WO1994025483A1 - Immunotherapeutic peptides derived from toxic shock syndrome toxin-1, antibodies thereto, their uses in pharmaceutical compositions and diagnosis - Google Patents

Abstract

The invention provides immunogenic peptides, antibodies which bind the peptides, and immunodiagnostic and immunotherapeutic methods using the peptides. In addition, the invention provides antibodies for the diagnosis and treatment of immunopathological disease such as those associated with superantigens.

Description

IMMUNOTHERAPEUTIC PEPTIDES DERIVED FROM TOXIC SHOCK SYNDROME TOXIN-1 ANTIBODIES THERETO. THEIR USES IN PHARMACEUTICAL COMPOSITIONS AND DIAGNOSIS

This application is a Continuation-in-Part of U.S. Patent Serial No. 08/058,518 filed on May 3, 1993.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to immunogenic peptides and specifically to unique immunogenic peptides of the toxic shock syndrome toxin- 1.

2. Description of Related Art

Toxic shock syndrome (TSS) is a multisystem disease, which primarily affects young menstruating women with devastating and potentially lethal consequenc¬ es. Nonmenstrual cases, particularly hospital-acquired, are becoming increasingly recognized. The pathogenesis of this illness remains poorly understood, although studies have clearly identified the causative role of several staphylococcal exoproteins, especially toxic shock syndrome toxin-1 (TSST-1) and related staphylococcal exoproteins are examples of "superantigens". In recent years, there has been considerable scientific interest in this broad family of antigenic proteins

Characteristics of superantigens include substantial T-cell activation and specific interaction with the beta chain variable (Vø) elements of the T-cell receptor. Superantigens bind to major histocompatibility complex (MHC) class II molecules before interaction with the V/3 element of T cells. Before helper T cells can recognize conventional protein antigens, the proteins must first undergo processing by macrophages or other antigen-presenting cells. The presenting cells then display the peptide antigens at the cell surface in combination with MHC class II molecules. Unlike typical antigens, superantig¬ ens bind MHC molecules directly. They do not require uptake and processing as do typical antigens, therefore, T cells can respond to intact toxins. This property of the superantigen is due to the fact that the superantigen does not bind to the inner surface of the MHC molecule, but instead attaches to the outer surface. The superantigen binds to the \Jβ region at a region not typically involved with binding antigens and can activate a great number of both helper and suppressor T-cells bearing a particular Mβ type, whereas conventional antigens can activate only a few helper cells specific for that antigen when presented appropriately by MHC Class II molecules.

Superantigens have unique interactions with both monocytes and T cells, binding to MHC class II molecules (HLA-DR), and activating a broader range of T-cells. Among the most important superantigens are the staphylococcal • exotoxins which include toxic shock syndrome (TSS) toxin-1 (TSST-1). The activation of large numbers of mature T cells is believed to be significant in the pathogenesis of TSS. In addition, TSST-1 is a potent inducer of various lymphokines, such as IL-2 and interferon gamma, from lymphocytes and monokines, such as IL-1 and TNF, from human peripheral blood mononuclear cells (PBMC).

There have been limited structure-function studies of TSST-1. Mitogenic and immunosuppressive activities of the toxin have been localized to a 14 kD CNBr segment (Blomster-Hautamaa, et al., J.lmmunol.. 137(11.:3572. 1986). Modification of tyrosine or histidine residues within the 14 kD fragment results in significant loss of mitogenicity of the fragment (Kokan-Moore, et al., Infect.lmmun., 5Z:1901, 1989; Murphy, et al., J.lnfect.Dis., 158:540, 1988). It has also been determined that a synthetic decapeptide corresponding to the amino-terminus of this 14 kD (residues 34-43) was antigenic and had partial mitogenic activity. However, neither this peptide nor its antibody protected rabbits from TSST-1 induced fever and enhancement of endotoxin shock. Edwin, et al. (Infect.lmmun., 57:2230, 1989) identified two papain digests (12 kD and 16 kD) of TSST-1 which possessed variable antigenic and mitogenic activities. They subsequently synthesized a 21 -mer peptide (residues 58-78) which was found to activate proliferation of human T cells and secretion of TNF from human monocytes (Edwin, et al., J.lnfect.Dis., 163:524, 1991). No in vivo studies with this peptide have been reported. Recently, Bonventre, et al. (Infectlmmun., 61 _3.:793. 1993) reported a possible correlation between in vitro activity of recombinant TSST-1 and several toxin mutants with their in vivo toxicity for rabbits and showed that alanine substitution of histidine 135 or histidine 141 and tyrosine 144 of TSST-1 not only resulted in loss of mitogenic activity but also eliminated the lethal potential of the toxin for rabbits. They concluded that the ability of TSST-1 to induce T-cell proliferation is linked to its lethal toxicity for rabbits.

Superantigens such as TSST-1 bind to MHC class II molecules on monocytes, for example, before interaction with the \lβ element of T cells. However, none of these studies have shown a correlation between MHC receptor binding on monocytes and a particular region of the TSST-1 polypeptide. Identification of the structure-function relationship of various domains of TSST-1 would provide insight into the precise role of this superantigen in the pathogenesis of TSS. The present invention identifies the major antigenic and functional epitopes on the TSST-1 superantigen molecule and provides reagents useful in ameliorating disease processes associated with superantigen-induced pathologies. SUMMARY OF THE INVENTION

The present invention provides unique immunogenic peptides initially identified as residing within the Staphylococcal toxic shock syndrome toxin-1 (TSST-1) polypeptide. These peptides include FPSPYYSPAFTKGE, YYSPAF, STNDNIK- DLLDWYS and FEYNTEKPPINIDEIKTIE and exhibit various biological activities associated with TSST-1 , such as binding to human peripheral blood mononu- clear cells (PBMCs) (MHC Class II molecule), T-cell mitogenicity, induction of hematopoietic cell cytokine secretion, and the lethal effects associated with TSST-1. Since TSST-1 binds to the MHC class II receptor (HLA-DR) on monocytes, the homology with other enterotoxins suggests that this region may define overlapping epitopes of the HLA-DR receptor on human monocytes. Therefore, the peptides of the invention may be implicated in many immuno- pathological diseases.

In another aspect of the invention, monoclonal antibodies which bind to the immunogenic peptides are provided. These antibodies are useful immuno- diagnostically and immunotherapeutically for treating patients with immunopath- ological diseases associated with the peptides of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 shows Western blot analysis of anti-TSST-1 monoclonal antibodies.

FIGURE 2a shows inhibition of ¹²⁵I-TSST-1 binding to human peripheral blood mononuclear cells (PBMC) by TSST-1 monoclonal antibodies.

FIGURE 2b shows inhibition of ¹²⁵I-SEA binding to human PBMC by mAb5.

FIGURE 3a shows inhibition of TSST-1 induced mitogenesis by varying concentrations of different TSST-1 monoclonal antibodies.

FIGURE 3b shows inhibition of SEA induced mitogenesis by mAb5.

FIGURE 4a, b, and c shows inhibition of TSST-1 induced cytokine secretion (TNFα, IL-1 3, and IL-6, respectively, by varying concentrations of different monoclonal antibodies.

FIGURE 5 shows epitope scanning profile of TSST-1 using a rabbit polyclonal anti-TSST-1 antibody.

FIGURE 6 shows mapping of the amino acid sequence of TSST-1 with five antigenic domains defined by rabbit polyclonal TSST-1 antibody (P1-P5) ---, and five domains defined by mAb1-mAb6 (M1-M6) = ==.

FIGURE 7 shows epitope scanning profiles of TSST-1 using the six anti-TSST-1 mAbs: 7a, mAb1 ; 7b, mAb2; 7c, mAb3; 7d, mAb4; 7e, mAb5; 7f, mAb6. FIGURE 8 shows amino acid sequence homology between TSST-1 and Staphylococcal enterotoxins as identified by using the computer search program, MACAW.

FIGURE 9a shows inhibition of ¹²⁵I-TSST-1 binding to human monocytes by the synthetic peptide T(47-60); FIGURE 9b shows inhibition of ¹²⁵I-SEA binding to human monocytes by the synthetic peptide T(47-64). Different concentrations of T(47-60) or T(47-64) were used to inhibit the binding of 3nM of ¹²⁵I-TSST-1 or ²⁵I-SEA respectively to the cells, and were shown to inhibit the binding of either toxin in a dose dependent manner.

FIGURE 10 shows the effect of peptides T(47-60) and T(144-153) on mitogene¬ sis of human PBMC as measured by ³H-thymidine incorporation.

FIGURE 11 a shows inhibition of TSST-1 induced mitogenesis by peptide T(47- 60); FIGURE 11 b shows inhibition of SEA induced mitogenesis by peptide T(47-64). Different concentrations of T(47-60) or T(47-64), respectively, were used to inhibit mitogenesis of human PBMC induced by 0.1 pM of TSST-1 or SEA. The irrelevant peptide T(144-153) had no effect.

FIGURE 12 shows the effect of the peptides T(47-60) and T(144-153) on TNF secretion from co-cultures of human monocytes and T cells (1 :1) as measured by ELISA.

FIGURE 13 shows the inhibition of TSST-1 induced TNFα secretion from co- cultures of human monocytes and T cells (1 :1) by the peptide T(47-60). Different concentrations of T(47-60) were used to inhibit TNFα secretion induced by 4.5 pM of TSST-1. The irrelevant peptide T(144-153) had no effect. DETAILED DESCRIPTION OF THE INVENTION

The present invention provides unique synthetic immunogenic peptides initially identified as residing within staphylococcal toxic shock syndrome toxin-1 (TSST-1). These peptides are implicated in the pathogenesis of TSS and may be involved in other immunopathological diseases. Also included in the invention are antibodies which bind to these peptides. Both the peptides and the monoclonal antibodies which bind to the peptides are useful immunodiagn- ostically and immunotherapeutically to diagnose and treat immunopathological diseases including TSS and other immunopathological disorders.

As used herein, the term "synthetic immunogenic peptide" denotes a peptide which does not comprise an entire naturally occurring protein molecule. These peptides are "synthetic" in that they may be produced by human intervention using such techniques as chemical synthesis, recombinant genetic techniques, or fragmentation of whole antigen or the like. "Immunogenic" means that the peptides of the invention can participate in an immune response. This participation can be, for example, either passive or active participation. Thus, the peptides can be passively utilized, for example, by interacting in vitro or in vivo with antibody which binds to an epitope located in the peptide. Alternatively, the peptides can be used actively, for example, to induce an immune response in a host.

The term "immunopathological disease" or "immunopathological disorder" refers to any disease which involves the immune response or immunity in general. The term "TSST-1 associated" or "superantigen associated" disease means any disease which is directly or indirectly caused or associated with the novel peptide sequences of the invention, whether found in TSST-1 or any other superantigen. Examples of superantigens include toxic shock syndrome toxin- 1 , Staphylococcus enterotoxins and Streptococcus pyrogenic exotoxins. Staphylococcus enterotoxins include SEA, SEB, SEC1 , SEC3, SED, and SEE for example. Examples of immunopathological diseases include toxic shock syndrome (TSS), rheumatoid arthritis, systemic lupus erthematosus (SLE), sepsis syndrome, acquired immune deficiency syndrome (AIDS) and various malignancies.

The peptides of the invention range in length from about 14 to about 19 amino acids and include amino acid sequences FPSPYYSPAFTKGE (SEQ ID NO:1), STNDNIKDLLDWYS (SEQ ID NO:2) and FEYNTEKPPINIDEIKTIE (SEQ ID NO:3) which correspond to amino acid residues 47-60, 1-14, and 172-190 of TSST-1 , respectively. The entire TSST-1 polypeptide is 194 amino acid residues in length. The peptide FPSPYYSPAFTKGE binds to human PBMCs (MHC Class II molecule), has T-cell mitogenicity, induces hematopoietic cell cytokine secretion, and possesses the lethal effects associated with TSST-1. This peptide is probably the critical domain for both the superantigenic and lethal effects of the TSST-1 molecule. More specifically, residues 51-56 of TSST-1 , or residues 5-10 of SEQ ID NO:1 , YYSPAF, correspond to the superantigen critical domain. Thus, the peptides of the invention include those of structure X-_jYYSPAFXg, wherein X₁ or X_g are independently 0 to about 10 amino acids in length, most preferably 0 to about 4 amino acids in length, and such polypeptides retain the activity of SEQ ID NO:1. Not only does the SEQ ID

NO:1 peptide inhibit TSST-1 binding to monocytes and block TSST-1 induced mitogenesis and cytokine secretion, it also inhibits SEA binding to monocytes and blocks SEA-induced mitogenesis. The peptides STNDNIKDLLDWYS and FEYNTEKPPINIDEIKTIE exhibit T-cell mitogenicity associated with TSST-1.

Minor modifications of the primary amino acid sequence of the peptides of the invention may result in peptides which have substantially equivalent activity as compared to the specific peptides described herein. Such modifications may be deliberate, as by site-directed mutagenesis, or may be spontaneous. All of the peptides produced by these modifications are included herein as long as the biological activity of the peptide of the invention still exists. For example, the TSST-polypeptide or peptide of SEQ ID NO:1 still acts as a competitive inhibitor for the natural TSST-1 in its binding to human monocytes or to the monoclonal antibody, mAb5, indicating that the peptide has binding affinity for the same receptors as natural TSST-1.

The invention also provides "variants" of native TSST-1 wherein at least one amino acid residue in positions 51 through 56 from the amino terminus of native TSST-1 are substituted with a non-native amino acid residue. Preferred is a TSST-1 variant, in which amino acid residue 55 of wild-type or native TSST- 1 (SEQ ID NO:4) is modified by site directed mutagenesis. A preferred amino acid substitution at residue 55 is with an amino acid threonine, asparagine, and glutamine. Most preferred is substitution of alanine with threonine at residue 55. The TSSF-1 variants of the invention bind poorly with monoclonal antibody mAb5, are not mitogenic and do not induce cytokine secretion. However, a variant containing this modification is fully functional in being able to inhibit binding of native TSST-1 to human monocytes and in blocking TSST-1 induced mitogenesis and cytokine secretion. Thus, the invention includes variants which encompass the region of the wild type TSST molecule wherein residue 55 is changed from alanine to threonine, or a functional analog of threonine, such as glutamine or asparagine which also possess a polar side chain. Other similar amino acid modifications of the peptides of the invention may also block the biological activity native TSST-1.

Further, deletion of one or more amino acids can also result in a modification of the structure of the resultant molecule without significantly altering its biological activity. This can lead to the development of a smaller active molecule which would also have utility. For example, one can remove amino or carboxy terminal amino acids which may not be required for biological activity of the particular peptide.

The term "conservative variation" as used herein denotes the replacement of an amino acid residue by another, biologically similar residue. Examples of conservative variations include the substitution of one hydrophobic residue such as isoleucine, valine, leucine or methionine for another, or the substitution of one polar residue for another, such as the substitution of arginine for lysine, glutamic for aspartic acids, or glutamine for asparagine, and the like. The term "conservative variation" also includes the use of a substituted amino acid in place of an unsubstituted parent amino acid provided that antibodies raised to the substituted polypeptide also immunoreact with the unsubstituted polypep- tide.

