILITY The IL-6 muteins of the invention are useful in the in vitro and in vivo proliferation and differentiation of B cells, T cells, megakaryocytes, and multi-potential hematopoietic progenitor cells. In addition, the IL-6 muteins induce various acute phase proteins in liver cells. The stimulation of proliferation of megakaryocytes leads to the production of platelets. As a result of these biological activities, the IL-6 muteins are useful in immunotherapeutic and anti-inflammation compositions. The mutein may also be used for the treatment of patients suffering from thrombocytopenia and patients undergoing chemotherapy or bone marrow transfers. Preferably, the IL-6 muteins of the present invention are used at lower dosages than native IL-6, since the lower dosages achieve the same level of biological activity. Preparation of the Muteins The muteins of the present invention may be prepared by methods known in the art. Such methods include synthesizing the IL-6 muteins chemically from individual amino acids, mutating or synthesizing DNA encoding the IL-6 mutein and using the DNA to produce recombinant protein. Chemical Synthesis of the Muteins The muteins of the present invention and DNA encoding the muteins may also be chemically synthesized by methods known in th art. Suitable methods for synthesizing the muteins are described by Stuart and Young in "Solid Phase Peptide Synthesis," Second Edition, Pierce Chemical Company (1984). Suitable methods for synthesizing DNA are described by Caruthers in Science 230. 281- 285 (1985). Recombinant Protein The muteins may be prepared by providing DNA that encodes th muteins; amplifying the DNA or cloning the DNA in a suitable host expressing the DNA in a suitable host; and harvesting the muteins Providing DNA Chemical Synthesis from Nucleotides The DNA may be synthesized chemically from the four nucleotides in whole or in part by methods known in the art. Suc methods include those described by Caruthers in Science 230, 281- 285 (1985). DNA may also be synthesized by preparing overlapping double- stranded oligonucleotides, filling in the gaps, and ligating the ends together. The DNA may be cloned in a suitable host cell and expressed. The DNA and mutein may be recovered from the host cell. See, generally, Sambrook et al, "Molecular Cloning," Secon Edition, Cold Spring Harbor Laboratory Press (1987). Mutants by Site-Directed Mutagenesis Mutant DNA expressing the mutated proteins may be prepared from wild-type IL-6 DNA by site-directed mutagenesis; see, for example, Zoller and Smith, Nucl . Acids Res . JP_, 6487-6500 (1982); Methods in Enzvmoloav 100, 468-500 (1983); and DNA ______ 479-488 (1984). Wild-type IL-6 DNA may be obtained by the method described by Jambou, R.C. et al., Proc . Natl . Acad. Sci . , USA 85 9426-9430 (1988). Alternatively, wild-type IL-6 DNA may be commercially obtained from Beckman Instruments Incorporated, 2500 N. Harbor Blvd., Fullerton, CA 92634, catalog number 267406. The substitution of cysteine residues may be accomplished by methods described in USSN 07/724,698 and the corresponding PCT application. Amplifying DNA The mutant DNA obtained may be amplified by methods known in the art. One suitable method is the polymerase chain reaction (PCR) method described by Saiki et al. in Science 239. 487 (1988), Mullis et al in U.S. Patent 4,683,195 and by Sambrook, Fritsch and Maniatis (eds) in Molecular Cloning, A Laboratory Manual , Second Edition, Cold Spring Harbor Laboratory Press (1989). It is convenient to amplify the clones in the lambda-gtlO or lambda-gtll vectors using lambda-gtlO or lambda-gtll-specific oligomers as the ampli ers (available from Clontech, Palo Alto, California). Expressing DNA The DNA encoding the mutein of the invention may be replicated and used to express recombinant protein following insertion into a wide variety of host cells in a wide variety of cloning and expression vectors. The host may be prokaryotic or eukaryotic. Cloning vectors may comprise segments of chromosomal, non- chromosomal and synthetic DNA sequences. Some suitable prokaryotic cloning vectors include plasmids from E. coli , such as colEl, pCRl, pBR322, pMB9, pUC, pKSM, and RP4. Prokaryotic vectors also include derivatives of phage DNA such as Ml3 fd, and other filamentous single-stranded DNA phages. Vectors for expressing muteins in bacteria, especially E. coli , are also known. Such vectors include the pK233 (or any of the tac family of plasmids), T7, and lambda P L . Examples of vectors that express fusion muteins are PATH vectors described by Dieckmann and Tzagoloff in J. Biol . Chem. 260, 1513-1520 (1985). These vectors contain DNA sequences that encode anthranilate synthetase (TrpE) followed by a polylinker at the carboxy terminus. For example, PATH 23 is an ampicillin-resistance plasmid containing a gene that encodes the amino-terminal 337 amino acids of trpE (anthranilate synthase component I) adjacent to, and it reading frame at its 3' end with, a polylinker containing a Hin lll site. A general description of the trpE operon may be found in Miller and Reznikoff, eds., The Operon, Cold Spring Harbor Laboratory, pp. 263-302 (1978). Other sources of DNA that encode all or part of trpE and lacz are readily available. Such other sources may be found, for example, in Pouwels, et al., Cloning Vectors, A Laboratory Manual , Elsevier, 1985. Suitable trpE sequences may be isolated from plasmids having the following identifying codes in the Pouwels, et al. manual; I-A-ii-3 (pDF41 and 42), I-A-iv-23 (pRK352), I-B-ii-4 (pMBL24), I-B-ii-1 (ptrpED-5-1) , I-D-i-3 (pEP70-pEP75) , and I-D-i 4 (pEPl65 and pEPl68). Other expression vector systems are based on beta-galactosidase (pEX); maltose binding protein (pMAL); glutathione S-transferase (pGST) - see Gene _______ , 31 (1988) and Peptide Research 3_, 167 (1990). Vectors useful for cloning and expression in yeast are available. A suitable example is the 2μ circle plasmid. Suitable cloning/expression vectors for use in mammalian cells are also known. Such vectors include well-known derivative of SV-40, adenovirus, cytomegalovirus (CMV) retrovirus-derived DN sequences and vectors derived from combination of plasmids and phage DNA. Further eukaryotic expression vectors are known in the art (e.g., P.J. Southern and P. Berg, J. Mol . Appl . Genet . ____, 327-341 (1982); S. Subramani et al, Mol . Cell . Biol . 1_, 854-864 (1981); R.J. Kaufmann and P.A. Sharp, "Amplification And Expression Of Sequences Cotransfected with A Modular Dihydrofolate Reductase Complementary DNA Gene," J. Mol . Biol . 159, 601-621 (1982); R.J. Kaufmann and P.A. Sharp, Mol . Cell . Biol . 