Peptides of the invention can be synthesized by such commonly used methods as t-BOC or FMOC protection of alpha-amino groups. Both methods involve stepwise syntheses whereby a single amino acid is added at each step starting from the C terminus of the peptide (See, Coligan, et al., Current Protocols in Immunology, Wiley Interscience, 1991 , Unit 9). Peptides of the invention can also be synthesized by the well known solid phase peptide synthesis methods described Merrifield, J. Am. Chem. Soα, 85:2149, 1962), and Stewart and Young, Solid Phase Peptides Synthesis, (Freeman, San Francisco, 1969, pp.27- 62), using a copoly(styrene-divinylbenzene) containing 0.1-1.0 mMol amines/g polymer. On completion of chemical synthesis, the peptides can be deprotec- ted and cleaved from the polymer by treatment with liquid HF-10% anisole for about 1/4-1 hours at 0°C. After evaporation of the reagents, the peptides are extracted from the polymer with 1% acetic acid solution which is then lyophilized to yield the crude material. This can normally be purified by such techniques as gel filtration on Sephadex G-15 using 5% acetic acid as a solvent. Lyophilization of appropriate fractions of the column will yield the homogeneous peptide or peptide derivatives, which can then be characterized by such standard techniques as amino acid analysis, thin layer chromatogra- phy, high performance liquid chromatography, ultraviolet absorption spectros- copy, molar rotation, solubility, and quantitated by the solid phase Edman degradation.

The peptides of the invention can be used singularly, in mixtures, or as multimers such as aggregates, polymers, and the like. Thus, the invention embraces synthetic peptides which comprise one or more of the same, or different, peptides of the invention to produce a homogeneous or heteroge- neous polymer with respect to the particular peptides of the invention which are contained therein. Appropriate techniques for producing various mixtures, aggregates, multimers and the like will be known to those of skill in the art. For example, the invention would include a polypeptide comprising SEQ ID NO:1 and SEQ ID NO: 2 or NO:3 or both, wherein SEQ ID NO: 1, SEQ ID NO:2 and/or SEQ ID NO:3 are linked directly or indirectly, for example, by using a spacer or linker moiety. Techniques for utilizing spacer or linker moieties are well known in the art.

The invention also provides polynucleotides which encode the peptides of the invention. As used herein, "polynucleotide" refers to a polymer of deoxyribo- nucleotides or ribonucleotides, in the form of a separate fragment or as a component of a larger construct. DNA encoding a peptide of the invention can be assembled from cDNA fragments or from oligonucleotides which provide a synthetic gene which is capable of being expressed in a recombinant transcriptional unit. Polynucleotide sequences of the invention include DNA, RNA and cDNA sequences. A polynucleotide sequence can be deduced from the genetic code, however, the degeneracy of the code must be taken into account. Polynucleotides of the invention include sequences which are degenerate as a result of the genetic code. Polynucleotide sequences encoding the peptides or TSST-1 variant of the invention can be expressed in either prokaryotes or eukaryotes. Hosts can include microbial, yeast, insect and mammalian organisms. Methods of expressing DNA sequences having eukaryotic or viral sequences in prokaryo- tes are well known in the art. Biologically functional viral and plasmid DNA vectors capable of expression and replication in a host are known in the art. Such vectors are used to incorporate DNA sequences of the invention.

In order to express a biologically active peptide or TSST-1 variant of the invention, the nucleotide sequence encoding the peptide or variant, or a functionally equivalent nucleotide sequence, is inserted into an appropriate expression vector, i.e., a vector which contains the necessary elements for the transcription and translation of the inserted coding sequence. Modified versions of the coding sequence can be engineered to enhance stability, production, purification or yield of the expressed product. For example, the expression of a fusion protein or a cleavable fusion protein comprising the peptide or variant and a heterologous protein may be engineered. Such a fusion protein may be readily isolated by affinity chromatography; e.g. by immobilization on a column specific for the heterologous protein. Where a cleavage site is engineered between the peptide or variant moiety and the heterologous protein, the peptide or variant can be released from the chromatographic column by treatment with an appropriate enzyme or agent that disrupts the cleavage site (Booth, et al., Immunol. Lett. 19:65-70, 1988; and Gardella, et al., J. Biol. Chem. 265:15854-15859, 1990).

Those skilled in the art will recognize that, due to the degeneracy of the genetic code, a variety of DNA compounds can encode a peptide or variant of the invention. Such nucleotide sequences are considered functionally equivalent since they can result in the production of the same amino acid residue sequence. Occasionally, a methylated variant of a purine or pyrimidine may be incorporated into a given nucleotide sequence. However, such minor modification does not significantly effect the coding relationship and are embraced by the present invention as long as the resulting peptide or variant possess the properties of the peptide or variant of the invention. Consequent- ly, the constructions described herein for DNA compounds, vectors, and transformants of the invention are merely illustrative and do not limit the scope of the invention.

Methods which are well known to those skilled in the art can be used to construct expression vectors containing the peptide or variant coding sequence and appropriate transcriptional/translational control signals. These methods include in vitro recombinant DNA techniques, synthetic techniques, and in vivo recombination/genetic techniques (Maniatis, et al., Molecular Cloning A Laboratory Manual, Cold Spring Harbor Laboratory, N.Y., 1989.)

A variety of host-expression vector systems may be utilized to express the- peptide or variant coding sequence. These include, but are not limited to, microorganisms such as bacteria transformed with recombinant bacteriophage DNA, plasmid DNA or cosmid DNA expression vectors containing the peptide or variant coding sequence; yeast transformed with recombinant yeast expression vectors containing the peptide or variant coding sequence; plant cell systems infected with recombinant virus expression vectors (e.g., cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or transformed with recombinant plasmid expression vectors (e.g., Ti plasmid) containing the peptide or variant coding sequence; insect cell systems infected with recombinant virus expression vectors (e.g., baculovirus) containing the peptide or variant coding sequence; or animal cell systems infected with recombinant virus expression vectors (e.g., retroviruses, adenovirus, vaccinia virus) containing the peptide or variant coding sequence, or transformed animal cell systems engineered for stable expression. Depending on the host/vector system utilized, any of a number of suitable transcription and translation elements, including constitutive and inducible promoters, transcription enhancer elements, transcription terminators, and so forth, may be used in the expression vector (see e.g., Bitter, et al., Methods in Enzymology 153:516-544, 1987). For example, when cloning in bacterial systems, inducible promoters such as pL of bacteriophage λ, plac, ptrp, ptac (ptrp-lac hybrid promoter) and the like may be used. When cloning in mammalian cell systems, promoters derived from the genome of mammalian cells (e.g., metallothionein promoter) or from mammalian viruses (e.g., the retrovirus long terminal repeat; the adenovirus late promoter; the vaccinia virus 7.5K promoter) may be used. Promoters produced by recombinant DNA or synthetic techniques may also be used to provide for transcription of the inserted specific peptide or variant coding sequence.

In bacterial systems a number of expression vectors may be advantageously selected depending upon the use intended for the peptide or variant expressed. For example, when large quantities of peptide or variant are to be produced, vectors which direct the expression of high levels of fusion protein products that are readily purified may be desirable. Those which are engineered to contain a cleavage site to aid in recovering peptide or variant are preferred. Such vectors include but are not limited to the E. coli expression vector pUR278 (Ruther, et al., EMBO J. 2:1791 , 1983), in which the peptide or variant coding sequence may be ligated into the vector in frame with the lac Z coding region so that a hybrid peptide or variant-lac Z protein is produced; pIN vectors (Inouye & Inouye, Nucleic acids Res. 13:3101-3109, 1985; Van Heeke & Schuster, J. Biol. Chem. 264:5503-5509, 1989); and the like.

In yeast, a number of vectors containing constitutive or inducible promoters may be used. For a review see, Current Protocols in Molecular Biology, Vol. 2, 1988, Ed. Ausubel, et al., Greene Publish. Assoc. & Wiley Interscience, Ch. 13; Grant, et al., Expression and Secretion Vectors for Yeast, in Methods in Enzymology, Eds. Wu & Grossman, 31987, Acad. Press, N.Y., 153:516-544. 1987; Glover, DNA Cloning, Vol. II, IRL Press, Wash., D.C., Ch. 3, 1986; and Bitter, 1987, Heterologous Gene Expression in Yeast, Methods in Enzymology,

Eds. Berger & Kimmel, Acad. Press, N.Y., 152:673-684: and The Molecular Biology of the Yeast Saccharomyces, 1982, Eds. Strathern, et al., Cold Spring Harbor Press, Vols. I and II. A constitutive yeast promoter such as ADH or LEU2 or an inducible promoter such as GAL may be used (Cloning in Yeast, Ch. 3, R. Rothstein In: DNA Cloning Vol.11, A Practical Approach, Ed. DM Glover, 1986, IRL Press, Wash., D.C.). Alternatively, vectors may be used which promote integration of foreign DNA sequences into the yeast chromo¬ some.

In cases where plant expression vectors are used, the expression of the peptide or variant coding sequence may be driven by any of a number of promoters. For example, viral promoters such as the 35S RNA and 19S RNA promoters of CaMV (Brisson, et al., Nature 310:511-514, 1984), or the coat protein promoter to TMV (Takamatsu, et al., EMBO J. 6:307-311 , 1987) may be used; alternatively, plant promoters such as the small subunit of RUBISCO (Coruzzi, et al., EMBO J. 3:1671-1680, 1984; Broglie, et al., Science 224:838-

843, 1984); or heat shock promoters, e.g., soybean hsp17.5-E or hsp17.3-B

(Gurley, et al., Mol. Cell. Biol. 6:559-565, 1986) may be used. These constructs can be introduced into plant cells using Ti plasmids, Ri plasmids, plant virus vectors, direct DNA transformation, microinjection, electroporation, etc. (Weissbach & Weissbach, 1988, Methods for Plant Molecular Biology,

Academic Press, NY, Section VIII, pp. 421-463; and Grierson & Corey, 1988,

Plant Molecular Biology, 2d Ed., Blackie, London, Ch. 7-9.) An alternative expression system which could be used to express the peptide or variant of the invention is an insect system. In one such system, Autographa californica nuclear polyhedrosis virus (AcNPV) is used as a vector to express foreign genes. The virus grows in Spodoptera frugiperda cells. The peptide or variant coding sequence may be cloned into non-essential regions (for example, the polyhedrin gene) of the virus and placed under control of an AcNPV promoter (for example, the polyhedrin promoter). Successful insertion of the peptide or variant coding sequence will result in inactivation of the polyhedrin gene and production of non-occluded recombinant virus (i.e., virus lacking the proteinaceous coat coded for by the polyhedrin gene). These recombinant viruses are then used to infect Spodoptera frugiperda cells in which the inserted gene is expressed. (Smith, et al., J. Viol. 46:584, 1983; Smith, U.S. Patent No. 4,215,051).

Eukaryotic systems, and preferably mammalian expression systems, allow for proper post-translational modifications of expressed mammalian proteins to occur. Eukaryotic cells which possess the cellular machinery for proper processing of the primary transcript, glycosylation, phosphorylation, and advantageously, secretion of the gene product may be used as host cells for the expression of peptide or variant. Mammalian cell lines may be preferable. Such host cell lines may include but are not limited to CHO, VERO, BHK, HeLa, COS, MDCK, -293, and WI38.

Mammalian cell systems which utilize recombinant viruses or viral elements to direct expression may be engineered. For example, when using adenovirus expression vectors, the peptide or variant coding sequence may be ligated to an adenovirus transcription/translation control complex, e.g., the late promoter and tripartite leader sequence. This chimeric gene may then be inserted in the adenovirus genome by in vitro or in vivo recombination. Insertion in a non- essential region of the viral genome (e.g., region E1 or E3) will result in a recombinant virus that is viable and capable of expressing the peptide or variant in infected hosts (Logan & Shenk, Proc. Natl. Acad. Sci. USA, 81:3655- 3659, 1984). Alternatively, the vaccinia virus 7.5K promoter may be used. (Mackett, et al., Proc. Natl. Acad. Sci. USA, 79:7415-7419, 1982; Mackett, et al., J. Virol., 49:857-864, 1984; Panicali, et al., Proc. Natl. Acad. Sci. USA, 29:4927- 4931 , 1982). Of particular interest are vectors based on bovine papilloma virus which have the ability to replicate as extrachromosomal elements (Sarver, et al., Mol. Cell. Biol., 1:486, 1981). Shortly after entry of this DNA into mouse cells, the plasmid replicates to about 100 to 200 copies per cell. Transcription of the inserted cDNA does not require integration of the plasmid into the host's chromosome, thereby yielding a high level of expression. These vectors can be used for stable expression by including a selectable marker in the plasmid, such as, for example, the neo gene. Alternatively, the retroviral genome can be modified for use as a vector capable of introducing and directing the expression of the peptide or variant coding sequence in host cells (Cone & Mulligan, Proc. Natl. Acad. Sci. USA, 81:6349-6353, 1984). High level expression may also be achieved using inducible promoters, including, but not limited to, the metallothionine HA promoter and heat shock promoters.

For long-term, high-yield production of recombinant proteins, stable expression is preferred. Rather than using expression vectors which contain viral origins of replication, host cells can be transformed with the peptide or variant coding sequence controlled by appropriate expression control elements (e.g., promoter, enhancer, sequences, transcription terminators, polyadenylation sites, etc.), and a selectable marker. The selectable marker in the recombinant plasmid confers resistance to the selection and allows cells to stably integrate the plasmid into their chromosomes and grow to form foci which in turn can be cloned and expanded into cell lines. For example, following the introduction of foreign DNA, engineered cells may be allowed to grow for 1 -2 days in an enriched media, and then are switched to a selective media. A number of selection systems may be used, including but not limited to the herpes simplex virus thymidine kinase (Wigler, et al., Cell, 11:223, 1977), hypoxanthine-guanine phosphoribosyltransferase (Szybalska & Szybalski, Proc. Natl. Acad. Sci. USA, 48:2026, 1962), and adenine phosphoribosyltransferase (Lowy, et al., Cell, 22:817, 1980) genes can be employed in tk^", hgprf or aprf cells respectively. Also, antimetabolite resistance can be used as the basis of selection for DHFR, which confers resistance to methotrexate (Wigler, et al., Natl. Acad. Sci. USA, ZZ:3567, 1980; O'Hare, et al., Proc. Natl. Acad. Sci. USA, 78: 1527, 1981); gpt, which confers resistance to mycophenolic acid (Mulligan & Berg, Proc. Natl. Acad. Sci. USA, 78:2072, 1981 ; neo, which confers resistance to the aminoglyc- oside G-418 (Colberre-Garapin, et al., J. Mol. Biol., 150:1. 1981); and hygro, which confers resistance to hygromycin (Santerre, et al., Gene 30:147, 1984) genes. Additional selectable genes have been described, namely trpB, which allows cells to utilize indole in place of tryptophan; hisD, which allows cells to utilize histinol in place of histidine (Hartman & Mulligan, Proc. Natl. Acad. Sci. USA, 85:8047, 1988); and ODC (ornithine decarboxylase) which confers resistance to the ornithine decarboxylase inhibitor, 2-(difluoromethyl)-DL- omithine, DFMO (McConlogue L., 1987, In: Current Communications in Molecular Biology, Cold Spring Harbor Laboratory ed.).