159, 601-664 (1982); S.I. Scahill et al, "Expression And Characterization Of The Product Of A Human Immune Interferon DNA Gene In Chinese Hamster Ovary Cells," Proc. Natl . Acad. Sci . , USA 8_0_, 4654-4659 (1983); G. Urlaub and L.A. Chasin, Proc. Natl . Acad. Sci . , USA _T7_, 4216-4220, (1980). The expression vectors useful in the present invention contain at least one expression control sequence that is operatively linked to the DNA sequence or fragment to be expressed. The control sequence is inserted in the vector in order to control and to regulate the expression of the cloned DNA sequence. Examples of useful expression control sequences are the lac system, the trp system, the tac system, the trc system, major operator and promoter regions of phage lambda, the control region of fd coat protein, the glycolytic promoters of yeast, e.g., the promoter for 3-phosphoglycerate kinase, the promoters of yeast acid phosphatase, e.g., Pho5, the promoters of the yeast alpha- mating factors, and promoters derived from polyoma, adenovirus, retrovirus, and simian virus, e.g., the early and late promoters or SV40, and other sequences known to control the expression of genes of prokaryotic or eukaryotic cells and their viruses or combinations thereof. Useful expression hosts include well-known prokaryotic and eukaryotic cells. Some suitable prokaryotic hosts include, for example, E. coli , such as E. coli SG-936, E. coli HB 101, E. coli W3110, E. coli X1776, E. coli X2282, E. coli DHI, and E. coli MRC1, Pseudomonas, Bacillus , such as Bacillus subtilis, and Streptomyces . Suitable eukaryotic cells include yeasts and other fungi, insect, animal cells, such as COS cells and CHO cells, human cells and plant cells in tissue culture. Overexpressing DNA The mutein of the invention may be overexpressed behind an inducible promoter ana purified by affinity chromatography using specific IL-6 antibodies. As another alternative, the overexpressed protein may be purified using a combination of ion- exchange, size-exclusion, and hydrophobic interaction chromatography using methods known in the art. These and other suitable methods are described by Marston, "The Purification of Eukaryotic Polypeptides Expressed in E. coli " in DNA Cloning, D. M. Glover, Ed., Volume III, IRL Press Ltd., England, 1987. Fusion Proteins The muteins of the invention may be expressed in the form of a fusion protein with an appropriate fusion partner. The fusion partner preferably facilitates purification and identification. Increased yields may be achieved when the fusion partner is expressed naturally in the host cell. Some useful fusion partners include beta-galactosidase (Gray, et al., Proc . Natl . Acad. Sci . , USA 21, 6598 (1982)); trpE (Itakura et al., Science 198. 1056 (1977)); protein A (Uhlen et al., Gene 23 369 (1983)); glutathione S-transferase (Johnson, Nature 338, 585 (1989)); Van Etten et al., Cell j>8_, 669 (1989)); and maltose binding protein (Guan et al., Gene .67, 21-30 (1987); Maina et al. , Gene 74, 36-373 (1988); Riggs, P., in Ausebel, F.M. et al (eds) Current Protocols in Molecular Biology, Greene Associates/Wiley Interscience, New York (1990)). Such fusion proteins may be purified by affinity chromatography using reagents that bind to the fusion partner. The reagent may be a specific ligand of the fusion partner or an antibody, preferably a monoclonal antibody. For example, fusion proteins containing beta-galactosidase may be purified by affinity chromatography using an anti-beta-galactosidase antibody column (Ullman, Gene. 29_, 27-31 (1984)). Similarly, fusion proteins containing maltose binding protein may be purified by affinity chromatography using a column containing cross-linked amylose; see Guan, European Patent Application 286,239. Preferably, the DNA that encodes the fusion protein is engineered so that the fusion protein contains a cleavable site between the mutein and the fusion partner. More preferably, the fusion protein is linked to the carboxy-terminal side of the mutein of the invention, though linkage at the amino-terminal side is also possible. Both chemical and enzymatic cleavable sites are known in the art. Suitable examples of sites that are cleavable enzymatically include sites that are specifically recognized and cleaved by collagenase (Keil et al., FEBS Letters .56., 292-296 (1975)); enterokinase (Hopp et al., Biotechnology _β_, 1204-1210 (1988)); factor Xa (Nagai et al., Methods Enzymol . 153. 461-481 t (1987)); and thrombin (Eaton et al., Biochemistry 25, 505 (1986)). Collagenase cleaves between proline and X in the sequence Pro-X- Gly-Pro wherein X is a neutral amino acid. Enterokinase cleaves after lysine in the sequence Asp-Asp-Asp-Asp-Lys. Factor Xa cleaves after arginine in the sequence Ile-Glu-Gly-Arg. Thrombin cleaves between arginine and glycine in the sequence Arg-Gly-Ser- Pro. Specific chemical cleavage agents are also known. For example, cyanogen bromide cleaves at methionine residues in proteins. In one embodiment, the IL-6 muteins of the present invention arr made by mutating the wild-type IL-6 gene to have the codons that represent the desired amino acid substitution. The gene is then expressed in a prokaryotic or eukaryotic system, purified, analysed for biological activity and administered therapeutically. Initially, a high level IL-6-β-galactosidase expression vector, p340, described by Jambou et al., Proc . Natl . Acad. Sci . , USA 85.9426-9430 (1988), is modified to contain a synthetic minicistron that further increases the levels of protein expression. (See Jambou et al., Proc. Natl . Acad. Sci . , USA 139 4116-4121 (1988)) The modified vector is denoted p478. (See Snouwaert, J.N., et al., J. Immunol . 146, 585-591 (1991)) The p478 vector is used for the production of wild-type IL-6 as a control and for alteration to produce the IL-6 muteins of the present invention. The p478 vector allows the production of larg quantities of IL-6 and IL-6 muteins in 10 ml cultures. As depicted in Figure 5, in order to more efficiently select for mutated IL-6 in subsequent cloning procedures, a phenotypic change is introduced into the p478 expression vector. The p478 vector is altered so that the β-galactosidase gene is out of fram with the initiating methionine of IL-6. This is done by replacin the nucleic acid segment that encodes C-terminal amino acids of IL-6 with a 29 bp fragment that encodes three termination codons and Kpnlϊl and Hindlll restriction sites. The replaced IL-6 nucleic acid segment is located between the Bglll and Pmll restriction sites of the vector. As a result, functional β- galactosidase is not produced by the expression system. When the expression system is exposed to a colorimetric β-galactosidase substrate, the reaction product is not formed. The absence of th colored reaction product imbues the vector with a white phenotype The vector is denoted p560. Expression systems containing the p560 vector are selected based on the white phenotype. Once an expression system that contains the p560 vector has been selected, complementary oligonucleotides containing mutated C-terminal IL-6 sequences are cloned into the vector. The mutate oligonucleotides serve to introduce amino acid substitutions into IL-6 corresponding to positions 171 and 175 of the wild-type. In order to produce a p560 expression vector with mutated IL 6 sequences, the 29 bp segment, originally inserted between the Bglll and Pmll restriction sites of the vector, is removed and replaced with oligonucleotides that contain sequences that encode the IL-6 C-terminal amino acid substitution(s) of the present invention. During the procedure, the β-galactosidase gene is placed back in frame with the initiating methionine of the IL-6 mutein. Vectors that have properly incorporated the oligonucleotides will produce a functional β-galactosidase enzyme The colorimetric reaction product produced by the functional β- galactosidase enzyme is used to distinguish transformed vectors containing IL-6 muteins from non-transformed vectors. After ligation of the particular oligonucleotides into the p560 expression vector, the system is induced to express the mutated IL-6-β-galactosidase fusion protein. The expression system is exposed to a colorimetric substrate, such as 5-Bromo-4- chloro-3-indolyl β-d-galactopyranoside (BCIG), that is acted upon by the β-galactosidase enzyme, producing a colored reaction product. The colored colonies are selected and screened for the correct oligonucleotide insert using the polymerase chain reaction (PCR) . Selected vectors are further analyzed by dideoxy sequencing. Following expression of the desired mutated IL-6-β- galactosidase fusion protein, the mutated IL-6 portion is enzymatically cleaved to release the IL-6 mutein of the present invention. Lastly, the IL-6 mutein is purified by standard techniques and assayed for biological activity and binding capacity. Purifying Proteins The muteins of the present invention are purified by methods known in the art. Such methods include affinity chromatography using specific antibodies. Alternatively, the muteins may be purified using a combination of ion-exchange, size-exclusion, hydrophobic interaction chromatography and gel filtration using methods known in the art. These and other suitable methods are described by Marston, "The Purification of Eukaryotic Proteins Expressed in E. coli" in DNA Cloning, D. M. Glover, Ed., Volume III, IRL Press Ltd., England, 1987. The muteins of the present invention are preferably essentially pure. For the purposes of this specification, essentially pure means that the muteins are free from all but trace amounts of other proteins as well as of materials used during the purification process. Materials used in the purification process include detergents, affinity binding agents and separation films. Detergents include sodium dodecyl sulfate and sarcosine. Affinity binding agents include agarose, avidin- agarose, streptavidin-agarose, biotin and biotinylated proteins. Separation films include nitrocellulose paper and nitrocellulose/cellulose acetate paper. A mutein is considered to be essentially pure if it is at least 85%, preferably at least 95%, and more preferably at least 98% free of such materials. Examples Example 1. Mutagenesis As described in the "Fusion Proteins" Section, supra, and as depicted in Figure 5, a phenotypic change is introduced into the wild-type IL-6 expression vector p478 in order to select for IL-6 muteins later in the mutein construction process. The p478 vecto is altered by replacing the Bglll-Pmll segment of the vector with a 29 bp oligonucleotide. The sequences of the 29 bp oligonucleotide (a) and its complement (J ) are as follows: a = 5' GAT CTT AAG TAG TAG GTA CCA AGC TTG AC b = 3' AA TTC ATC ATC CAT GGT TCG AAG TG (See SEQ. ID. NOS. 9-10) These oligonucleotides are made on a DNA synthesizer (Applie Biosystems 380A, Foster City, CA) and purified by reverse-phase high-performance liquid chromatography. Reagents are obtained from American Bionetics (Hayward, CA) . The altered p478 vector is denoted p560. In order to introduce mutated C-terminal IL-6 nucleic acid sequences into the p560 expression vector, a 129 bp nucleic acid fragment that contains the mutated sequences is produced and cloned into the p560 vector. The fragment is constructed by joining two complementary oligonucleotide pairs, c-f and d-e. Th oligonucleotide pair c-f is synthesized to have one or more point mutations in the sequence encoding the C-terminus of IL-6. A point mutation is made by the saturation mutagenesis method described by Hutchinson et al., Proc . Natl . Acad. Sci . , USA 83 710-714 (1986). Using the method, oligonucleotides c and f are mutagenized by using a mixture of phosphoramidites in the synthesis mixes during their synthesis. The synthesis mixture contains 96% of the four deoxynucleotides thymidine, adenine, guanine and cytosine and a 4% equimolar mixture of the four comparable phosphoramidites. By contaminating one phosphoramidit with a small amount of each of the other three phosphoramidites during synthesis of the oligonucleotide, an oligonucleotide is obtained that has one or more mutations in its sequence compared to the wild-type gene. The other oligonucleotide pair, d-e, is sythesized and purified by the following procedure. I. Automated Synthesis Procedures. The 2-cyanoethyl phosphoramidites are purchased from Applied Biosystems Inc. The procedure includes condensation of nucleosid phosphoramidites to 30 mg of a nucleoside-derivatized controlled pore glass (CPG) bead support (500 Angstrom pore diameter), using DNA synthesizer from Applied Biosystems Inc., Type 380B-02. The cycles includes detritylation with 2% trichloroacetic acid in dichloromethane; condensation using tetrazol as an activating proton donor; capping with acetic anhydride and dimethylaminopyridme; detritylation using 2% trichloroacetic aci in dichloromethane; and oxidation of the phosphite to the phosphate with 0.1 M I 2 /H 2 0/lutidine/tetrahydrofuran. Cycle time is approximately 30 minutes. Yields at each step are essentially quantitative and are determined by collection and spectroscopic examination of the dimethoxytrityl alcohol released during detritylation. II. Oligodeoxyribonucleotide Deprotection and Purification Procedures The solid support is removed from the column and exposed to 1 ml concentrated ammonium hydroxide at 60°C for 16 hours in a closed tube. Ammonia is removed and the residue is applied to a preparative 12% polyacrylamide gel using a Tris-borate buffer (pH 8) containing 7M urea. Electrophoresis is carried out at 20 volts/cm for 5 hours after which the band containing the product is identified by UV shadowing of a fluorescent plate. The band is excised and eluted with 1 ml double distilled water overnight at room temperature. This solution is filtered and the supernatant is extracted (3x 300 microliter) with n-butanol. The water phase is placed on a Sephadex G50 column (Pharmacia) (lx 10cm). The elution is monitored by UV absorbance at 260 nm and the appropriate fraction collected, quantitated by UV absorbance in a fixed volume and evaporated to dryness at room temperature in a vacuum centrifuge. III. 5'- Phosphorylation of d and e sequences In order to phosphorylate 5'-ends of the d and e new-phosphorylating reagent as described by T. Horn et al., Tetrahedron Letters , 27.: 4705-08 (1986) is used. Only the ends of the nucleotides that are to be joined together will be phosphorylated. The synthesis of d and e is described as in I. Automated Synthesis Procedure, but after the last cycle, the phosphorylating reagent 0 II DMT-0-CH 2 CH 2 -S-CH 2 CH 2 -0-P-N ( iPr ) 2 ( 0-CH 2 CH 2 CN ) 0 (Glen Corp. Inc.) (DMT is dimethoxytrityl group; iPr is isopropyl) is condensed to each of the sequences d and e using tetrazol as an activating proton donor, followed by capping with acetic anhydride and dimethylaminopyridine; detritylation using 2% trichloroacetic acid in dichloromethane; and oxidation of the phosphite to the phosphate with 0.1M I 2 /H 2 0/lutidine/tetrahydrofuran, Cycle time is approximately 30 minutes. The 5'-phosphorylated d and e are purified and quantitated by the procedure described in II above. The complete sequence of the four oligonucleotides is as follows: C= 5' GAT CTT TTA AGG AGT TCC TGC AGT CTA GCC TGA GAG CTC TTC GGC AAA TGT CAG ACT CTG TGC C d= 5' TGT TGG TCC TGT TGG TCC TGC TGG TGC TTT TGG CCC AAG AGG TCT CGC TGG CCC ACA AGG TCC AC e= 5' GTG GAC CTT GTG GGC CAG CGA GAC CTC TTG GGC CAA AAG CAC CAG CAG GAC CAA CAG GAC C f= 5' AAC AGG CAC AGA ATC TGA CAT TTG CCG AAG AGC TCT CAG GCT AGA CTG CAG GAA CTC CTT AAA A (See SEQ. ID. NOS. 11-14) The non-underlined part of oligonucleotides c and f as well as the complete oligonucleotides d and e are identical to the original segments in the wild-type IL-6 expression vector (p478). The underlined parts of the oligonucleotides represent the codons that, when mutated, encode a substituted C-terminal amino acid of an IL-6 mutein of the present invention. In particular, the TTT codon of oligonucleotide c codes for Phenylalanine at position 171 