A peptide or variant of the invention can be isolated from the conditioned media of continuous cell lines and purified to homogeneity using a variety of protein purification procedures. Alternatively, the peptide or variant may be produced by recombinant DNA techniques, or by chemical synthesis methods.

Peptide or variant of the invention may be purified from culture supernatants of cells that secrete it, such as genetically engineered recombinant host cell expression systems. Peptide or variant may also be purified by immunoaffinity methods using an anti-peptide or variant antibody. In addition, peptide or variant may be purified using isoelectric focusing methods. Methods for purifying peptide or variant from crude culture media of cells may be adapted for purification of the cloned, expressed product. In addition, where the peptide or variant coding sequence is engineered to encode a cleavable fusion protein, the purification of peptide or variant may be readily accomplished using affinity purification techniques. For example, a peptide or variant factor Xa cleavage recognition sequence can be engineered between the carboxyl terminus of the peptide or variant and a maltose binding protein. The resulting fusion protein can be readily purified using a column conjugated with amylose to which the maltose binding protein binds. The peptide or variant fusion protein is then eluted from the column with maltose containing buffer followed by treatment with Factor Xa. The cleaved peptide or variant is further purified by passage through a second amylose column to remove the maltose binding protein (New England Biolabs, Beverly, MA). Using this aspect of the invention, any cleavage site or enzyme cleavage substrate sequence may be engineered between the peptide or variant sequence and a second peptide or protein that has a binding partner which could be used for purification, e.g., any antigen for which an immunoaffinity column can be prepared.

Procedures which may be used to isolate the peptide or variant of the invention include those commonly used for the separation of protein substances including, for example, treatment of a sample containing the peptide or variant with common precipitants for proteins, followed by fractionation techniques such as ion exchange chromatography, affinity chromatography, ultrafiltration and various combinations thereof. Specific peptide or variant can be purified from a cell suspension by methods described in U.S. Patent Nos. 4,885,236 and 4,882,268, for example. Other methods for purification of the polypeptide of the invention will be known to those of skill in the art (Current Protocols in Immunology, Coligan, et al., eds., 1992, incorporated herein by reference) A nucleotide sequence which encodes peptide or variant can be isolated using several methods described herein, and the appropriate amino acid substitutions can then be made by mutagenesis techniques commonly known in the art. For example, the amino acid substitutions can be made using the duf ung^" technique of Kunkel, et al., (Proc. Natl. Acad. Sci., U.S.A., 82:488, 1985) oligonucleotide-directed mutagenesis, region-specific mutagenesis, linker- scanning mutagenesis, or oligonucleotide-directed mutagenesis that utilizes the polymerase chain reaction (PCR) (See Ausubel, et al., Current Protocols in Molecular Biology, Wiley Interscience, 1989, Unit 8).

The peptide or variant molecule may also be produced in whole or in part by solid phase chemical synthetic techniques based on its amino acid sequence. (Creighton, 1983, Proteins Structures and Molecular Principles, W.H. Freeman and Co., N.Y. pp. 50-60; Stewart and Young, 1984, Peptide Synthesis, 2nd ed., Pierce Chemical Co.). This approach may be particularly useful in generating segments of peptide or variant corresponding to one or more of its biologically active regions.

Those skilled in the art recognize that a great number of promoters, enhancers, and expression vectors are known in the art and can be used in the method of the present invention. The key aspect of the present invention does not reside in the particular enhancer, if any, or promoter, used to drive expression of the peptide or variant, but rather, resides in the novel coding sequence and corresponding proteins produced from that sequence.

In another aspect, the present invention is directed to polyclonal and monoclonal antibodies which bind to the peptides of the invention. Antibody which consists essentially of pooled monoclonal antibodies with different epitopic specificities, as well as distinct monoclonal antibody preparations are provided. Monoclonal antibodies are made from antigen containing fragments of the protein by methods well known in the art (Kohler, et al., Nature, 256:495, 1975; Current Protocols in Molecular Biology, Ausubel, et aL, ed., 1989). The term "antibody" as used in this invention includes intact molecules as well as fragments thereof, such as Fab, F(ab')₂, and Fv which are capable of binding the epitopic determinant.

As used in this invention, the term "epitope" means any antigenic determinant on an antigen to which the paratope of an antibody binds. Epitopic determi¬ nants usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains and usually have specific three dimension- al structural characteristics, as well as specific charge characteristics.

Antibodies which bind to the peptides of the invention can be prepared using an intact polypeptide or fragments containing the peptides of interest as the immunizing antigen. A peptide used to immunize an animal can be derived from translated cDNA or chemical synthesis and is purified and conjugated to a carrier protein, if desired. Such commonly used carriers which are chemically coupled to the peptide include keyhole limpet hemocyanin (KLH), thyroglobulin, bovine serum albumin (BSA), and tetanus toxoid. The coupled peptide is then used to immunize the animal.

If desired, polyclonal antibodies can be further purified, for example, by binding to and elution from a matrix to which the peptide to which the antibodies were raised against is bound. Those of skill in the art will know of various techniques common in the immunology arts for purification and/or concentra¬ tion of polyclonal antibodies, as well as monoclonal antibodies (See for example, Coligan, et al., Unit 9, Current Protocols in Immunology, Wiley Interscience, 1991 , incorporated by reference). Methods known in the art allow antibody exhibiting binding for a preselected ligand to be identified and isolated from antibody expression libraries. This methodology can also be applied to hybridoma cell lines expressing mono¬ clonal antibodies with binding for a preselected ligand. Hybridomas which secrete a desired monoclonal antibody can be produced in various ways using techniques well understood by those having ordinary skill in the art and will not be repeated here. Details of these techniques are described in such references as Monoclonal Antibodies-Hybridomas: A New Dimension in Biological Analysis, Edited by Roger H. Kennett, et al., Plenum Press, 1980; and U.S. 4,172,124, incorporated by reference.

Another method for the identification and isolation of an antibody binding domain which exhibits binding with a peptide of the invention is the bacterio¬ phage λ vector system. This vector system has been used to express a combinatorial library of Fab fragments from the mouse antibody repertoire in Escherichia coli (Huse, et al., Science, 246:1275-1281 , 1989) and from the human antibody repertoire (Mullinax, et al., Proc. Natl. Acad. Sci., 87:8095- 8099, 1990). As described therein, antibody exhibiting binding for a preselect¬ ed ligand were identified and isolated from these antibody expression libraries. This methodology can also be applied to hybridoma cell lines expressing monoclonal antibodies with binding for a preselected ligand. Hybridomas which secrete a desired monoclonal antibody can be produced in various ways using techniques well understood by those having ordinary skill in the art and will not be repeated here. Details of these techniques are described in such references as Monoclonal Antibodies-Hybridomas: A New Dimension in Biological Analysis, Edited by Roger H. Kennett, et al., Plenum Press, 1980; and U.S. 4,172,124.

In addition, methods of producing chimeric antibody molecules with various combinations of "humanized" antibodies are known in the art and include combining murine variable regions with human constant regions (Cabily, et al. Proc.Natl.Acad.Sci. USA, 81:3273, 1984), or by grafting the murine-antibody complementary determining regions (CDRs) onto the human framework (Riechmann, et al., Nature 332:323, 1988).

The monoclonal antibodies of the invention are immunoreactive and bind with the peptides of the invention. One monoclonal antibody (mAb5; ATCC HB 11475) binds to a peptide corresponding to amino acid residues 47-60 of TSST-1 (FPSPYYSPAFTKGE) which contains a T-cell mitogenic site, a binding site for human PBMCs (MHC class II receptor), a hematopoietic cell cytokine secretion induction site and a neutralization site for the lethal effects associated with TSST-1. This monoclonal antibody inhibits T-cell mitogenicity of the native toxin, blocks binding of the toxin to the MHC receptor on monocytes, inhibits cytokine secretion due to the action of the native toxin on cells and neutralizes the lethal effects of the native toxin agains animals. In addition, this monoclonal antibody inhibits SEA binding to human monocytes and SEA induced mitogenicity. A second antibody (mAb1 ; ATCC HB 11473) binds to a peptide which corresponds to amino acid residues 1-14 of TSST-1 (STNDNIKDLLDWYS) and which peptide which contains a T-cell mitogenic site and a third antibody (mAb 4; ATCC HB 11474) binds to the region of TSST-1 corresponding to amino acids 172-190 (FEYNTEKPPINIDEIKTIE) of the C- terminus, which contains a T-cell mitogenic site. Both of these latter two antibodies (i.e., ATCC HB 11473 and ATCC HB 11474) inhibit T-cell mitogenici¬ ty associated with the peptides.

The invention also provides cell lines which produce such antibodies. The isolation of cell lines producing monoclonal antibodies of the invention can be accomplished using routine screening techniques which permit determination of the elementary reaction pattern of the monoclonal antibody of interest. Thus, if a monoclonal antibody being tested binds and neutralizes the activity associated with the specific peptide, then the monoclonal antibody being tested and the monoclonal antibody produced by the cell lines of the invention are equivalent.

It is also possible to determine, without undue experimentation, if a monoclonal antibody has the same specificity as a monoclonal antibody of the invention by ascertaining whether the former prevents the latter from binding to the peptide. If the monoclonal antibody being tested competes with the monoclonal antibody of the invention, as shown by a decrease in binding by the monoclo¬ nal antibody of the invention, then it is likely that the two monoclonal antibodies bind to the same, or a closely related, epitope.

In addition, a monoclonal antibody may bind to an epitope overlapping the epitope to which a monoclonal antibody of the invention binds. Again, one skilled in the art would be able to determine if the former prevents the latter from binding to the peptide. For example, a monoclonal antibody which binds to an epitope that includes amino acids 58-60 of TSST-1 (from the amino terminus of SEQ ID NO:4) may sterically inhibit a monoclonal antibody of the invention.

Still another way to determine whether a monoclonal antibody has the specificity of a monoclonal antibody of the invention is to pre-incubate the monoclonal antibody being tested with the peptide to which the antibody is presumed to be reactive, and then add the monoclonal antibody of the invention to determine if the monoclonal antibody of the invention is inhibited in its ability to bind the peptide. If the monoclonal antibody of the invention is inhibited then, in all likelihood, the monoclonal antibody being tested has the same, or functionally equivalent, epitopic specificity as the monoclonal antibody of the invention. Screening of monoclonal antibodies of the invention, can be also carried out utilizing the peptides and determining whether the monoclonal antibody neutralizes TSST-1 toxic or mitogenic activity.

By using the monoclonal antibodies of the invention, it is now possible to produce anti-idiotypic antibodies which can be used to screen monoclonal antibodies to identify whether the antibody has the same binding specificity as a monoclonal antibody of the invention. These antibodies can also be used for immunization purposes (Herlyn, et al., Science, 232:100, 1986). Such anti- idiotypic antibodies can be produced using well-known hybridoma techniques (Kohler and Milstein, Nature, 256:495, 1975). An anti-idiotypic antibody is an antibody which recognizes unique determinants present on the monoclonal antibody produced by the cell line of interest. These determinants are located in the hypervariable region of the antibody. It is this region (paratope) which binds to a given epitope and, thus, is responsible for the specificity of the antibody. An anti-idiotypic antibody can be prepared by immunizing an animal with the monoclonal antibody of interest. The immunized animal will recognize and respond to the idiotypic determinants of the immunizing antibody and produce an antibody to these idiotypic determinants. By using the anti- idiotypic antibodies of the immunized animal, which are specific for a monoclonal antibody of the invention produced by a cell line which was used to immunize the second animal, it is now possible to identify other clones with the same idiotype as the antibody of the hybridoma used for immunization. Idiotypic identity between monoclonal antibodies of two cell lines demonstrates that the two monoclonal antibodies are the same with respect to their recognition of the same epitopic determinant. Thus, by using anti-idiotypic antibodies, it is possible to identify other hybridomas expressing monoclonal antibodies having the same epitopic specificity.

It is also possible to use the anti-idiotype technology to produce monoclonal antibodies which mimic an epitope. For example, an anti-idiotypic monoclonal antibody made to a first monoclonal antibody will have a binding domain in the hypervariable region which is the "image" of the epitope bound by the first monoclonal antibody. Thus, the anti-idiotypic monoclonal antibody can be used for immunization, since the anti-idiotype monoclonal antibody binding domain effectively acts as an antigen.

The monoclonal antibodies of the invention are suited in vitro for use, for example, in immunoassays in which they can be utilized in liquid phase or bound to a solid phase carrier. In addition, the monoclonal antibodies in these immunoassays can be detectably labeled in various ways. Examples of types of immunoassays which can utilize monoclonal antibodies of the invention are competitive and non-competitive immunoassays in either a direct or indirect format. Examples of such immunoassays are the radioimmunoassay (RIA) and the sandwich (immunometric) assay. Detection of the antigens using the monoclonal antibodies of the invention can be done utilizing immunoassays which are run in either the forward, reverse, or simultaneous modes, including immunohistochemical assays on physiological samples. Those of skill in the art will know, or can readily discern, other immunoassay formats without undue experimentation.

The monoclonal antibodies of the invention can be bound to many different carriers and used to detect the presence of TSST-1 or other superantigens or polypeptides which contain a peptide of the invention. Examples of well-known carriers include glass, polystyrene, polypropylene, polyethylene, dextran, nylon, amylases, natural and modified celluloses, polyacrylamides, agaroses and magnetite. The nature of the carrier can be either soluble or insoluble for purposes of the invention. Those skilled in the art will know of other suitable carriers for binding monoclonal antibodies, or will be able to ascertain such, using routine experimentation. There are many different labels and methods of labeling known to those of ordinary skill in the art. Examples of the types of labels which can be used in the present invention include enzymes, radioisotopes, fluorescent compounds, colloidal metals, chemiluminescent compounds, and bio-luminescent com- pounds. Those of ordinary skill in the art will know of other suitable labels for binding to the monoclonal antibodies of the invention, or will be able to ascertain such, using routine experimentation. Furthermore, the binding of these labels to the monoclonal antibodies of the invention can be done using standard techniques common to those of ordinary skill in the art.

For purposes of the invention, TSST-1 , or other superantigens or polypeptides which contain a peptide of the invention may be detected by the monoclonal antibodies of the invention when present in biological fluids and tissues. Any sample containing a detectable amount of superantigen can be used. A sample can be a liquid such as urine, saliva, cerebrospinal fluid, blood, serum and the like, or a solid or semi-solid such as tissues, feces, and the like, or, alternatively, a solid tissue such as those commonly used in histological diagnosis.