of the wild-type IL-6. When the TTT codon is mutated to TTG, TTA, CTT, CTC, CTA or CTG, Phenylalanine 171 is substituted with Leucine. Similarly, codon CTG of oligonucleotide c codes for Leucine at position 175 of wild-type IL-6. When codon CTG is mutated to ATG, Leucine 175 is substituted with Methionine. Following synthesis, the oligonucleotides are purified by HPLC. Once purified, complementary oligonucleotides c-f and d-e are annealed and kinased. The annealed pairs are then ligated to form a single 129 bp fragment with oligonucleotides c and d functioning as the coding strand. The complete sequence of the 129 bp fragment is as follows: c 5' GAT CTT TTA AGG AGT TCC TGC AGT CTA GCC TGA GAG CTC TTC GGC 3' AA AAT TCC TCA AGG ACG TCA GAT CGG ACT CTC GAG AAG CCG d AAA TGT CAG ACT CTG TGC CTG TTG GTC CTG TTG GTC CTG CTG GTG CTT TTT ACA GTC TGA GAC ACG GAC AAC CAG GAC AAC CAG GAC GAC CAC GGA TTG GCC CAA GAG GTC TCG CTG GCC CAC AAG CTG CAC 3' 129 AAC CGG GTT CTC CAG AGC GAC CGG GTG TTC CAG CTC 5' e (See SEQ. ID. NOS.15-16) The 129 bp fragment contains the last 46 bases of the IL-6 gene and part of the collagen linker of the fusion protein. The size of the fragment is confirmed by agarose gel electrophoresis and purified by electroelution. Following excision of the 29 bp fragment that replaced the Bgrlll-Pmll segment of the p478 vector, the 129 bp fragment is cloned into the p560 vector at the Bglll cleavage site. (See Figure 5) This reconstruction of the vector results in an expression vector with the complete IL-6-β-galactosidase fusion protein with a point mutation in the C-terminal region of IL-6 that encodes an amino acid substitution of the present invention. Once p560 vectors containing mutated IL-6 C-terminal sequences are constructed, XL-1 Blue cells (Stratagene, La Jolla, CA) are transformed with the vector according to standard procedures. Part of the transformation mixture is plated out on Luria-broth culture plates that are coated with ampicillin and tetracycline as selection markers; isopropyl-B-D- thiogalactopyranoside (IPTG) for induction of fusion protein synthesis; and 5-Bromo-4-chloro-3-indolyl β-d-galactopyranoside (BCIG) as a substrate for β-galactosidase to permit selection of colonies by their dark-blue color. Part of the transformation mixture is incubated in L-broth- ampicillin/tetracycline as an overnight culture. This first transformation results in mixed colonies because the complementary oligonucleotides c and f are likely to have different sequences due to the mutagenesis procedure. The colonies are washed off of the plates with 2 ml of SOB medium. The recipe for SOB medium is as follows: 1) Bacto tryptone (2%) 2) Bacto yeast extract (0.5%) 3) NaCl (10 mM) 4) KC1 (2.5 mM) 5) MgCl 2 (10 mM) 6) MgS0 4 p560 DNA is purified and used for a consecutive transformation of XL-1 Blue cells to obtain pure colonies. This retransformation is done after the DNA is digested with Hindlll. The Hindlll digestion results in a reduced background, because it only cleaves plasmid p560 without the 129 bp insert. The transformation mixture is plated out on L-broth- ampicillin/tetracycline plates coated with IPTG and BCIG. A total of 250 blue colonies are checked for having the 129 bp insert by the polymerase chain reaction (PCR) . Two oligonucleotides are used. One inside the IL-6 gene and one in the expression vector (collagen linker). PCR is carried out according to standard procedures. (Saiki et a:., in Science 239, 487 (1988), Mullis et al in U.S. Patent 4,683,195 and by Sambrook, Fritsch and Maniatis (eds) in Molecular Cloning, A Laboratory Manual , Second Edition, Cold Spring Harbor Laboratory Press (1989)) The plasmids that have the correct size insert are further analyzed by dideoxy sequencing. Example 2. Expression, purification and guantitation of recombinant IL-6 muteins Detailed description of the bacterial expression system used in the invention has previously been published. Snouwaert, J.N., et al., J. Immunol . 146, 585-591 (1991); Jambou, R.C., et al., Proc. Natl . Acad. Sci . , U. S.A. 139, 4116-4121 (1988); Snouwaert, J.N., et al., J. Biol . Chem. .266., 23097-23102 (1991). The expression vector containing the gene for the fusion protein with the desired IL-6 mutein is transformed into Escherichia coli JM101. Single ampicillin resistant colonies are picked to inoculate 10 ml broth cultures. At log phase growth of the bacteria, expression of the fusion protein is induced by addition of 100 μl of isopropyl-B-D-thiogalactopyranoside (IPTG) (25 mg/ml). β-galactosidase activity is measured and at maximum levels of activity, bacteria are pelleted by centrifugation and stored at -20°C until further use. Bacteria are resuspended in 1 ml 0.5X phosphate buffered saline (PBS) and lysed by repeated freezing and thawing after lysozyme treatment. To reduce viscosity, the lysate is sonicated and the fusion protein pelleted by centrifugation. The pellet is washed to remove soluble contaminants and the fusion protein is solubilized in 2% sodium lauroyl sarcosine. Insoluble contaminants are removed by centrifugation and the fusion protein is precipitated by two rounds of selective ammonium sulfate precipitation. The IL-6 mutein is cleaved from the β- galactosidase by collagenase treatment prior to quantitation or use in bioassays. Because of the high amounts of IL-6 mutein expressed in the induced bacteria, it is possible to quantitate the protein preparations by denaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions followed by Coomassie staining and scanning laser densito etry. Example 3. Bioassav of IL-6 Muteins The biological activity of wild-type IL-6 and IL-6 muteins can be measured by the following two assays. Both assays are carried out in duplicate serial dilutions of three or more independent preparations of each IL-6 mutein. The biological activities are determined from dose response curves prepared for each protein preparation. To minimize variation in these biological assays, a duplicate protein preparation of wild-type IL-6 is used in each 96-well tissue culture plate to calculate the activity of two (HEP3B2) or three (7TD1) IL-6 muteins on the same plate as a percentage of wild-type IL-6 activity. (See Figure 6) I. Hybridoma growth assay The hybridoma growth factor activity of wild-type IL-6 and IL-6 muteins is measured using an IL-6 dependent, mouse-mouse hybrid cell line (7TD1) as described by van Snick, J., et al., Proc. Natl . Acad. Sci . , U. S.A. 83, 9679-9683 (1986). 7TD1 cells are suspended at a density of 2 X 10 4 cell/ml in Iscove's DMEM medium containing 10% fetal bovine serum, L-arginine (0.55 mM), L- asparagine (0.24 mM) , L-glutamine (1.5 mM), β-mercaptoethanol (50 μM) , hypoxanthine (0.1 mM) , thymidine (16 uM), and penicillin/streptomycin. Cells are plated in 96-well tissue culture plates (100 μl/well). IL-6 controls and mutein samples to be tested are diluted into the same medium. Each dilution is tested by adding 100 μl/well to the plated cells. After 4 or 5 days, the number of cells is evaluated by colorimetric determination of the hexosaminidase levels. Optical density is read from plates at a wavelength of 405 nm (OD 405 ) on a V max ELISA plate reader (Molecular Devices Corp., Palo Alto, CA) . OD 405 is assumed to be directly proportional to the cell number and is plotted directly against the log of the IL-6 concentration. For the HEP3B2 assay, the OD 40 , is converted to fibrinogen concentration using the V max plate reader software before being plotted. For each assay, the roughly linear portion of each dose-response curve is fitted with a second order polynomial curve using a computer program. The IL-6 concentratio that gives half maximal proliferation in the 7TD1 assay is calculated for each IL-6 mutein, and this value is used to calculate hybridoma growth activity relative to the wild-type IL- 6. II. Hepatocyte Stimulation Assay Hepatocyte stimulation activity of wild-type IL-6 and IL-6 muteins is measured using a human hepatoma cell line HEP3B2. The cells are maintained in DMEM-H medium supplemented with 10% fetal bovine serum and penicillin/streptomycin. On the day before treatment, cells are trypsinized and plated on 96-well tissue culture plates at a density sufficient to give confluent monolayers after overnight growth. The next day, the IL-6 mutein to be tested are diluted in maintenance medium supplemented with 10" 6 dexamethasone. Each dilution is tested in duplicate by addin 100 μl/well to the plated cells. Conditioned medium is collected after 48 hours and assayed for fibrinogen production by a sandwic ELISA using a commercially available capture antibody (IgG fraction, goat anti-human fibrinogen; Cappel, Durham, N.C.) and a peroxidase-conjugated detection antibody (peroxidase conjugated IgG fraction, goat anti-human fibrinogen; Cappel, Durham, N.C). Color is developed using a peroxidase substrate (Kirkegaard & Perry, Gaithersburg, MD). The OD 405 is on a V ma>! ELISA plate reade (Molecular Devices Corp., Palo Alto, CA) . The activity of native IL-6 and IL-6 muteins in the assay is defined as the IL-6 concentration that causes a doubling of fibrinogen secretion. The activity of each IL-6 mutant is calculated by taking the mean and the standard error of the mean of the activities determined for the independent protein preparations. Example 4. Binding assay of IL-6 Muteins Binding competition assays are performed using human recombinant IL-6 derived from Escherichia coli (Genetics Institute, Cambridge, MA). IL-6 is radioiodinated using the Bolton-Hunter reagent (New England Nuclear, Wilmington, DE) as described by Faltynek, C.R., et al., J. Immunol . 136, 4134-4139 (1986). The specific activity of the radiolabelled IL-6 is 22 μC/μg. For the binding experiments, a human myeloma cell line U- 266 is used. The cells are grown in RPMI 1640 medium supplemented with 10% fetal bovine serum, 2mM L-glutamine and penicillin/streptomycin. This medium is also used for making the dilutions of the IL-6 muteins and as the binding medium. The fetal bovine serum batches are routinely tested for IL-6 activity and only batches that show negligible IL-6 activity are used for competition binding assays. Cells are harvested by low speed centrifugation, washed once in Ca ++ /Mg + free phosphate buffered saline and resuspended at a concentration of 10 7 cells/ml medium at 4°C. The IL-6 muteins are treated with collagenase and diluted immediately afterwards to the desired concentrations in binding medium. 125 l-IL-6 is diluted to a concentration of 16 ng/ml. Thereafter, 100 μl of cells, 50 μl of IL-6 mutein and 50 μl of 125 l-lL-6 are transferred in rapid succession using a 12-well multichannel pipet into round-bottom, polyvinyl 96-well plates (Dynatech, Chantilly, VA) to yield a final concentration of 10 6 cells/200 μl, 0.2 nM labelled IL-6 and varying concentrations of IL-6 mutein (1600 to 0.194 ng/200 μl). Binding is performed by sealing the plates with acetate plate sealers (ICN Biomedicals, Costa Mesa, CA) and end-over rotation for 3 hours at 4°C. Thereafter, cells are quickly pelleted by spinning the plates in a Beckman TJ-6 table-top centrifuge (Beckman Instruments, Fullerton CA) . The supernatants are aspirated using a 12 channel aspiration/washing device (Immuno Wash 12, Nunc, Denmark). The cell pellets are washed once with 200 μl of ice-cold Ca ++ /Mg + free Hank's balanced salt solution (HBSS), resuspended in 200 μl of HBSS, transferred to scintillation vials and counted in a gamma counter. Scatchard analysis and the competition binding experiments i performed by measuring the binding in the presence of a constant concentration of 125 I-IL-6 and varying concentrations of unlabelled IL-6 mutein. The results of the Scatchard and competition bindin assays are analyzed using a non-linear curve fitting program LIGAND. (Analytical Biostatistical Section, Division of Computer Research and Technology, National Institutes of Health, Bethesda, MD 20892) After the K d of wild-type IL-6 and the IL-6 mutein for the receptor are calculated, the receptor binding capacity of the IL-6 muteins are expressed as a percentage of receptor binding of wild-type IL-6. The percentage is calculated by dividing the K d - wild-type IL-6 by the K d -IL-6 mutein. An apparent IC 50 is calculated using the EBDA/LIGAND program. (See Figure 6) SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: Fowlkes, Dana M. (ii) TITLE OF INVENTION: Carboxy Terminal IL-6 Muteins (iii) NUMBER OF SEQUENCES: 35 (iv) CORRESPONDENCE ADDRESS: (A) ADDRESSEE: ImClone Systems Incorporated (B) STREET: 180 Varick Street (C) CITY: New York (D) STATE: New York (E) COUNTRY: U.S.A. J (F) ZIP: 11014 (v) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS-DOS (D) SOFTWARE: Patentln Release #1.0, Version #1.25 (vi) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: (B) FILING DATE: (C) CLASSIFICATION: (vii) PRIOR APPLICATION DATA: (A) APPLICATION NUMBER: US 07/918,181 (B) FILING DATE: 23-JUL-1992 (viii) ATTORNEY/AGENT INFORMATION: (A) NAME: Feit, Irving N. (B) REGISTRATION NUMBER: 28,601 (C) REFERENCE/DOCKET NUMBER: FOW-2-T (ix) TELECOMMUNICATION INFORMATION: (A) TELEPHONE: 212-645-1405 (B) TELEFAX: 212-645-2054 (2) INFORMATION FOR SEQ ID NO:l: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 564 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..558 (ix) FEATURE: (A) NAME/KEY: mat_peptide (E) LOCATION: 1..555 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:l: GCT CCG GTT CCG CCA GGA GAA GAT TCC AAA GAT GTA GCC GCC CCA CAC 48 Ala Pro Val Pro Pro Gly Glu Asp Ser Lys Asp Val Ala Ala Pro His 1 5 10 15 AGA CAG CCG CTC ACC TCT TCA GAA CGA ATC GAT AAA CAA ATT CGG TAC 96 Arg Gin Pro Leu Thr Ser Ser Glu Arg lie Asp Lys Gin lie Arg Tyr 20 25 30 ATC CTC GAC GGG ATA TCA GCG CTG AGA AAA GAG ACC TGT AAC AAG AGT 144 lie Leu Asp Gly lie Ser Ala Leu Arg Lys Glu Thr Cys Asn Lys Ser 35 40 45 AAC ATG TGT GAA AGC AGT AAA GAA GCA CTG GCA GAA AAC AAC CTG AAC 192 Asn Met Cys Glu Ser Ser Lys Glu Ala Leu Ala Glu Asn Asn Leu Asn 50 55 60 CTT CCG AAG ATG GCT GAA AAA GAT GGA TGT TTT CAA TCT GGA TTC AAT 240 Leu Pro Lys Met Ala Glu Lys Asp Gly Cys Phe Gin Ser Gly Phe Asn f 65 70 75 80 GAG GAA ACT TGT CTG GTG AAA ATC ATC ACA GGC CTT TTG GAA TTT GAG 288 Glu Glu Thr Cys Leu Val Lys lie lie Thr Gly Leu Leu Glu Phe Glu 85 90 95 GTA TAC CTA GAG TAC CTC CAG AAC AGA TTT GAG AGT AGT GAG GAA CAA 336 Val Tyr Leu Glu Tyr Leu Gin Asn Arg Phe Glu Ser Ser Glu Glu Gin 100 105 110 GCG AGA GCT GTC CAG ATG TCG ACC AAA GTC CTG ATC CAG TTT CTG CAG 384 Ala Arg Ala Val Gin Met Ser Thr Lys Val Leu lie Gin Phe Leu Gin 115 120 125 AAA AAG GCA AAA AAT CTA GAT GCA ATA ACC ACC CCG GAT CCA ACC ACA 432 Lys AAT GCG AGC CTG CTG ACG AAG CTG CAG GCA CAG AAC CAG TGG CTG CAG 480 Asn Ala Ser Leu Leu Thr Lys Leu Gin Ala Gin Asn Gin Trp Leu Gin 145 150 155 160 GAC ATG ACA ACT CAT CTC ATT CTG AGA TCT TTT AAA GAA TTC CTG CAG 528 Asp Met Thr Thr His Leu lie Leu Arg Ser Phe Lys Glu Phe Leu Gin 165 170 175 TCC TCC CTG CGT GCT CTG CGT CAG ATG TAATGATAG 564 Ser Ser Leu Arg Ala Leu Arg Gin Met 180 185 (2) INFORMATION FOR SEQ ID NO:2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 185 amino acids J (B) TYPE: amino acid 