Another labeling technique which may result in greater sensitivity consists of coupling the antibodies to low molecular weight haptens. These haptens can then be specifically detected by means of a second reaction. For example, it is common to use haptens such as biotin, which reacts with avidin, or dinitrophenol, pyridoxal, or fluorescein, which can react with specific anti-hapten antibodies.

The monoclonal antibodies of the invention can also be used for in vivo diagnosis, such as to identify a site of infection or to monitor antibiotic therapy.

In using the monoclonal antibodies of the invention for the in vivo detection of antigen having a peptide of the invention, the detectably labeled monoclonal antibody is given in a dose which is diagnostically effective. The term "diagnostically effective" means that the amount of detectably labeled monoclonal antibody is administered in sufficient quantity to enable detection of the site having a TSST-1 or other antigen for which the monoclonal anti- bodies bind by virtue of the presence of the particular polypeptide of the invention.

The concentration of detectably labeled monoclonal antibody which is administered should be sufficient such that the binding to a peptide of the invention is detectable compared to the background. Further, it is desirable that the detectably labeled monoclonal antibody be rapidly cleared from the circulatory system in order to give the best target-to-background signal ratio.

As a rule, the dosage of detectably labeled human monoclonal antibody for in vivo diagnosis will vary depending on such factors as age, sex, and extent of disease of the individual. The dosage of human monoclonal antibody can vary from about 0.01 mg/m² to about 500 mg/m², preferably 0.1 mg/m² to about 200 mg/m², most preferably about 0.1 mg/m² to about 10 mg/m². Such dosages may vary, for example, depending on whether multiple injections are given, tissue, and other factors known to those of skill in the art.

For in vivo diagnostic imaging, the type of detection instrument available is a major factor in selecting a given radioisotope. The radioisotope chosen must have a type of decay which is detectable for a given type of instrument. Still another important factor in selecting a radioisotope for in vivo diagnosis is that the half-life of the radioisotope be long enough so that it is still detectable at the time of maximum uptake by the target, but short enough so that deleteri- ous radiation with respect to the host is minimized. Ideally, a radioisotope used for in vivo imaging will lack a particle emission, but produce a large number of photons in the 140-250 keV range, which may be readily detected by conventional gamma cameras.

The monoclonal antibodies of the invention can be used in vitro and in vivo to monitor the course of disease therapy. Such monitoring would be particularly useful for deep-tissue Staphyolococcus and Streptococcus disease, since strains of pathogens are often antibiotic resistant. This antibiotic resistance makes identification of an effective antibiotic and the appropriate dosage thereof difficult to ascertain. Thus, for example, by measuring the increase or decrease in the concentration of TSST-1 or other antigen having a peptide of the invention for which the monoclonal antibodies of the invention are specific, it would be possible to determine whether a particular therapeutic regimen aimed at ameliorating the immunopathological disease is effective.

The monoclonal antibodies can also be used immunotherapeutically for immunopathological associated disease. The term "immunotherapeutically" or "immunotherapy" as used herein in conjunction with the monoclonal antibodies of the invention denotes both prophylactic as well as therapeutic administration. Thus, the monoclonal antibodies can be administered to high-risk patients in order to lessen the likelihood and/or severity of immunopathological disease or administered to patients already evidencing active disease or infection, for example due to Staphylococcus aureus infection.

An immunotherapeutic method in accordance with this invention entails the administration of a therapeutic agent of the invention by injection or infusion prior to (prophylaxis) or following (therapy) the onset of the immunopathologi¬ cal disease. The therapeutic agent may be a monoclonal antibody of the invention which binds to a peptide of the invention. Alternatively, the therapeutic agent may be a peptide of the invention. In addition, an anti- idiotype antibody which binds to a monoclonal antibody which binds a peptide of the invention may also be used in the immunotherapeutic method of the invention. The amount of therapeutic agent required to block binding of an antigen to an immune cell receptor (e.g., MHC Class II) or to bind directly to the causative antigen to neutralize its biological effects depends on such factors as the type and severity of the infection, the size and weight of the infected subject, and the effectiveness of other concomitantly employed modes of prophylaxis or therapy.

The immunotherapeutic method of the invention includes a prophylactic method directed to those humans at risk for immunopathological diseases associated with the peptides of the invention. A peptide of the invention can be administered to a host to induce an active immune response to the peptide, for example, such that the host produces antibody to the peptide which inhibits or ameliorates the pathologic effect associated with a polypeptide having the peptide sequence of the invention. A prophylactically effective amount of a pharmaceutical composition containing a peptide or antibody of the invention- is administered to the patient in an amount which is capable of blocking the peptide antigen from binding to a immune cell receptor (e.g., MHC class II molecule) or capable of binding to the causative antigen to prevent binding to a receptor, thereby neutralizing its biological activity.

Alternatively, the peptides of the invention can be linked to a second peptide and, thereby, act as an adjuvant to induce an immune response, such as stimulation or suppression, to the second peptide. For example, peptide SEQ ID NO:1 is coupled to a Staphylococcal capsular peptide or polypeptide and used to induce a T-cell dependent B-cell proliferative response to the Staphylococcal capsular peptide or polypeptide. Those of ordinary skill in the art can readily choose which peptide of the invention to utilize in modulating the immune response to the second peptide and will know various standard techniques for linking a peptide of the invention to a second peptide, as well as the appropriate immunization protocol to achieve the desired modulatory effect on the immune system.

The dosage ranges for the administration of the monoclonal antibodies of the invention are those large enough to produce the desired effect in which the symptoms of the TSST-1 or other immunopathological disease are ameliorated or the likelihood of infection or over stimulation of the immune system decreased. The dosage should not be so large as to cause adverse side effects, such as hyperviscosity syndromes, pulmonary edema, conjestive heart failure, and the like. Generally, the dosage will vary with the age, condition, sex and extent of the disease in the patient and can be determined by one of skill in the art. The dosage can be adjusted by the individual physician in the event of any complication. Dosage can vary from about 0.1 mg/kg to about 300 mg/kg, preferably from about 0.2 mg/kg to about 200 mg/kg, most preferably from about 0.5 mg/kg to about 20 mg/kg, in one or more dose administrations daily, for one or several days.

The monoclonal antibodies of the invention can be administered parenterally by injection or by gradual infusion over time. The monoclonal antibodies of the invention can be administered intravenously, intraperitoneally, intramuscularly, subcutaneously, intracavity, or transdermally.

Preparations for parenteral administration of a peptide or an antibody of the invention include sterile aqueous or non-aqueous solutions, suspensions, and emulsions. [Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate. Aqueous carriers include water, alcoholic/aqueous solutions, emulsions or suspensions, including saline and buffered media. Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's, or fixed oils. Intravenous vehicles include fluid and nutrient replenishers, electrolyte replenishers (such as those based on Ringer's dextrose), and the like. Preservatives and other additives may also be present such as, for example, antimicrobials, anti- oxidants, chelating agents, and inert gases and the like.

When used for immunotherapy, the monoclonal antibodies of the invention may be unlabeled or labeled with a therapeutic agent. These agents can be coupled either directly or indirectly to the monoclonal antibodies of the invention. One example of indirect coupling is by use of a spacer moiety. These spacer moieties, in turn, can be either insoluble or soluble (Diener, et al., Science, 231:148, 1986) and can be selected to enable drug release from the monoclonal antibody molecule at the target site. Examples of therapeutic agents which can be coupled to the monoclonal antibodies of the invention for immunotherapy are drugs, radioisotopes, iectins, and toxins.

The drugs which can be conjugated to the monoclonal antibodies of the invention include non-proteinaceous as well as proteinaceous drugs. The terms "non-proteinaceous drugs" encompasses compounds which are classically referred to as drugs, for example, mitomycin C, daunorubicin, and vinblastine, which may typically be used when the immunopathological disease is a malignancy.

Using the monoclonal antibodies in the therapeutic method of the invention, it is possible to design therapies combining all of the characteristics described herein. For example, in a given situation, such as a malignancy, it may be desirable to administer a therapeutic agent, or agents, prior to the administra¬ tion of the monoclonal antibodies of the invention.

In addition, it is possible to use the monoclonal antibodies of the invention in combination with each other to treat an immunopathological disease. For example, a monoclonal antibody which binds to a peptide with the amino acid sequence FPSPYYSPAFTKGE or YYSPAF, which blocks binding of TSST-1 to the MHC class II molecule on human monocytes, inhibits TSST-1 T-cell mitogenicity, inhibits hematopoietic cell cytokine secretion, and neutralizes the lethal effects associated with TSST-1 , can be used in combination with a monoclonal antibody which binds the peptide STNDNIKDLLDWYS and which inhibits the T-cell mitogenicity associated with TSST-1. In a likewise manner, a monoclonal antibody which binds the peptide FPSPYYSPAFTKGE or YYSPAF, can be used in combination with a monoclonal antibody which binds the peptide FEYNTEKPPINIDEIKTIE, which inhibits the T-cell mitogenicity associated with TSST-1. The combination of more than one of the antibodies of the invention may act synergistically to ameliorate the immunopathological disease.

The peptides of the invention may also be used in combination for immunother- apy according to the method of the invention used to treat an immunopatho¬ logical disease. For example, the peptide FPSPYYSPAFTKGE, or the smaller peptide YYSPAF, which binds to the monocytic MHC class II receptor (HLA- DR), and the peptide STNDNIKDLLDWYS, which stimulates T-cell proliferation, in combination, would block (for example, by competition) a native toxin or antigen from binding to the MHC receptor and from stimulating the proliferation of T-cells, thereby substantially decreasing the likelihood of an immunopatho¬ logical disease. Combinations of any of the peptides of the invention could be used similarly to treat a subject having or at risk of having an immunopatho¬ logical disease.

The materials of the invention are ideally suited for the preparation of a kit. The kit is useful for the detection of a target molecule indicative of an immunopath¬ ological disease associated with a peptide selected from the group consisting of FPSPYYSPAFTKGE, YYSPAF, STNDNIKDLLDWYS and FEYNTEK- PPINIDEIKTIE, the kit comprising a carrier means being compartmentalized to receive in close confinement therein one or more containers such as vials, tubes, and the like, each of the container means comprising one of the separate elements to be used in the assay. For example, one of the container means may comprise a monoclonal antibody of the invention which is, or can be, detectably labelled. The kit may also have containers containing buffer(s) and/or a container comprising a reporter-means, such as a biotin-binding protein, such as avidin or streptavidin, bound to a reporter molecule, such as an enzymatic, or fluorescent label.

The invention also relates to a medicament or pharmaceutical composition comprising a peptide, polypeptide or a monoclonal antibody of the invention, the medicament being used for therapy of an immunopathological disorder associated with TSST-1 or the peptides of the invention. For example, the pharmaceutical composition comprising a peptide of SEQ ID NO:1 or a fragment thereof, such as YYSPAF, may be useful in preparing a vaccine for inducing protection against an immunopathological disorder such as toxic shock syndrome. Alternatively, a pharmaceutical composition comprising a TSST-1 polypeptide in which amino acid residue 55 is modified such that alanine is now threonine, would be useful as a vaccine for toxic shock syndrome.

The following examples are intended to illustrate but not limit the invention. While they are typical of those that might be used, other procedures known to those skilled in the art may alternatively be used. EXAMPLES

Using monoclonal and polyclonal antibodies coupled with epitope scanning technology, the present invention demonstrates that the linear peptide sequence of TSST-1 corresponding to residues 47-60 and defined by a neutralizing monoclonal antibody to TSST-1 (mAb5) may be responsible for several superantigenic activities of TSST-1. Whereas several other monoclonal antibodies were able to inhibit TSST-1 induced mitogenesis of human PBMC, only mAb5 was able to: (i) inhibit ¹²⁵-I-TSST-1 binding to human PBMC; (ii) inhibit TSST-1 induced mitogenesis of human PBMC; (iii) inhibit TSST-1 induced TNFα, IL-1 B, and IL-6 secretion from co-cultures of human monocytes and T cells; and (iv) protect against the lethal effects of TSST-1 in as in vivo subcutaneous infusion model of rabbit TSS. Furthermore, mAb5 was also capable of inhibiting SEA binding to human PBMC and blocking SEA-induced mitogenesis of human PBMC.

Using synthetic peptides, studies provided herein show that the primary amino acid sequence of TSST-1 corresponding to residues 47-60 confers both mitogenic and superantigenic effects on human PBMC. These superantigenic activities of TSST-1 appear to be mediated through the binding of residues 47- 60 (FDSPYYSPAFTKGE) to human monocytes, presumable via TSST-1 receptors within HLA-DR of the MHC class II molecules. Specifically, residues

51-56, YYSPAF, appears to be the critical domain for TSST-1 superantigen effects.

EXAMPLE 1

Materials and Methods A. Preparation of TSST-1. Highly purified TSST-1 was prepared from culture supernatants of Staphylococcus aureus (MN8), using a combination of preparative isoelectric focusing and chromatofocusing (Parsonnet, J., et al., J. Infect. Dis., 151:514-522, 1985). Toxin purity was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) (50 μg TSST- 1/lane for silver staining and 10 μg TSST-1/lane for immunoblotting with rabbit antisera raised against crude S. aureus MN8 culture supernatant). The toxin migrated as a single protein band with an apparent molecular weight of approximately 22,000. Alternative techniques for toxin purification are well known in the art. SEA was purchased from Toxin Technology, Inc. (Madison, Wl) and further purified by chromatofocusing.

B. Production of mAbs.

1. Animals. Eight-week-old female BALB/c mice (CRBL) were used for immunization. Five-month-old female BALB/c mice were used for ascites production.

2. Immunization. Mice were injected intraperitoneally (i.p.) with 0.5 ml of a 1 :1 mixture of TSST-1 (50 μg in saline) and CFA. Immunization was repeated twice at 3 week intervals, but iFA was used. Animals were bled and monitored for the presence of anti-TSST-1 antibodies by ELISA. Sera from immunized mice (or culture supernatants obtained after hybridization as described below) were added directly to plates precoated with 5 ng of TSST-1 per well. Antibody binding to TSST-1 was detected using goat anti-mouse polyvalent immunoglobulins conjugated with alkaline phosphatase (Sigma). Color development was accomplished with the substrate p-nitrophenyul phosphate (Sigma). Mice were finally boosted with 50 μg TSST-1 in saline i.p. 3 days before fusion. 3. Hybridization. The BALB/c-derived nonsecreting NS-1 myeloma cells (American Type Culture Collection, Rockville, MD) were used for hybridization by the method of Goding, J.W., (J. Immunol. Methods, 39:285, 1980), with some modifications. Splenic lymphocytes (1 x 10⁸) from the immunized mouse with the highest serum antibody titer were fused with myeloma cells (2 x 10⁷) in the presence of 50% polyethylene glycol 4000 (Merck) and 10% dimethyl sulfoxide (BDH) in RPMI 1640 medium. The cell pellet was exposed to the fusing agent for 1 min. Immediately after fusion, cells were washed and resuspended in RPMI 1640 medium containing 15% heat inactivated fetal bovine serum (FBS) (HyClone Laboratories, Inc. Utah) and hypoxanthine-aminopterin-thymidine selective medium. The cells were then plated at a density of 2.5 x 10⁵ cells per well in 96-well tissue culture plates (Falcon) containing 5 x 10⁴ splenocytes from normal mouse as feeder cells. After 10 to 14 days, culture supernatant from wells containing growing clones were screened for anti-TSST-1 antibody production by ELISA as described above. Hybridomas from ELISA positive fusion wells were cloned by limiting dilution at an average density of 1 colony per well in 96-well culture plates containing 2 x 10⁵ feeder cells. Culture supernatant from each of these isolated colonies were screened for antibody production 10-14 days later. Colonies from ELISA positive wells were recloned at least twice to ensure monoclonality. The clones were finally expanded and tested for anti-TSST-1 activity and injected i.p. with 5 x 10⁶ cells in 0.5 ml saline into mice primed with 0.5 ml IFA 3 days previously.