4>- (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2: Ala Pro Val Pro Pro Gly Glu Asp Ser Lys Asp Val Ala Ala Pro His 1 5 10 15 Arg Gin Pro Leu Thr Ser Ser Glu Arg He Asp Lys Gin He Arg Tyr 20 25 30 He Leu Asp Gly He Ser Ala Leu Arg Lys Glu Thr Cys Asn Lys Ser 35 40 45 Asn Met Cys Glu Ser Ser Lys Glu Ala Leu Ala Glu Asn Asn Leu Asn 50 55 60 Leu Pro Lys Met Ala Glu Lys Asp Gly Cys Phe Gin Ser Gly Phe Asn 65 70 75 80 Glu Glu Thr Cys Leu Val Lys He He Thr Gly Leu Leu Glu Phe Glu 85 90 95 Val Tyr Leu Glu Tyr Leu Gin Asn Arg Phe Glu Ser Ser Glu Glu Gin 100 105 110 Ala Arg Ala Val Gin Met Ser Thr Lys Val Leu He Gin Phe Leu Gin 115 120 125 Lys Lys Ala Lys Asn Leu Asp Ala He Thr Thr Pro Asp Pro Thr Thr 130 135 140 Asn Ala Ser Leu Leu Thr Lys Leu Gin Ala Gin Asn Gin Trp Leu Gin 145 150 155 160 Asp Met Thr Thr His Leu He Leu Arg Ser Phe Lys Glu Phe Leu Gin 165 170 175 4 Ser Ser Leu Arg Ala Leu Arg Gin Met t π 180 185 (2) INFORMATION FOR SEQ ID NO:3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 564 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (E) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA ( iii ) HYPOTHETICAL : NO ( iv ) ANTI-SENSE : NO (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..558 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3: GCT CCG GTT CCG CCA GGA GAA GAT TCC AAA GAT GTA GCC GCC CCA CAC 48 Ala Pro Val Pro Pro Gly Glu Asp Ser Lys Asp Val Ala Ala Pro His 1 5 10 15 AGA CAG CCG CTC ACC TCT TCA GAA CGA ATC GAT AAA CAA ATT CGG TAC 96 Arg Gin Pro Leu Thr Ser Ser Glu Arg He Asp Lys Gin He Arg Tyr 20 25 30 OI CO ATC CTC GAC GGG ATA TCA GCG CTG AGA AAA GAG ACC TGT AAC AAG AGT 144 He Leu Asp Gly He Ser Ala Leu Arg Lys Glu Thr Cys Asn Lys Ser 35 40 45 AAC ATG TGT GAA AGC AGT AAA GAA GCA CTG GCA GAA AAC AAC CTG AAC 192 Asn Met Cys Glu Ser Ser Lys Glu Ala Leu Ala Glu Asn Asn Leu Asn 50 55 60 CTT CCG AAG ATG GCT GAA AAA GAT GGA TGT TTT CAA TCT GGA TTC AAT 240 Leu Pro Lys Met Ala Glu Lys Asp Gly Cys Phe Gin Ser Gly Phe Asn 65 70 75 80 GAG GAA ACT TGT CTG GTG AAA ATC ATC ACA GGC CTT TTG GAA TTT GAG 288 Glu Glu Thr Cys Leu Val Lys He He Thr Gly Leu Leu Glu Phe Glu 85 90 95 GTA TAC CTA GAG TAC CTC CAG AAC AGA TTT GAG AGT AGT GAG GAA CAA 336 Val Tyr Leu Glu Tyr Leu Gin Asn Arg Phe Glu Ser Ser Glu Glu Gin 100 105 110 GCG AGA GCT GTC CAG ATG TCG ACC AAA GTC CTG ATC CAG TTT CTG CAG 384 Ala Arg Ala Val Gin Met Ser Thr Lys Val Leu He Gin Phe Leu Gin 115 120 125 AAA AAG GCA AAA AAT CTA GAT GCA ATA ACC ACC CCG GAT CCA ACC ACA 432 Lys Lys Ala Lys Asn Leu Asp Ala He Thr Thr Pro Asp Pro Thr Thr 130 135 140 AAT GCG AGC CTG CTG ACG AAG CTG CAG GCA CAG AAC CAG TGG CTG CAG 480 Asn Ala Ser Leu Leu Thr Lys Leu Gin Ala Gin Asn Gin Trp Leu Gin 145 150 155 160 GAC ATG ACA ACT CAT CTC ATT CTG AGA TCT TTG AAA GAA TTC CTG CAG 528 t Asp Met Thr Thr His Leu He Leu Arg Ser Leu Lys Glu Phe Leu Gin ^ 165 170 175 TCC TCC CTG CGT GCT CTG CGT CAG ATG TAATGATAG 565 Ser Ser Leu Arg Ala Leu Arg Gin Met 180 185 (2) INFORMATION FOR SEQ ID NO:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 185 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear " ■ (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4: Ala Pro Val Pro Pro Gly Glu Asp Ser Lys Asp Val Ala Ala Pro His 1 5 10 15 Arg Gin Pro Leu Thr Ser Ser Glu Arg He Asp Lys Gin He Arg Tyr 20 25 30 He Leu Asp Gly He Ser Ala Leu Arg Lys Glu Thr Cys Asn Lys Ser 35 40 45 Asn Met Cys Glu Ser Ser Lys Glu Ala Leu Ala Glu Asn Asn Leu Asn 50 55 60 Leu Pro Lys Met Ala Glu Lys Asp Gly Cys Phe Gin Ser Gly Phe Asn 65 70 75 80 Glu Glu Thr Cys Leu Val Lys He He Thr Gly Leu Leu Glu Phe Glu 00 85 90 95 Val Tyr Leu Glu Tyr Leu Gin Asn Arg Phe Glu Ser Ser Glu Glu Gin 100 105 110 Ala Arg Ala Val Gin Met Ser Thr Lys Val Leu He Gin Phe Leu Gin 115 120 125 Lys Lys Ala Lys Asn Leu Asp Ala He Thr Thr Pro Asp Pro Thr Thr 130 135 140 Asn Ala Ser Leu Leu Thr Lys Leu Gin Ala Gin Asn Gin Trp Leu Gin 145 150 155 160 Asp Met Thr Thr His Leu He Leu Arg Ser Leu Lys Glu Phe Leu Gin 165 170 175 Ser Ser Leu Arg Ala Leu Arg Gin Met 180 185 (2) INFORMATION FOR SEQ ID NO:5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 564 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: CDNA (iii) HYPOTHETICAL: NO OJ ( iv ) ANTI-SENSE : NO CO (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..558 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5: GCT CCG GTT CCG CCA GGA GAA GAT TCC AAA GAT GTA GCC GCC CCA CAC 48 Ala Pro Val Pro Pro Gly Glu Asp Ser Lys Asp Val Ala Ala Pro His 1 5 10 15 AGA CAG CCG CTC ACC TCT TCA GAA CGA ATC GAT AAA CAA ATT CGG TAC 96 Arg Gin Pro Leu Thr Ser Ser Glu Arg He Asp Lys Gin He Arg Tyr 20 25 30 ATC CTC GAC GGG ATA TCA GCG CTG AGA AAA GAG ACC TGT AAC AAG AGT 144 He Leu Asp Gly He Ser Ala Leu Arg Lys Glu Thr Cys Asn Lys Ser 35 40 45 AAC ATG TGT GAA AGC AGT AAA GAA GCA CTG GCA GAA AAC AAC CTG AAC 192 Asn Met Cys Glu Ser Ser Lys Glu Ala Leu Ala Glu Asn Asn Leu Asn 50 55 60 CTT CCG AAG ATG GCT GAA AAA GAT GGA TGT TTT CAA TCT GGA TTC AAT 240 Leu Pro Lys Met Ala Glu Lys Asp Gly Cys Phe Gin Ser Gly Phe Asn 65 70 75 80 GAG GAA ACT TGT CTG GTG AAA ATC ATC ACA GGC CTT TTG GAA TTT GAG 288 Glu Glu Thr Cys Leu Val Lys He He Thr Gly Leu Leu Glu Phe Glu 85 90 95 o GTA TAC CTA GAG TAC CTC CAG AAC AGA TTT GAG AGT AGT GAG GAA CAA 336 Val Tyr Leu Glu Tyr Leu Gin Asn Arg Phe Glu Ser Ser Glu Glu Gin 100 105 110 GCG AGA GCT GTC CAG ATG TCG ACC AAA GTC CTG ATC CAG TTT CTG CAG 384 Ala Arg Ala Val Gin Met Ser Thr Lys Val Leu He Gin Phe Leu Gin 115 120 125 AAA AAG GCA AAA AAT CTA GAT GCA ATA ACC ACC CCG GAT CCA ACC ACA 432 Lys Lys Ala Lys Asn Leu Asp Ala He Thr Thr Pro Asp Pro Thr Thr 130 135 140 AAT GCG AGC CTG CTG ACG AAG CTG CAG GCA CAG AAC CAG TGG CTG CAG 480 Asn Ala Ser Leu Leu Thr Lys Leu Gin Ala Gin Asn Gin Trp Leu Gin 145 150 155 160 GAC ATG ACA ACT CAT CTC ATT CTG AGA TCT TTT AAA GAA TTC ATG CAG 528 Asp Met Thr Thr His Leu He Leu Arg Ser Phe Lys Glu Phe Met Gin 165 170 175 TCC TCC CTG CGT GCT CTG CGT CAG ATG TAATGATAG 564 Ser Ser Leu Arg Ala Leu Arg Gin Met 180 185 (2) INFORMATION FOR SEQ ID NO:6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 185 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6: Ala Pro Val Pro Pro Gly Glu Asp Ser Lys Asp Val Ala Ala Pro His 1 5 10 15 Arg Gin Pro Leu Thr Ser Ser Glu Arg He Asp Lys Gin He Arg Tyr 20 25 30 He Leu Asp Gly He Ser Ala Leu Arg Lys Glu Thr Cys Asn Lys Ser 35 40 45 Asn Met Cys Glu Ser Ser Lys Glu Ala Leu Ala Glu Asn Asn Leu Asn 50 55 60 Leu Pro Lys Met Ala Glu Lys Asp Gly Cys Phe Gin Ser Gly Phe Asn 65 70 75 80 Glu Glu Thr Cys Leu Val Lys He He Thr Gly Leu Leu Glu Phe Glu 85 90 95 Val Tyr Leu Ala Arg Ala Val Gin Met Ser Thr Lys Val Leu He Gin Phe Leu Gin 115 120 125 Lys Lys Ala Lys Asn Leu Asp Ala He Thr Thr Pro Asp Pro Thr Thr 130 135 140 Asn Ala Ser Leu Leu Thr Lys Leu Gin Ala Gin Asn Gin Trp Leu Gin 145 150 155 160 Asp Met Thr Thr His Leu He Leu Arg Ser Phe Lys Glu Phe Met Gin 165 170 175 .fc- •^ Ser Ser Leu Arg Ala Leu Arg Gin Met 180 185 (2) INFORMATION FOR SEQ ID NO:7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 564 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO ( iv ) ANTI -SENSE : NO (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..558 (ix) FEATURE: (A) NAME/KEY: mat_peptide (B) LOCATION: 1..555 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7: GCT CCG GTT CCG CCA GGA GAA GAT TCC AAA GAT GTA GCC GCC CCA CAC 48 Ala Pro Val Pro Pro Gly Glu Asp Ser Lys Asp Val Ala Ala Pro His 1 5 10 15 AGA CAG CCG CTC ACC TCT TCA GAA CGA ATC GAT AAA CAA ATT CGG TAC 96 Arg Gin Pro Leu Thr Ser Ser Glu Arg He Asp Lys Gin He Arg Tyr 20 25 30 ATC CTC GAC GGG ATA TCA GCG CTG AGA AAA GAG ACC TGT AAC AAG AGT 144 s. He Leu Asp Gly He Ser Ala Leu Arg Lys Glu Thr Cys Asn Lys Ser OI 35 40 45 AAC ATG TGT GAA AGC AGT AAA GAA GCA CTG GCA GAA AAC AAC CTG AAC 192 Asn Met Cys Glu Ser Ser Lys Glu Ala Leu Ala Glu Asn Asn Leu Asn 50 55 60 CTT CCG AAG ATG GCT GAA AAA GAT GGA TGT TTT CAA TCT GGA TTC AAT 240 Leu Pro Lys Met Ala Glu Lys Asp Gly Cys Phe Gin Ser Gly Phe Asn 65 70 75 80 GAG GAA ACT TGT CTG GTG AAA ATC ATC ACA GGC CTT TTG GAA TTT GAG 288 Glu Glu Thr Cys L GTA TAC CTA GAG TAC CTC CAG AAC AGA TTT GAG AGT AGT GAG GAA CAA 336 Val Tyr Leu Glu Tyr Leu Gin Asn Arg Phe Glu Ser Ser Glu Glu Gin 100 105 110 GCG AGA GCT GTC CAG ATG TCG ACC AAA GTC CTG ATC CAG TTT CTG CAG 384 Ala Arg Ala Val Gin Met Ser Thr Lys Val Leu He Gin Phe Leu Gin 115 120 125 AAA AAG GCA AAA AAT CTA GAT GCA ATA ACC ACC CCG GAT CCA ACC ACA 432 Lys Lys Ala Lys Asn Leu Asp Ala He Thr Thr Pro Asp Pro Thr Thr 130 135 140 AAT GCG AGC CTG CTG ACG AAG CTG CAG GCA CAG AAC CAG TGG CTG CAG 480 Asn Ala Ser Leu Leu Thr Lys Leu Gin Ala Gin Asn Gin Trp Leu Gin 145 150 155 160 GAC ATG ACA ACT CAT CTC ATT CTG AGA TCT TTG AAA GAA TTC ATG CAG 528 Asp Met Thr Thr His Leu He Leu Arg Ser Leu Lys Glu Phe Met Gin 165 . 170 175 TCC TCC CTG CGT GCT CTG CGT CAG ATG TAATGATAG 564 4^ Ser Ser Leu Arg Ala Leu Arg Gin Met 180 185 (2) INFORMATION FOR SEQ ID NO:8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 185 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8: (2) INFORMATION FOR SEQ ID NO:9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 29 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9: GATCCTAAGT AGTAGGTACC AAGCTTGAC 29 O T (2) INFORMATION FOR SEQ ID NO: 10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 25 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10: GTGAAGCTTG GTACCTACTA CTTAA 25 (2) INFORMATION FOR SEQ ID NO:11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 64 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: CDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO >* « 3 (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11: GATCTTTTAA GGAGTTCCTG CAGTCTAGCC TGAGAGCTCT TCGGCAAATG TCAGACTCTG 60 TGCC 64 (2) INFORMATION FOR SEQ ID NO: 12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 65 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear ( ii ) MOLECULE TYPE : CDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12: TGTTGGTCCT GTTGGTCCTG CTGGTGCTTT TGGCCCAAGA GGTCTCGCTG GCCCACAAGG 60 TCCAC 65 (2) INFORMATION FOR SEQ ID NO:13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 61 base pairs -CN. (B) TYPE: nucleic acid 00 (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13: GTGGACCTTG TGGGCCAGCG AGACCTCTTG GGCCAAAAGC ACCAGCAGGA CCAACAGGAC 60 C 61 (2) INFORMATION FOR SEQ ID NO:14: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 64 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: CDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 14: AACAGGCACA GAATCTGACA TTTGCCGAAG AGCTCTCAGG CTAGACTGCA GGAACTCCTT 60 AAAA 64 (2) INFORMATION FOR SEQ ID NO:15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 129 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: CDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15: GATCTTTTAA GGAGTTCCTG CAGTCTAGCC TGAGAGCTCT TCGGCAAATG TCAGACTCTG 60 TGCCTGAAGG TCCTGTTGGT CCTGCTGGTG CTTTTGGCCC AAGAGGTCTC GCTGGCCCAC 120 AAGCTGCAC 129 (2) INFORMATION FOR SEQ ID NO: 16: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 125 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA Cj -, (iϋ) HYPOTHETICAL: NO O (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 16: CTCGACCTTG TGGGCCAGCG AGACCTCTTG GGCCAAAGGC ACCAGCAGGA CCAACAGGAC 60 CAACAGGCAC AGAGTCTGAC ATTTGCCGAA GAGCTCTCAG GCTAGACTGC AGGAACTCCT 120 TAAAA 125 (2) INFORMATION FOR SEQ ID NO:17: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal ς ! (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17: Phe Lys Asp Phe Leu Gin Ser Ser Leu Arg Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:18: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (E) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 18: Cys Lys Glu Phe Leu Gin Ser Ser Leu Arg Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear n (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 19: Leu Lys Glu Phe Leu Gin Ser Ser Leu Arg Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:20: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 am o acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20: Phe Gin Glu Phe Leu Gin Ser Ser Leu Arg Ala Leu Arg Gin Met en 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:21: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21: Phe Lys Asp Phe Leu Gin Ser Ser Leu Arg Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:22: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO n (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:22: Phe Lys Glu Val Leu Gin Ser Ser Leu Arg Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:23: (l) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:23: Phe Lys Glu Phe Met Gin Ser Ser Leu Arg Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:24: cπ n (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-termmal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:24: Phe Lys Glu Phe Leu Lys Ser Ser Leu Arg Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:25: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO n ( iv ) ANTI-SENSE : NO CO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25: Phe Lys Glu Phe Leu Gin Pro Ser Leu Arg Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:26: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:26: Phe Lys Glu Phe Leu Gin Ser Arg Leu Arg Ala Leu Arg Gin Met 1 5 10 15 cn ^3 (2) INFORMATION FOR SEQ ID NO:27: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:27: (2) INFORMATION FOR SEQ ID NO:28: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide cn 60 (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:28: Phe Lys Glu Phe Leu Gin Ser Ser Leu Lys Ala Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:29: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:29: Phe Lys Glu Phe Leu Gin Ser Ser Leu Arg Asp Leu Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:30: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids cn (B) TYPE: amino acid CO (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:30: ( 2 ) INFORMATION FOR SEQ ID NO : 31 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal °> (xi) SEQUENCE DESCRIPTION: SEQ ID NO:31: O Phe Lys Glu Phe Leu Gin Ser Ser Leu Arg Ala Val Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:32: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (E) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:32: Phe Lys Glu Phe Leu Gin Ser Ser Leu Arg Ala He Arg Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:33: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid cn (C) STRANDEDNESS: single m- (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:33: Phe Lys Glu Phe Leu Gin Ser Ser Leu Arg Ala Leu Trp Gin Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:34: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO 00 (v) FRAGMENT TYPE: C-terminal t (xi) SEQUENCE DESCRIPTION: SEQ ID NO:34: Phe Lys Glu Phe Leu Gin Ser Ser Leu Arg Ala Leu Arg Pro Met 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:35: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO ( iv ) ANTI -SENSE : NO (v) FRAGMENT TYPE: C-terminal (xi) SEQUENCE DESCRIPTION: SEQ ID NO:35: Phe Lys Glu Phe Leu Gin Ser Ser Leu Arg Ala Leu Arg Gin He 1 5 10 15 n OJ