4. Purification of mAbs. Immunoglobulins (Ig) from ascitic fluids were purified by a combination of ammonium sulfate precipitation and MAbTrap

G (Pharmacia Fine Chemicals, Uppsala, Sweden) chromatography. EXAMPLE 2 CHARACTERIZATION OF mAbs

A. Isotyping of mAbs. Each of the mAbs was tested by immunodiffusion in 1% agarose for Ig subtype using rabbit antibodies specific for mouse Ig subclasses (Sigma) as described by Occhterlony, 0., (Handbook of Experimen¬ tal Immunology, Blackwell Scientific Publications, Oxford, f>55, 1967). A panel of six high ELISA titered antibody-secreting clones were generated and injected into IFA treated BALB/c mice to obtain ascitic fluid for further characterization. Immunoglobulins were precipitated from ascitic fluids and further purified through a MAbTrap G column. Isotyping by radial immunodiffusion using subclass-specif ic antisera yielded antibodies of the lgG1 k (mAb1 , mAb4, mAb5, and mAb6), lgG2a k (mAb2), and IgM k (mAb3) subclasses.

B. Western Blot Immunostaining. Purified Ig were assayed for their activity against TSST-1 by western blot. TSST-1 (5 μg/lane) was electrophoresed on a 14% SDS-PAGE system and blotted onto 0.45 m nitrocellulose paper (Bio- Rad). Strips of the nitrocellulose transfer blot were incubated with mAb overnight at 25° C at a concentration of 10 μg/ml. The strips were then treated with 0.1% biotinylated goat anti-mouse Ig (Cappel, Organon Teknika N.V., Belgium) for 2 hours followed by 30 min incubation with 0.1% streptavidin horseradish peroxidase conjugate (BRL, Gaithersburg). Color development was accomplished with 4-chloronaphthol substrate (BRL, Gaithersburg, MD).

All six mAbs were shown to react to the denatured TSST-1 after SDS-PAGE and electrophoretic transfer to nitrocellulose membrane (FIGURE 1). Lane: 1 (mAb1), 2 (mAb2), 3 (mAb3), 4 (mAb4), 5 (mAb5), 6 (mAb6). All mAbs bound to TSST-1 with similar intensities. The immunoblots revealed that all mAbs bound to TSST-1 as a single 22 kd protein band. C. Competitive ELISA for Epitope Typing. mAbs were compared for differential binding characteristics to TSST-1 by a competitive ELISA according to the method of Friguet, B., et al., (J. Immunol. Methods, 60:351 , 1983). The principle of the assay was based on the fact that two mAbs added together in the competitive ELISA would develop a higher absorbance than each alone if the epitopes they recognized on TSST-1 were different. Additivity was quantitatively expressed by the additivity index (A.I.) as described by Friquet, B., et al., (J. Immunol. Methods, 60:351 , 1983), using the formula:

A.I. = [2A(1 +2)/(A(1)+A(2))-1] x 100%.

where: A(1) = Absorbance of mAb#1 alone; A(2) = Absorbance of mAb#2 alone; A(1 +2) = Absorbance of mAb#2 alone; A(1 +____) - Absorbance of the combined mAb mixture.

Low A.I. values of a mAb pair close to 0% suggested that the two mAbs were recognizing the same epitope, while high A.I. values close to 100% indicated complete additivity and simultaneous binding of the two mAbs to different epitopes present on TSST-1. TSST-1 (100 μl at a concentration of 0.1 μg/ml) in 0.05 M carbonate-bicarbonate buffer, pH 9.6, was coated onto flat bottom 96-well polystyrene microtiter ELISA plates (Immulon I; Dynatech Laboratories, Inc., Alexandria, VA) overnight at 25° C. After washing three times with phosphate-buffered saline (PBS, 0.1 M, pH 7.4) containing 0.15% Tween 20 (PBS-T), mAbs were added either alone or in mixtures of pairs, at concentra¬ tions predetermined to be saturated by TSST-1 and incubated for 4 hours at 37 °C followed by 3 washes with PBS-T. Plates were then incubated with polyvalent goat anti-mouse alkaline phosphatase conjugate at 1 :350 dilution for 2 hours at 37° C. After final washing step, p-nitrophenyl phosphate substrate, 1 mg/ml in 10% diethanolamine buffer (pH 9.8), was added and incubated at 37 ^βC for 10-15 minutes. Coloration was quantitated at OD^ with a Titertek Multiscan MC spectrophotometer (Flow Laboratories).

The competitive ELISA suggested that a total of four different epitopes on TSST-1 were recognized among the six mAbs. The A.I. values of all six mAbs alone and in combinations are shown in Table 1. Results indicated that mAb2, and mAb5 recognized unique epitopes, while mAb1 and mAb3 (A.I. 3%), and mAb4 and mAb6 (A.I. 7%) recognized similar epitopes.

TABLE 1

EPITOPE TYPING BY COMPETITIVE ELISA ADDITIVE INDICES (A.I.. %) FOR THE SIX mAb PAIRS"

^a A.I. values represent the mean of at least 3 separate experiments.

^b All pairs were significantly different (p<0.005) except for mAb1/mAb3, mAb4/mAb6 and all self competing controls.

D. Relative Binding Affinity to TSST-1. The relative affinities of mAbs binding to TSST-1 were determined by ELISA as described by Lokker, et al.

(J. Immunol. 146:893, 1991). TSST-1 (100 μl at a concentration of 50 ng/ml) in 0.05 M carbonate-bicarbonate buffer, pH 9.6, was coated onto ELISA plates overnight at 25° C. After washing with PBS-T, each mAb to be tested was added (in serial dilutions varying from 50,000 ng/ml to 0.0256 ng/ml), incubated for 2 hours at 37 °C and followed by 3 washes with PBS-T. Bound mAb was detected with goat anti-mouse alkaline phosphatase conjugate and p- nitrophenyl phosphate substrate as described previously. The relative affinity of each mAb was defined as the reciprocal concentration (μg/ml) required to produce 50% maximal binding to 100 μl of TSST-1 at concentration of 50 ng/ml. The relative binding affinity of each mAb to TSST-1 (defined as the reciprocal concentration of mAb needed to produce 50% maximal binding to TSST-1) was determined by ELISA (1/2 max. OD^; Table 2). mAb3, mAb4, and mAb6 had the highest relative affinities, while mAb5 had the lowest relative affinity.

TABLE 2

CHARACTERIZATION OF SIX ANTI-TSST-1 mAbs

Relative affinity for TSST-1 (μg/ml) is defined as the reciprocal concentra¬ tion of mAb (μg/ml) needed to produce 50% maximal binding to TSST-1 (5 ng) as determined by ELISA (1/2 maximum OD^). Results are mean ± S.D. from 3 different experiments. Determined by competitive ELISA (see text). Not cross-reactive.

E. ²⁵I-TSST-1 Binding Assay. The TSST-1 mAbs were tested for their ability to inhibit the binding to ¹²⁵I-TSST-1 to human PBMC. Purified TSST-1 was iodinated by the modified chloramine T procedure (Palaszynski, E.W., et al., J. Immunol, 132:1872, 1984). Binding assay was performed according to See, R.H., et al. (Infect. Imrnun., 58(7):2392. 1990), with some modifications. Briefly, fresh human PBMC from healthy adult donors were obtained by centrifugation over Histopaque 1.077 (Sigma) of ieukopheresis packs. Cells at the interface were washed three times in Hanks balanced salt solution, and 3 x 10⁷ cells in RPMI 1640 medium containing 1% bovine serum albumin (BSA) were incubated with ^{1 5}I-TSST-1 (3 nM) in the absence or presence of either mAbs (various concentrations) or unlabelled TSST-1 (300 nM) in final volumes of 0.5 ml for 2 hours at 4°C. Cells were then washed three times with ice-cold RPMI 1640 medium in order to remove unbound ¹²⁵I-TSST-1. Bound radioactivity was measured in a Searle 1185 gamma counter. All samples were done in triplicate and all data were expressed in terms of specific ^{1 5}I-TSST-1 binding determined by subtracting the nonspecific binding from the total binding. Their relative inhibitory activities were expressed as the concentration of mAb required to give 50% inhibition in specific binding of ¹²⁵I-TSST-1 (3 nM) to human PBMC (IC50).

Serial dilutions of the six mAbs were tested for their ability to inhibit the binding of ¹²⁵I-TSST-1 to human PBMC. The results of a representative experiment using all six mAbs for a single PBMC donor are shown in FIGURE 2a (at four different concentrations of varying from 1.2 nM to 1200 nM). The mAbs were incubated with 3 nM ¹²⁵I-TSST-1 for 2 hours before adding to human PBMC of a single donor. 100% is the maximum inhibition and 0% is no inhibition. The asterisks above the bars indicate the lowest concentration of the mAbs required to inhibit TSST-1 binding significantly. Higher concentrations were also significant. Results (mean ± S.D. from triplicate samples) show that only mAb2. and mAb5 inhibited ¹²⁵I-TSST-1 binding to the cells significantly and in a dose-dependent manner.

Among the six mAbs, only two mAbs (mAb2 and mAb5) were capable of inhibiting ¹²⁵I-TSST-1 binding to the cells significantly (p<0.01 at mAb2 concentrations of 12 nM or higher, and p<0.001 at mAb5 concentrations of 1.2 nM or higher) and in a dose-dependent manner. Interestingly, mAb3 was also able to inhibit ¹²⁵I-TSST-1 binding to the cells significantly at concentrations of 12 nM or higher (p<0.01). However, there was no dose-response relationship at higher concentrations of mAb3. The concentration of each mAb required to give 50% inhibition (IC50) in ²⁵I-TSST-1 binding (mean ± S.D.) to human PBMC from three different healthy donor is shown in Table 3. Among the two mAbs which could inhibit binding, mAb5 was the most potent, requiring the least amount (19 ± 18 nM) to inhibit 50% of binding by 3 nM of ¹²⁵I-TSST-1 to human PBMC.

In addition, mAb5 inhibition of ¹²⁵I-SEA binding to human PBMC was examined using the methods described above for TSST-1. FIGURE 2b shows that mAb5 inhibited ^{1 5}I-SEA binding to the cells in a dose-dependent manner and with an IC_∞ of 29.49 μM.

F. Mitogenicity Assay. The mAbs were tested for their ability to inhibit the mitogenic activity of TSST-1 on human PBMC. Mitogenicity assays were performed as previously described (Kum, W.W.S., et al., Improved Purification of Staphylococcal Toxic Shock Syndrome Toxin-1 , in press, 1993). Fresh human PBMC [3 x 10⁵ cells in 100 μl of RPM1 1640 medium supplemented with 10% FBS, 2 mM L-glutamine (Gibco), and 20 μg/ml polymyxin B sulfate (Sigma)] were cultured in 96-well round-bottom tissue culture plates (Falcon), and incubated with an equal volume of TSST-1 (0.45 nM) with or without various concentrations of mAb, at 37 °C, 5% C0₂ for 48 hours. Cells were then pulsed with 1 μCi of [³H]-thymidine (5 Ci per mole; Amersham, Arlington Heights, Ont.) and harvested 18 hours later onto glass-fiber filter paper using an automatic harvester (Skatron, Norway). All samples were run in triplicates and counted in a liquid scintillation counter (Beckman LS1800). Their relative inhibiting activities were expressed as the concentration of mAb required to give 50% inhibition of mitogenic activity by cells induced with 0.45 nM TSST-1 (IC50).

All six mAbs were examined for their ability to inhibit TSST-1 induced T cell proliferation from human PBMC. The results of a representative experiment, using all six mAbs for a single PBMC donor, are shown in FIGURE 3a. TSST-1 mAbs were incubated with TSST-1 (0.45 nM) for 2 hours before adding to human PBMC of a single donor. 100% is the maximum inhibition and 0% is no inhibition. The asterisks above the bars indicate the lowest concentration of the mAbs required to inhibit TSST-1 induced mitogenesis significantly. Higher concentrations were also significant. Results (mean ± S.D. from triplicate samples) show that only mAb1 , mAb2, and mAb5 inhibited the mitogenic response of TSST-1 significantly and in a dose-dependent manner, and mAb5 was the most potent.

As expected, the mAb to HLA-DR, L243, inhibited TSST-1 induced mitogenesis significantly (p<0.05 at concentrations of 1 nM or higher) and in a dose dependent manner. Of all the TSST-1 mAbs tested, only three mAbs (mAb1 , mAb2, and mAb5) significantly inhibited the mitogenic response of TSST-1 (p<0.05 at mAb1 concentrations of 10 nM or higher, p<0.01 at mAb2 concen¬ trations of 1 nM or higher, and p<0.01 at mAb5 concentrations of 0.1 nM or higher) and in a dose-dependent manner. The concentration of each mAb (mean ± S.D.) required to give 50% inhibition (IC50) in mitogenic activity to human PBMC from four different healthy donors is shown in Table 3. Among the three mAbs capable of inhibiting TSST-1 induced mitogenicity, mAb5 was again the most potent, requiring the least amount (1.19 ± 0.6 nM) to accom¬ plish 50% inhibition in mitogenesis induced by 0.45 nM of TSST-1.

In addition, the effect of SEA induced mitogenesis of human PBMC was examined as described above for TSST-1. The results are shown in FIGURE 3b. SEA (0.45 nM) was incubated with human PBMC in the presence or absence of various concentrations of mAb5 at 37 ^βC in 5% C0₂ for 48 hours. Cells were pulsed with ³H-thymidine and harvested 18 hours later. Maximum inhibition is 100% and minimum inhibition is 0%. FIGURE 3b shows that mAb5 inhibited the mitogenic response of SEA with an IC^ of 345nM. TABLE 3

EFFECT OF DIFFERENT mAbs ON VARIOUS BIOLOGICAL ACTIVITIES OF TSST-1

IC_gQ, concentration of mAb (nM) required to give 50% inhibition in binding of 1 '2"5l.-TSST-1 (3 nM) to human PBMC. Results are mean ± S.D. from 3 different donors.

IC_gn, concentration of mAb (nM) required to give 50% inhibition in mitogenic activity of TSST-1 (0.45 nM) in human PBMC. Results are mean ± S.D. from 4 different donors.

IC_go, concentration of mAb (nM) required to give 50% inhibition in cytokine secretion induced by TSST-1 (0.45 nM) in human PBMC. Results are mean ± S.D. from 6 different donors.

No inhibitory activity detected.

L243 was shown previously to inhibit binding of ¹²⁵I-TSST-1 to human monocytes in a dose dependent manner (See, et al., Can. J. Microbiol. 38:937, 1992).

G. Induction of TNFα, IL-1/3, and IL-6. The mAbs were tested for their ability to inhibit the induction of cytokines by TSST-1 in co-cultures of human monocytes and T cells (1 :1). Human PBMC and fractionated human monocytes or T cells were prepared according to See, R.H., et al., Infect. Immun., 60:(8.:3456. 1992; See, R.H., et al., Infect. Immun., 60(7^:2612. 1992. Briefly, fresh human PBMC were prepared as described above. Mononuclear cells were first separated into T and non-T cell populations by rosetting with sheep red blood cells. Monocytes were then separated from B lymphocytes by density centrifugation over Percoll (Pharmacia Fine Chemicals, Dorval, Quebec). Purity of the monocyte preparations was > 90% as assessed by non-specific esterase staining. For the isolation of purified human T lympho- cytes, E-rosetted cells were first treated with ammonium chloride to lyse sheep red blood cells, washed three times, and subjected to antibody directed complement lysis to remove contaminating monocytes and B cells by using an antibody to the HLA-DR antigen (L243), and antibody to the monocyte-specific CD11 b antigen (OKM1), and pooled rabbit complement. Purified human T cells were >98% CD2⁺ and <2% HLA-DR⁺ as determined by flow cytometric analysis. For cytokine induction studies, 1 x 10⁶ monocytes and 1 x 10⁶ T cells were cultured in complete RPMI 1640 medium supplemented with 10% FBS, 2 mM L-glutamine, and 20 μg/ml polymyxin B sulfate, in 24-well tissue culture plates (Falcon) with TSST-1 (0.45 nM) in the presence or absence of various concentrations of the different mAbs, at 37°C in 5% C0₂. After 24 hours, culture supernatants were collected, microfuged at 800 x g for 5 min, and frozen at -70° C until analysis. The presence of TNFα, \ - .β, or IL-6 in stimulated culture supernatants was assayed by ELISA (See, R.H., et al., Infect. Immun., 60:.8.:3456. 1992; See, R.H., et al., Infect. Immun., 60(Z1:2612, 1992). Briefly, ELISA plates were coated overnight with 2 μg/ml goat anti-human TNFα,

\ - _β, or IL-6 antibodies (R & D Systems, Minneapolis, MN) in carbonate- bicarbonate buffer, pH 9.6. Test samples or human recombinant TNFα, \\-- _β_. or IL-6 standards (R & D Systems) in PBS with 3% BSA were added in triplicate, and incubated at 37 °C for 90 min. The plates were washed and incubated with the appropriate biotinylated secondary goat antibodies at 37 °C for 90 min. After washing the incubation with streptavidin alkaline phosphatase (Gibco/BRL) at 37° C for 20 min, an ELISA amplification system (Gibco/BRL) was then used to increase the sensitivity of the assay. Coloration was quantitated at OD₄₉₅. The relative inhibiting activity of each TSST-1 mAb was expressed as the concentration of mAb required to give 50% inhibition of TNFα, IL-1 9, or IL-6 secretion in cells induced with 0.45 nM TSST-1 (IC50).

The six mAbs were studied for their ability to inhibit TSST-1 induced secretion of TNFα, IL.-1 3, and IL-6 from co-cultures of human monocytes and T cells (1 :1). The results of a representative experiment, using all six mAbs for a single PBMC donor, are shown in FIGURE 4. mAbs were incubated with TSST-1 (0.45 nM) for 2 hours before adding to co-cultures of human monocytes and T cells (1 :1) from a single donor. Supernatants were harvested and assayed by ELISA for the presence of TNFα (FIGURE 4a), IL-1 3 (FIGURE 4b), and IL-6 (FIGURE 4c). 100% is the maximum inhibition and 0% is no inhibition. The asterisks above the bars indicate the lowest concentration of the mAbs required to inhibit TSST-1 induced cytokines secretion significantly. Higher concentrations were also significant. Results (means ± S.D. from triplicate samples) show that only mAb2, and mAb5 were able to inhibit secretion of all three cytokines in a dose-dependent manner. mAb5 was 80- ^• to 600-fold more potent than mAb2.

Only two mAbs (mAb2, and mAbδ) significantly inhibited TSST-1 induced secretion of TNFα (p<0.01 at mAb2 concentrations of 45 nM or higher, and p<0.01 at mAb5 concentrations of 0.45 nM or higher), I -1 3 (p<0.01 at mAb2 concentrations of 4.5 nM or higher, and p<0.001 mAb5 concentrations of 4.5 nM or higher), and IL-6 (p<0.01 at mAb2 concentrations of 45 nM or higher, and p<0.001 at mAb5 concentrations of 4.5 nM or higher) from human PBMC and in a dose-dependent manner (FIGURE 4a, 4b, and 4c, respectively). The concentration of each mAb (mean ± S.D.) required to give 50% inhibition (IC50) in cytokine secretion by human PBMC from six different healthy donors is shown in Table 3. Among these, mAbδ was again the most potent in inhibiting these activities. As described previously (See, R.H., et al., Infect. Immun., 60(71:2612, 1992), the control mAb, L243, was unable to inhibit the effect of TSST-1 on cytokine induction from human PBMC.

TABLE 4

PROTECTION FROM TSST-1 INDUCED LETHALITY BY VARIOUS mAbs IN THE SUBCUTANEOUS INFUSION MODEL OF RABBIT TSS

mAb DIED SURVIVED P^a

Untreated 7 3 mAb1 10 0 1.00 mAb2 1 9 0.02 mAb3 6 4 1.00 mAb4 8 2 1.00 mAb5 0 10 0.003 mAb6 6 4 1.00 p value for difference in mortality compared to rabbits receiving TSST-1 alone.

H. Animal Protection Assay. The subcutaneous infusion model of rabbit TSS- like illness described by Parsonnet, et al., (Infect. Immun., 55:1070, 1987), was used to determine the effect of the mAbs on the lethality of TSST-1 in vivo. Briefly, TSST-1 was administered to male 18-20 week old NZW rabbits as a constant infusion over a period of 7 days via subcutaneously implanted miniosmotic pumps (Alza Corp., Palo Alto, CA). TSST-1 was infused at a rate of 0.6 μg/kg/h, a concentration predetermined to cause 70% lethality, either alone or in the presence of various mAbs (5 x molar excess). The animals were observed twice daily and their weights and rectal temperatures were recorded.

All six mAbs were tested for their ability to protect against the lethal effects of TSST-1 in the subcutaneous infusion rabbit model. TSST-1 , at a dose predetermined to cause 70% lethality, was administered either alone or in the presence of the different mAbs through subcutaneously implanted miniosmotic pumps. Ten animals per group were studied. Death after 7 days was the end point of this protection assay. Seven out of ten rabbits died in the untreated group, with a mean time until death of 3 days.

Mortality was lowest among the animals treated with mAb2 (1 of 10, p=0.02 vs untreated controls), and with mAb5 (0 of 10, p= 0.003 vs untreated controls) (Table 4). All the other mAbs were ineffective in this protection assay.

I. Statistical Analysis. The Student's t-test (2-tailed) was used to compare the A.I. values of pairs and self competing controls in the epitope typing by competitive ELISA, as well as to compare the differences in TSST-1 induced in vitro biologic activities, including ¹²⁵I-TSST-1 binding, mitogenicity, and induction of TNFα, IL-1_/3, and IL-6, in the presence or absence of the various mAbs. Differences were considered significant when p values of <0.005 were obtained. As for the animal protection assay, the differences in lethality between the treated groups (receiving TSST-1 in the presence of various mAbs) and the untreated group (receiving TSST-1 without mAb) were compared using the Fisher's exact test (two-tailed). Differences were considered significant when p values of <0.05 were obtained.

EXAMPLE 3 LOCALIZATION OF TSST-1 DOMAINS BY EPITOPE MAPPING

Polyclonal Rabbit TSST-1 Antisera. New Zealand White rabbits (purchased from R and R Rabbitry, Stanwood, WA) were immunized with a 1 :1 mixture containing 0.5 mg TSST-1 emulsified in complete Freund's adjuvant (CFA, Sigma Chemical Co., St. Louis, MO), and administered both intramusculary and subcutaneously into multiple sites for the initial inoculation. Subsequent boosters were prepared in similar manner except that TSST-1 was emulsified in incomplete Freund's adjuvant (IFA, 1 :1) and that three injections at 2 week intervals were given. The animals were bled 2 weeks after the final booster injection.

Monoclonal Antibodies. mAbs were prepared against TSST-1 according to procedures described in Example 1. Briefly, BALB/c mice (CRBL) were immunized intraperitoneally with 50 μg of TSST-1 emulsified in CFA (1 :1). Immunization was repeated twice at 3 week intervals, but IFA was used for these boosters. Animals were bled and monitored for the presence of anti- TSST-1 antibodies by ELISA. For hybridoma production, splenocytes (1 x 10⁸) from the immunized mouse with the highest serum antibody titer were fused with 2 x 10⁷ BALB/c-derived nonsecreting NS-1 myeloma cells (ATCC) in the presence of 50% polyethylene glycol 4000 (Merck) and 10% dimethyl sulfoxide (BDH) in serum free RPMI 1640 medium. Immediately after fusion, cells were washed and resuspended in RPMI medium containing 15% heat inactivated fetal bovine serum (HyClone Laboratories, Inc., Utah) and hypoxanthine- aminopterin-thymidine selective medium. The cells were then plated at a density of 2.5 x 10⁵ cells per well in 96-well tissue culture plates (Falcon) containing 5 x 10⁴ splenocytes from normal mouse as feeder cells. After 10 to 14 days, culture supernatants were screened for anti-TSST-1 antibody production by ELISA. Positive clones were subcloned twice by limiting dilution and expanded in IFA primed BALB/c mice. Immunoglobulins from ascitic fluids were purified by a combination of ammonium sulfate precipitation and MAbTrap G chromatography (Pharmacia Fine Chemicals, Uppsala, Sweden).

Synthesis of Peptides. Peptides were synthesized utilizing the Epitope Scanning Kit supplied by Cambridge Research Biochemicals Inc. (CRB, Wilmington, Delaware). The general method of Geysen, H.M., et al., (Proc. Natl. Acad. Sci., U.S.A.,_81:3998, 1984; Geysen, H.M., et al., J. Immunol Methods, 102:259, 1987), was followed, based on the principles of the solid- phase peptide synthesis of Merrifield, R.B., J. Am. Chem. Soc. §5:2149, 1963, but using the known N luorenylmethyloxycarbonyl (Fmoc) protecting group strategy. One hundred and eighty-five overlapping 10-mer peptides, moving one amino acid at a time through the entire linear sequence of the 22 kD TSST-1 protein (Blomster-Hautamaa, D.A., et al., J. Immunol., 137(11.:3572. 1986), were synthesized in duplicate on prederivatized polyethylene pins, using Fmoc-amino acid active esters as described in the manufacturer's instruction manual (CRB). The peptides remained coupled to polyethylene pins after acetylation of terminal amino groups and side chain deprotection. Binding to polyclonal and various mAbs against TSST-1 was assayed by ELISA and quantitated by absorption at 405 nm.

Antibody Binding Assays. Binding of synthetic peptides to antibodies was assayed by ELISA. The peptide-pins were quenched with a solution consisting of 1% ovalbumin (Sigma), 1% bovine serum albumin (Sigma) in phosphate- buffered saline (PBS), and 0.1% Tween 20 (supercocktail) at 25°C for 1 hour. The peptide-pins, arranged in a 96-well format, were placed in microtiter plates containing 0.175 ml 62.5 nM rabbit polyclonal or various murine mAbs against TSST-1 in supercocktail and incubated overnight at 4^βC. The mAb to HLA-DR (L243), and normal rabbit serum were used as control. After several washes in PBS containing 0.05% Tween 20, the peptide-pins were placed in microtiter plates containing the appropriate secondary antibody alkaline phosphatase conjugate (goat anti-rabbit alkaline phosphatase conjugate [Bethesda Research Laboratories (BRL), Life Technologies, Inc., Gaithersburg, MD] at a dilution of 1 :4,000 or goat anti-mouse alkaline phosphatase conjugate (Sigma) at a dilution of 1 :350). Following several washes, antibody binding was detected by developing with p-nitrophenyl phosphate substrate (Sigma, 1 mg/ml in 10% diethanolamine buffer, pH 9.8) in microtiter plates, and reading the absorbance at 405 nm in a microplate ELISA reader (Titertek Multiskan, Flow Laboratories, Paris, France). Epitope Peptide Scanning. All of the 185 possible overlapping decapeptides, moving one amino acid at a time through the entire 194 linear amino acid sequence of the TSST-1 molecule, were synthesized in duplicate on solid supports. The amino acid sequence had been deduced from the nucleotide sequence of the TSST-1 gene (Blomster-Hautamaa. D.A., et al., J. Biol. Chem., 261 (33. :15783. 1986). The binding of the synthesized peptides to rabbit polyclonal antibodies and murine mAbs against TSST-1 was tested by ELISA. The reactive peptides were defined as those showing OD peaks in the scan which clearly stood out above the background.

The antigenic profile of the synthetic peptides using a rabbit polyclonal antibody against TSST-1 is shown in FIGURE 5. Results are shown as vertical lines proportional to the extinction obtained in the antibody-binding ELISA assay, plotted above the number giving the location of the 194 amino acid sequence of the TSST-1 molecule. Peptides with positive reactions were located in five regions corresponding to residues 2-17, 38-51 , 54-69, 159-175, and 177-191 (FIGURE 5 and 6). All regions bound equally well except for the antigenic peptide 38-51 which bound weakly to the antibodies.

MAb2 and mAb5, the only mAbs demonstrated to inhibit binding of TSST-1 to human PBMC, to inhibit TSST-1 induced mitogenicity and block cytokine secretion, and to protect against the lethal effects of TSST-1 in a subcutaneous infusion model of rabbit TSS, were shown to recognize similar or overlapping peptides corresponding to TSST-1 residues 49-59 (SPYYSPAFTKG) (FIGURE 6 and 7b) and 47-60 (FPSPYYSPAFTKGE) (FIGURE 6 and 7e), respectively. FIGURE 6 shows mapping of the amino acid sequence of TSST-1 with 5 antigenic domains defined by rabbit polyclonal TSST-1 antibody ---. and 5 domains defined by mAb1-mAb6 = = = (mAb3 did not bind to any of the overlapping TSST-1 peptides). FIGURE 7 shows epitope scanning profiles of TSST-1 using the six anti-TSST-1 mAbs: 7a, mAb1 ; 7b, mAb2; 7c, mAb3; 7d, mAb4; 7e, mAb5; 7f, mAb6.