Claims: CLAIMS What is claimed is: 1. A mutein of IL-6 having increased activity wherein the mutei has an amino acid substitution at, or corresponding to, amin acid location 171 or 175 of IL-6 having the wild-type sequence. 2. The mutein of claim 1 wherein the amino acid substitution is at, or corresponds to, amino acid location 171 of IL-6 havin the wild-type sequence. 3. The mutein of claim 1 wherein the amino acid substitution is at, or corresponds to, amino acid location 175 of IL-6 havin the wild-type sequence. 4. The mutein of claim 1 wherein the amino acid substitutions are at, or correspond to, amino acid locations 171 and 175 o IL-6 having the wild-type sequence. 5. The mutein of claim 1 wherein the mutein has up to 28 amino acids deleted from the amino terminal end of the mutein. 6. The mutein of claim 1 wherein the mutein has at least 25 percent greater IL-6 mediated biological activity than that of IL-6 having the wild-type sequence. 7. The mutein of claim 2 wherein the mutein has greater binding capacity for an IL-6 receptor as compared with that of IL-6 having the wild-type sequence. 8. The mutein of claim 3 wherein the mutein has less binding capacity for an IL-6 receptor as compared with that of IL-6 having the wild-type sequence. 9. The mutein of claim 2 wherein the amino acid substitution at, or corresponding to, amino acid location 171 of IL-6 having the wild-type sequence is: Leucine; Isoleucine; Valine or Methionine 10. The mutein of claim 3 wherein the encoded amino acid substitution at, or corresponding to, amino acid location 175 of IL-6 having the wild-type sequence is: Methionine; Isoleucine; or Valine 11. The mutein of claim 1 wherein the mutein has one of the first two cysteine residues removed from the molecule. 12. The mutein of claim 1 wherein the mutein has both of the first two cysteine residues removed from the molecule. 13. A recombinant gene of IL-6 having increased activity wherein the encoded protein has an amino acid substitution at, or corresponding to, amino acid location 171 or 175 of IL-6 having the wild-type sequence. 14. The recombinant gene of claim 13 wherein the amino acid substitution is at, or corresponds to, amino acid location 171 of IL-6 having the wild-type sequence. 15. The recombinant gene of claim 13 wherein the amino acid substitution is at, or corresponds to, amino acid location 175 of IL-6 having the wild-type sequence. 16. The recombinant gene of claim 13 wherein the amino acid substitutions are at, or correspond to, amino acid locations 171 and 175 of recombinant IL-6 having the wild-type sequence. 17. The recombinant gene of claim 13 wherein the encoded protein has up to 28 amino acids deleted from the amino terminal end of the protein. 18. The recombinant gene of claim 13 wherein the encoded protein has at least 25 percent greater IL-6 mediated biological activity than that of IL-6 having the wild-type sequence. 19. The recombinant gene of claim 14 wherein the encoded protein has greater binding capacity for an IL-6 receptor as compared with that of IL-6 having the wild-type sequence. 20. The recombinant gene of claim 15 wherein the encoded protein has less binding capacity for an IL-6 receptor as compared with that of IL-6 having the wild-type sequence. 21. The recombinant gene of claim 14 wherein the encoded amino acid substitution at, or corresponding to, amino acid location 171 of IL-6 having the wild-type sequence is: Leucine; Isoleucine; Valine or Methionine 22. The recombinant gene of claim 15 wherein the encoded amino acid substitution at, or corresponding to, amino acid location 175 of IL-6 having the wild-type sequence is: Methionine; Isoleucine; or Valine 23. The recombinant gene of claim 13 wherein the encoded protein has one of the first two cysteine residues removed from the molecule. 24. The recombinant gene of claim 13 wherein the encoded protein has both of the first two cysteine residues removed from the molecule. 25. A recombinant vector comprising the gene of claim 13. 26. A recombinant vector comprising the gene of claim 14. 27. A recombinant vector comprising the gene of claim 15. 28. A recombinant vector comprising the gene of claim 16. 29. A recombinant vector comprising the gene of claim 17. 30. A recombinant vector comprising the gene of claim 18. 31. A recombinant vector comprising the gene of claim 19. 32. A recombinant vector comprising the gene of claim 20. 33. A recombinant vector comprising the gene of claim 21. 34. A recombinant vector comprising the gene of claim 22. 35. A recombinant vector comprising the gene of claim 23. 36. A recombinant vector comprising the gene of claim 24. 37. The recombinant vector of any one of claims 25 to 36 which is a plasmid. 38. A unicellular host containing the vector of claim 25. 39. A unicellular host containing the vector of claim 26. 40. A unicellular host containing the vector of claim 27. 41. A unicellular host containing the vector of claim 28. 42. A unicellular host containing the vector of claim 29. 43. A unicellular host containing the vector of claim 30. 44. A unicellular host containing the vector of claim 31. 45. A unicellular host containing the vector of claim 32. 46. A unicellular host containing the vector of claim 33. 47. A unicellular host containing the vector of claim 34. 48. A unicellular host containing the vector of claim 35. 49. A unicellular host containing the vector of claim 36. 50. The unicellular host of any one of the claims 38 to 49 which is a prokaryote. 51. The unicellular host of claim 50 which is a bacterium. 52. A method for producing an IL-6 mutein with C-terminal substituted amino acids which comprises: (a) culturing a unicellular host microorganism containing a recombinant gene comprising a nucleotide sequence which encodes a synthetic trihybrid protein that has a first peptide portion having increased IL-6 biological activity, a second peptide portion comprising a protease reaction peptide link between the first peptide portion and a third protein portion having a detectable enzymatic activity, said gene being capable of being replicated, transcribed and translated in the host; (b) identifying proteins produced by the host exhibiting the enzymatic activity of the third protein portion; (c) treating the identified proteins with a protease capable of cleaving the second portion; and (d) recovering the peptide portion having increased IL-6 biological activity. 53. The method of claim 52 wherein the second peptide portion comprises a peptide link which is reactive to a collagenase protease. 54. The method of claim 53 wherein the third protein portion comprises a protein with β-galactosidase enzymatic activity. 55. The method of claim 53 wherein the third protein portion comprises a protein with alkaline phosphatase enzymatic activity. 56. The method of claim 52 or 53 or 54 or 55 wherein the trihybrid protein comprises at least about 20% of total protein produced by the host organism. 57. The method of claim 56 wherein the host is a bacterium. 58. The method of claim 52 or 53 or 54 or 55 wherein the host organism is a prokaryote. 59. The method of claim 58 wherein the host organism is a bacterium. 60. The method of claim 52 or 53 or 54 or 55 wherein the first peptide portion has no sulfhydryl bonds. 61. The method of claim 56 wherein the first peptide portion has no sulfhydryl bonds. 62. The method of claim 57 wherein the first peptide portion has no sulfhydryl bonds.

Inventors: FOWLKES DANA, FOWLKES, DANA
Applicants: UNIV NORTH CAROLINA, THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL
Application year: 1993
Main classification: C07K13
IPC codes: A61K38, C07H21, C07K14, C07K19, C12N15, C12P21, C12R1