Mab1 , which was shown to inhibit TSST-1 induced mitogenicity but not TSST-1 binding to human PBMC or cytokine secretion, recognized a 14 amino acid amino-terminal epitope, STNDNIKDLLDWYS, corresponding to residues 1-14 of the TSST-1 molecule (FIGURE 6 and 7).

Mab3, which was shown to have modest inhibitory activity for TSST-1 binding to human PBMC but not TSST-1 induced mitogenicity (Kum, W.W.S., et al., 1993), did not bind to any of the linear amino acid sequences of the TSST-1 molecule (FIGURE 6 and 7c).

Both mAb4 and mAb6, which were shown to have no effect on any of the TSST-1 induced responses in vitro and in vivo, recognized similar peptide close to the carboxy-terminus corresponding to TSST-1 residues 174-190 (YNTEKPPI- NIDEIKTIE) (FIGURE 2 and 3d) and 172-190 (FEYNTEKPPINIDEIKTIE) (FIGURE 6 and 7f), respectively.

As expected, neither L243 nor normal rabbit serum bound to any of the linear amino acid sequence of the TSST-1 molecule.

A panel of six mAbs and epitope scanning of overlapping peptides synthesized on solid supports was used to localize precisely the superantigenic and lethal domains on the linear sequence of the TSST-1 molecule. The 14 amino acid linear sequence, defined by mAbδ and encompassing residues 47-60 (FPSPYYSPAFTKGE), is probably the critical domain for both the superantige¬ nic and lethal effects of the TSST-1 molecule. In Examples 1 and 2, using competitive ELISA for epitope typing, mAb2 and mAbδ were shown to recognize unique epitopes. However, mAb2 and mAb5 were also shown to be the only mAbs within the panel to inhibit TSST-1 binding to human PBMC, neutralize TSST-1 induced mitogenicity, block TSST-1 induced TNFα, \L- _β, and IL-6 secretion, and protect against the lethal effects of TSST-1 in the subcuta¬ neous infusion model of rabbit TSS. However, mAbδ was 20- to 600-fold more active than mAb2 in inhibiting these biologic activities of TSST-1 in vitro. mAb2 and mAbδ were shown to recognize similar and overlapping linear sequences within TSST-1 (residues 49-δ9 and 47-60, respectively). Thus, it is unlikely that there are two distinct binding sites or lethal epitopes on the TSST-1 molecule; rather, mAb2 and mAbδ may be recognizing similar linear epitopes which fold differently in their three-dimensional conformation. Since mAbδ is the most potent mAb in neutralizing the lethal and superantigenic effects of TSST-1 in vitro and in vivo, we feel that the domain defined by mAbδ is likely the more critical epitope for these biologic activities of TSST-1.

mAbδ provided indirect evidence that TSST-1 residues (47-60) may be the critical domain in the pathogenesis of TSS. This hypothesis is further strengthened by the finding of sequence homology between TSST-1 , staphylococcal enterotoxin (SE) A and SEE in 7 residues towards the carboxyl end of this TSST-1 (47-60) peptide (FIGURE 8), suggesting that this region may define the overlapping epitopes of the HLA-DR receptor on human monocytes to both TSST-1 and SEA (See, R.H., et al., Clin. Res. 38:11δA., 1990; See,

R.H., et al., Can. J. Microbiol., 38:937, 1992). FIGURE 8 shows the amino acid sequence homology between TSST-1 and staphylococcal enterotoxins as identified by using the computer search program, MACAW.

The epitope scanning studies clearly indicate that mAb4 and mAbδ recognize the same linear sequence of TSST-1 near the carboxy-terminus of the TSST-1 molecule (residues 172-190). This is consistent with findings by competitive ELISA that these two mAbs recognize identical epitopes. mAb1 , however, binds to the amino-terminal region of the TSST-1 molecule (residues 1-14). Since none of these mAbs either neutralized TSST-1 induced cytokine secretion from human PBMC, or protected from lethality in rabbits, neither the amino-nor carboxy-terminal epitopes of the TSST-1 molecule appear important by themselves for the superantigenic or lethal properties of TSST-1.

Surprisingly, mAb3 did not bind to any of the linear peptide sequences of the TSST-1 molecule, even though this mAb bound to denatured TSST-1 in western blot immunostaining. This apparent disparity could be due to the fact that mAb3 is an IgM immunoglobulin subtype which binds less efficiently to linear peptide epitopes than to conformational determinants.

EXAMPLE 4

DETERMINATION OF MHC CLASS II BINDING DOMAIN OF STAPHYLOCOCCAL TSST-1

A. Synthesis of Peptides. Peptides with amino acid sequences corresponding to residues 47-60 or T(47-60), residues 47-64 or T(47-64), and residues 144- 1δ3 or T(144-1δ3) of the primary structure of TSST-1 were synthesized and purified at the University of Victoria Protein Microchemistry Center, Victoria, Canada. T(144-1δ3) was selected as an irrelevant peptide and negative control based on hydrophiiicity and accessibility and by flexibility studies or the TSST-1 molecule, and based on the previous finding that this peptide did not inhibit ¹²⁵I-TSST-1 binding to human PBMC even when tested at up to 10,000-fold molar excess (R.H., et al., Infect. Immun., δ8:2392-2396, 1990). Briefly, T(47- 60) with the sequence FPSPYYSPAFTKGE (SEQ ID NO:1), T(47-64) with the sequence FPSPYYSPAFTKGEKVDL (SEQ ID NO:11), and T(144-1δ3) with the sequence YRSSDKTCCY (SEQ ID NO:13), were synthesized on a Model 130A Applied Biosystems Peptide Synthesizer using the FastMoc Chemistry (HBTU/HOBt Activation) method. Applied Biosystems 0.2δ mmol FastMoc cycles were used during the synthesis. The peptides were purified on a Beckman Liquid Chromatograph Model 332 with an Applied Biosystems Brownlee C-18 column (Aquapore ODS 20μ, 2δ0 x 10 mm).

B. ¹²⁵I-TSST-1 and ¹²⁵I-SEA Competitive Binding Assays. The synthetic peptides T(47-60), T(47-64), and T(144-1 3) were tested for their ability to inhibit the binding of ¹²⁵I-TSST-1 and of ¹²⁵I-SEA to human monocytes. Purified TSST-1 and SEA were iodinated by the modified chloramine T procedure (Palaszynski, E.W., et al., J. Immunol. 132:1872-1878, 1984). Binding assays were performed according to See, et al., supra. Briefly, fresh human PBMC from healthy adult donors were obtained by centrifugation of plateletphoresis buffy coats over Histopaque 1.077 (Sigma Chemical Co., St. Louis, MO). Cells at the interface were washed three times in Hank's balanced salt solution and additionally separated into T cell and non-T-cell subpopulations by rosetting with sheep red blood cells. Monocytes were then separated from B lympho¬ cytes by density centrifugation over Percoll (Pharmacia fine Chemicals, Dorval, Quebec) to give a final specific gravity of 1.062 g per mL One mL of RPMI 1640 with 10% heat-inactivated fetal bovine serum (FBS, HyClone Laboratories, Inc., Logan, Utah) was gently layered on top of each suspension. The gradient was then centrifuged at 8δ0 x g for 1δ minutes. The monocyte-containing interface was removed and washed three times in Hank's balanced salt solution. Purity of the monocyte preparation was over 90% as assessed by non-specific esterase staining of preparations (Yam, et al., Am. J. Clin. Pathol., δδ:283-290, 1971). Trypan blue exclusion shows >9δ% viability of cells. Purified monocytes (3 x 10⁷ cells) in phosphate-buffered saline (PBS, pH 7.4) containing 1% bovine serum albumin (BSA) were incubated at 4°C for 2 hours with ¹²⁵I-TSST-1 or ¹²⁵I-SEA (3 nM) in final volumes of O.δ mL in the absence or presence of different concentrations of either peptide, or unlabeled TSST-1 or SEA (300 nM). Cells were then washed three times with ice-cold PBS in order to remove unbound ¹²⁵I-TSST-1 or ¹²⁵I-SEA. Bound radioactivity was measured in a Searle 118δ gamma counter. All experiments were performed in triplicate. Nonspecific binding was determined by adding a 100-fold or greater molar excess of unlabeled TSST-1 or SEA, and the specific ¹²⁵I-TSST-1 or ¹²⁵I-SEA binding was determined by subtracting the nonspecific binding from the total binding (in the absence or unlabeled TSST-1 or SEΞA). The relative inhibitory activity was expressed as the concentration of either peptide required to give δ0% inhibition (IC^_j) in ¹²⁵I-TSST-1 or ¹²⁵I-SEA (3nM) binding to human monocytes.

C. Mitogenicity Assay. T(47-60), T(47-64), and T(144-1 δ3) were tested for their ability to: (i) stimulate T cell proliferation; and (ii) inhibit the mitogenic activity of TSST-1 or SEA on human PBMC. Mitogenicity assays were performed as previously described (EΞxample 2F; Kum, W.W.S., et al., Clin. Res., 41:44A, 1993). Briefly, human PBMC (3 x 10⁵ cells) in 100 μL of RPMI 1640 medium supplemented with 10% heat-inactivated FBS, 2 mM L-glutamine (Gibco) and 20μg/mL polymyxin B sulfate (Sigma) were cultured in 96-well round-bottom tissue culture plates (Falcon) and incubated at 37° C in δ% C0₂ for 3 days with^* an equal volume of either peptide (various concentrations) in the presence or absence of TSST-1 or SEA (0.1 pM). AT 48 hours, cells were pulsed with 1 μCi of [³H]-thymidine (δ Ci per mmole; Amersham, Arlington Heights, Ont.) and harvested 18 hours later onto glass-fiber filter paper using an automatic harvester (Skatron, Norway). All experiments were performed in triplicate and samples were counted in a liquid scintillation counter (Beckman LS1800). The relative inhibitory activity was expressed as the concentration of peptide required to give 50% inhibition (IC_go) of mitogenic activity by cells induce with 0.1 pM TSST-1 or SEA.

D. Cytokine Assay for TNFα. T(47-60) and T(144-153) were tested for their ability to: (i) stimulate the release of TNFα; and (ii) inhibit the TSST-1 induced TNFα secretion from co-cultures of human monocytes and T cells (1 :1). Induction and release of TNFα from the cells into culture supernatants were performed as previously described (Example 2G; Kum, supra, See, supra., and See, et al., Infect. Immun., 60:2612-2618, 1992). Briefly, human monocytes were prepared as described above. For the isolation of purified human T lymphocytes, E-rosetted cells obtained as described above were first treated with ammonium chloride to lyse sheep red blood cells, washed three times, and subjected to antibody directed complement lysis to remove contaminating monocytes and B cells by using an antibody to the HLA-DR antigen (L243), an antibody to the monocyte-specific CD11b antigen (OKM1), and pooled rabbit complement. Purified human T cells were >98% CD2+ and <2% HLA-DR+ as determined by flow cytometric analysis. For TNFα induction studies, approximately 5 x 10⁵ monocytes were mixed with 5 x 10⁵ T cells and cultured at 37°C in δ% C0₂ in complete RPMI 1640 medium supplemented with 10% heat-inactivated FBS, 2 mM L-glutamine and 20 μg/mL polymyxin B sulfate (Sigma) in 24-well tissue culture plates (Falcon) together with different concentrations of peptide, in the presence or absence of TSST1 (4.δ pM). After 24 hours, culture supernatants were collected, microfuged at 800 x g for δ minutes, and frozen at -70° C until analysis. The presence of TNFα in culture supernatants was assayed by ELISA as previously described (R.H., and A.W. Chow, Immun., 60:34δ6-34δ9, 1992; R.H., and A.W. Chow, et al., Clin. Res., 38:11δA, 1990). Briefly, fiat-bottom 96-well microtiter plates (Immulon I, Dynatech Laboratories, Inc., Alexandria, Va.) were coated overnight with 2 μg/ml goat anti-human TNFα (R & D Systems, Minneapolis, MN) in carbonate buffer, pH 9.6. Test samples or human recombinant TNFα standards (R & D Systems) in PBS with 3% BSA were added in triplicate and incubated at 37 °C for 90 minutes. The plates were washed and incubated with biotinylated secondary goat anti-human TNFα at 37° C for 90 minutes. After washing and incubation with streptavidin alkaline phosphatase at 37°C for 20 minutes, an ELISA amplification system (Gibo/BRL) was then used to increase the sensitivity of the assay (R.H. and A.W. Chow, et al., Infect. Immun., 60:2612-2618, 1992). Coloration was quantitated at OD₄₉₅ with a Titertek Multiscan MC spectropho- tometer (Flow Laboratories). The relative inhibitory activity was expressed as the concentration of either peptide required to give 50% inhibition (IC_go) of TNFα production by cells induced with 4.δ pM TSST-1.

TSST-1 was purified to homogeneity as demonstrated by one single protein band (molecular size, 22 kD) on silver staining after SDS-PAGE following 10 μg protein loading. Commercial SEA was further purified to homogeneity by chromatofocusing as demonstrated by one single protein band (molecular size, 30 kD) on silver staining after SDS-PAGE following 10 μg protein loading. Purity of T(47-60) and T(144-1δ3) were verified by reverse phase HPLC analysis indicating one single major peak. Amino acid analysis of these peptides revealed that the amino acid composition conformed with the theoretical values.

EXAMPLE 5

COMPETITIVE INHIBITION OF ^t25l-TSST-1 AND ^{t 5}l-SEA

BINDING TO HUMAN MONOCYTES

T (47-60) inhibited ¹²⁵I-TSST-1 binding to human monocytes in a dose dependent manner (FIGURE 9a). The concentration of T(47-60) required to give δ0% inhibition in ¹²⁵I-TSST-1 binding to the cells was 1.6 mM. The irrelevant peptide, T(144-1δ3), was unable to inhibit the binding of ^{1 5}I-TSST-1 to cells even at a concentration of δ mM. Similarly, T(47-64) but not T(144-1δ3) inhibited ¹²⁵I-SEA binding to the cells was 2.1 mM (FIGURE 9b). The irrelevant peptide, T(144-1δ3), was unable to inhibit the binding of ¹²⁵I-SEA to the cells, even at a concentration of δ mM. EXAMPLE 6

COMPETITIVE INHIBITION OF TSST-1 AND SEA

INDUCED MITOGENICITY OF HUMAN PBMC

Neither T(47-60) nor T(144-1δ3) by themselves stimulated mitogenesis of human PBMC even at a concentration of 10 mM (FIGURE 10). However, only T(47-60) but not T(144-1δ3) inhibited TSST-1 induced mitogenesis of human PBMC and in a dose-dependent manner (FIGURE 11a). The concentration of T(47-60) required to give δ0% inhibition in TSST-1 induced mitogenesis was 1.4 mM. The irrelevant peptide, T(144-1δ3), was unable to inhibit TSST-1 induced mitogenesis even at a concentration of δ mM. Similarly, only T(47-64) but not T(144-1δ3) inhibited SEA induced mitogenesis of human PBMC and in a dose- dependent manner (FIGURE 11b). The concentration of T(47-60) required to give δ0% inhibition in SEA induced mitogenesis was 1.7 mM. The irrelevant peptide, T(144-153), was unable to inhibit SEA induced mitogenesis even at a concentration of 5 mM.

EXAMPLE 7

COMPETITIVE INHIBITION OF TSST-1 INDUCED

TNFα SECRETION FROM HUMAN PBMC

Neither T(47-60) nor T(144-1δ3) by themselves induced TNFα secretion for co- cultures of human monocytes and T cells (1:1) even at a concentration of 10 mM (FIGURE 12). However, only T(47-60) but not T(144-1δ3) inhibited TSST-1 induced TNFα secretion from the cells and in a dose-dependent manner (FIGURE 13). The concentration of T(47-60) required to give δ0% inhibition in TSST-1 induced TNFα secretion was 2.6 mM. The irrelevant peptide, T(144- 1δ3), was unable to inhibit TSST-1 induced TNFα secretion even at a concentration of 10 mM. EXAMPLE 8 MODIFICATION OF TSST-1

The peptide sequence corresponding to amino acid residues 47-60 of TSST-1 was identified as the superantigenic, MHC binding domain of TSST-1 in the Examples above. In order to narrow the peptide further to identify the effective epitope sequence, binding studies with mAbδ were performed on overlapping 10-mer peptides each containing additional amino acids within the 47-60 peptide. The studies showed that the sequence corresponding to δ1 -δ6 of TSST-1 , YYSPAF (amino acids δ-10 of SEQ ID NO:1), is the superantigenic peptide.

Utilizing standard site directed mutagenesis techniques (see for example, Current Protocols in Molecular Biology, Ausubel, et al., eds., 1989 Chapt. 8), single amino acid substitutions were made in tst, the gene encoding TSST-1 (Kreiswirth, B.N., et al., Mol. Gen. Genet., 208:84, 1987). Based on the results above, the gene was mutagenized in the region encoding amino acids δ1 -δ6. Once mutagenized, the altered genes were expressed in Staphylococcus aureus using standard electroporation and protein purification techniques. (Ausubel, et al., supra, Units 1 and 10).

When amino acid δδ was changed from alanine to threonine, the most significant effects were seen. Using the methods described in the Examples above, this mutant, designated TST (AδδT) (SEQ ID NO:4 with amino acid δδ substituted with threonine; was found to bind poorly to mAbδ, was not mitogenic and did not induce cytokine secretion from human PBMC. However, TST (AδδT) was active in being able to inhibit binding of native TSST-1 to human monocytes and in blocking TSST-1 induced mitogenesis and cytokine secretion. Therefore, residue δδ appears to be part of the precise site for TSST-1 binding to MHC class II molecules, which is required for TSST-1 mitogenic and superantigenic activities.

The present invention shows that the synthetic peptide T(47-60) was able to compete with ¹²⁵I-TSST-1 binding and that T(47-64) was able to compete with ¹²⁵I-SEA in binding to human monocytes in a dose dependent manner, suggesting that this region of the TSST-1 molecule is involved in binding to HLA-DR within the MHC class II molecules of human monocytes. T(47-60) by itself was unable to induce mitogenesis of human PBMC or to induce secretion of TNFα from co-cultures of human monocytes and T cells. The presence of a highly conserved sequence towards the carboxyl terminus of T(47-64), which is also found in SEΞA, SEE, and to a less extent in SEB, SEC1 , SEC3 and SED, also indicates that this unique conformational or primary sequence may be an important region for the binding of these related superantigens to MHC class II molecules of human monocytes, and thus may in part confer the superantig- enic activities of these staphylococcal exoproteins (FIGURE 8).

It is of considerable interest that the crystal structures of both TSST-1 and SEB demonstrate a striking similarity in their conformation even though their primary structure shares only limited amino acid sequence homology (G.S. Prasad, et al., Biochemistry, 32:13761-13766, 1993; S. Swaminathan, et al., Nature, 359:801-806, 1992). Based on the conformational data, it is remarkable that T(δ8-64) and its corresponding conserved region within SEB are similarly located within TSST-1 and SEB, respectively, each within loops with an open, extended conformation connecting the B strands 3 and 4 of the respective toxin molecule (G.S. Prasad, et al., supra; S. Swaminathan, et al, supra). These similarities in conformational structure between TSST-1 and SEB (and very likely between TSST-1 and SEA as well) provide additional insight that T(47-60) and its adjoining carboxyl region provide the necessary conformation for efficient binding of these staphylococcal toxins to MHC class II molecules of human monocytes.

Deposit of Materials

Cell Line ATCC Accession No. mAb1 ATCC HB 11473 mAb4 ATCC HB 11474 mAbδ ATCC HB 11475

This deposit has been made at the American Type Culture Collection, 1301 Parklawn Drive, Rockville, MD, USA (ATCC) under the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorgan¬ isms for the Purpose of Patent Procedure and the Regulations thereunder (Budapest Treaty). This assures maintenance of a viable culture for 30 years from the date of deposit. The organism will be made available by ATCC under the terms of the Budapest Treaty. Applicants assure permanent and unrestricted availability of the progeny of the culture to the public upon issuance of the pertinent US patent or upon laying open to the public of any US or foreign patent application, whichever comes first, and assure availability of the progeny to one determined by the US Commissioner of Patents and Trademarks to be entitled thereto according to 3δ USC §122 and the Com- missioner's rules pursuant thereto (including 37 CFR §1.14 with particular reference to 886 OG 638).

The assignee of the present application has agreed that if the culture deposit should die or be lost or destroyed when cultivated under suitable conditions, it will be promptly replaced on notification with a viable specimen of the same culture. Availability of the deposited strain is not to be construed as a license to practice the invention in contravention of the rights granted under the authority of any government in accordance with its patent laws.

The foregoing written specification identifies the particular peptides recognized by the antibodies produced by the above-noted cell lines. Consequently, the specification is considered to be sufficient to enable one skilled in the art to practice the invention without having to utilize the above-noted cell lines. The present invention is not to be limited in scope by the cell lines deposited since the deposited embodiment is intended as a single illustration of one aspect of the invention and any cell lines that are functionally equivalent are within the scope of this invention. The deposit of material does not constitute an admission that the written description herein contained is inadequate to enable the practice of any aspect of the invention, including the best mode thereof, nor is it to be construed as limiting the scope of the claims to the specific illustration that it represents. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and fall within the scope of the appended claims.

Although the invention has been described with reference to the presently preferred embodiment, it should be understood that various modifications can be made without departing from the spirit of the invention. Accordingly, the invention is limited only by the following claims.

SUMMARY OF SEQUENCES

SEQUENCE ID NO. 1 is the amino acid sequence FPSPYYSPAFTKGE which corresponds to amino acid residues 47-60 of TSST-1.

SEQUENCE ID NO. 2 is the amino acid sequence STNDNIKDLLDWYS which corresponds to amino acid residues 1 -14 of TSST-1.

SEQUENCE ID NO. 3 is the amino acid sequence FEYNTEKPPINIDEIKTIE which corresponds to amino acid residues 172-190 of TSST-1.

SEQUENCE ID NO. 4 is the amino acid sequence of TSST-1.

SEQUENCE ID NO. δ is the partial amino acid sequence of Staphylococcal enterotoxin SEB.

SEQUENCE ID NO. 6 is the partial amino acid sequence of Staphylococcal enterotoxin SEC1.

SEQUENCE ID NO. 7 is the partial amino acid sequence of Staphylococcal enterotoxin SEC3.

SEQUENCE ID NO. 8 is the partial amino acid sequence of Staphylococcal enterotoxin SED.

SEQUENCE ID NO. 9 is the partial amino acid sequence of Staphylococcal enterotoxin SEE.

SEQUENCE ID NO. 10 is the partial amino acid sequence of Staphylococcal enterotoxin SEA. SEQUENCE ID NO. 11 is the amino acid sequence of a portion of TSST-1 which shares homology with Staphylococcal enterotoxins (Figure 8).

SEQ ID NO: 11 is the amino acid sequence FPSPYYSPAFTKGEKVDL which corresponds to amino acid residues 47-64 of TSST-1.

SEQ ID NO: 12 is the amino acid sequence of SEQ ID NO:1 wherein alanine (A) is substituted with threonine (T).

SEQ ID NO: 13 is the amino acid sequence YRSSDKTCCY, which corresponds to amino acid residues 144-1δ3 of TSST-1.

SEQUENCE LISTING

(1) GENERAL INFORMATION:

(i) APPLICANT: Chow MD, Anthony W.

Ku Ph.D. , Winnie W.S.

(ii) TITLE OF INVENTION: IMMUNOTHERAPEUTIC PEPTIDES

(iii) NUMBER OF SEQUENCES: 13

(iv) CORRESPONDENCE ADDRESS:

(A) ADDRESSEE: Spensley Horn Jubas & Lubitz

(B) STREET: 1880 Century Park East, Suie 500

(C) CITY: Los Angeles

(D) STATE: California

(E) COUNTRY: USA

(F) ZIP: 90067

(v) COMPUTER READABLE FORM:

(A) MEDIUM TYPE: Floppy disk

(B) COMPUTER: IBM PC compatible

(C) OPERATING SYSTEM: PC-DOS/MS-DOS

(D) SOFTWARE: Patentin Release #1.0, Version #1.25

(vi) CURRENT APPLICATION DATA:

(A) APPLICATION NUMBER: PCT

(B) FILING DATE: 03-MAY-1994

(C) CLASSIFICATION:

(viii) ATTORNEY/AGENT INFORMATION:

(A) NAME: Wetherell, Jr. Ph.D., John R.

(B) REGISTRATION NUMBER: 31,678

(C) REFERENCE/DOCKET NUMBER: FD3537 PCT

(ix) TELECOMMUNICATION INFORMATION:

(A) TELEPHONE: (619) 455-5100

(B) TELEFAX: (619) 455-5110

(2) INFORMATION FOR SEQ ID NO:l:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 14 amino acids

(B) TYPE: amino acid (C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..14

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:l:

Phe Pro Ser Pro Tyr Tyr Ser Pro Ala Phe Thr Lys Gly Glu 1 5 10

(2) INFORMATION FOR SEQ ID NO:2:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 14 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..14

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:

Ser Thr Asn Asp Asn lie Lys Asp Leu Leu Asp Trp Tyr Ser

1 5 10

(2) INFORMATION FOR SEQ ID NO:3:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 19 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY:^"linear (ii) MOLECULE TYPE: peptide

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..19

(xi) SEQUENCE DESCRIPTION : SEQ ID NO : 3 :

Phe Glu Tyr Asn Thr Glu Lys Pro Pro lie Asn lie Asp Glu lie Lys 1 5 10 15

Thr He Glu

(2) INFORMATION FOR SEQ ID N0:4:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 194 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(vii) IMMEDIATE SOURCE: (B) CLONE: TSST-1

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..194

(xi) SEQUENCE DESCRIPTION : SEQ ID NO : 4 :

Ser Thr Asn Asp Asn He Lys Asp Leu Leu Asp Trp Tyr Ser Ser Gly 1 5 10 15

Ser Asp Thr Phe Thr Asn Ser Glu Val Leu Asp Asn Ser Leu Gly Ser 20 25 30

Met Arg He Lys Asn Thr Asp Gly Ser He Ser Leu He He Phe Pro

35 40 45 Ser Pro Tyr Tyr Ser Pro Ala Phe Thr Lys Gly Glu Lys Val Asp Leu 50 55 60

Asn Thr Lys Arg Thr Lys Lys Ser Asn His Thr Ser Glu Gly Thr Tyr 65 70 75 80

He His Phe Gin He Ser Gly Val Thr Asn Thr Glu Lys Leu Pro Thr 85 90 95

Pro He Glu Leu Pro Leu Lys Val Lys Val His Gly Lys Asp Ser Pro 100 105 110

Leu Lys Tyr Trp Pro Lys Phe Asp Lys Lys Gin Leu Ala He Ser Thr 115 120 125

Leu Asp Phe Glu He Arg His Gin Leu Thr Gin He His Gly Leu Tyr 130 135 140

Arg Ser Ser Asp Lys Thr Gly Gly Tyr Trp Lys He Thr Met Asn Asp 145 150 155 160

Gly Ser Thr Tyr Gin Ser Asp Leu Ser Lys Lys Phe Glu Tyr Asn Thr 165 170 175

Glu Lys Pro Pro He Asn He Asp Glu He Lys Thr He Glu Ala Glu 180 185 190

He Asn

(2) INFORMATION FOR SEQ ID NO:5:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 7 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(vii) IMMEDIATE SOURCE: (B) CLONE: SEB ( ix) FEATURE :

(A) NAME/KEY: Peptide

(B) LOCATION: 1..7

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:

Lys Asp Lys Tyr Val Asp Val 1 5

(2) INFORMATION FOR SEQ ID NO:6:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 7 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(vii) IMMEDIATE SOURCE: (B) CLONE: SEC1

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..7

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:

Lys Asp Glu Val Val Asp Val 1 5

(2) INFORMATION FOR SEQ ID NO:7:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 7 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide (vii) IMMEDIATE SOURCE: (B) CLONE: SEC3

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..7

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:

Lys Asp Glu Val Val Asp Val 1 5

(2) INFORMATION FOR SEQ ID NO:8:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 7 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(vii) IMMEDIATE SOURCE: (B) CLONE: SED

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..7

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:

Phe Lys Ser Lys Asn Val Asp 1 5

(2) INFORMATION FOR SEQ ID NO:9:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 7 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY:^"linear (ii) MOLECULE TYPE: peptide

(vii) IMMEDIATE SOURCE: (B) CLONE: SEE

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..7

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:

Lys Gly Lys Lys Val Asp Leu 1 5

(2) INFORMATION FOR SEQ ID NO:10:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 7 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(vii) IMMEDIATE SOURCE: (B) CLONE: SEA

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..7

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:

Lys Gly Lys Lys Val Asp Leu 1 5 (2) INFORMATION FOR SEQ ID NO:11:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 18 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(vii) IMMEDIATE SOURCE: (B) CLONE: TSST-1

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..18

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:

Phe Pro Ser Arg Tyr Tyr Ser Pro Ala Phe Thr Lys Gly Glu Lys Val 1 5 10 15

Asp Leu

(2) INFORMATION FOR SEQ ID NO:12:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 14 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..14 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:

Phe Pro Ser Pro Tyr Tyr Ser Pro Thr Phe Thr Lys Gly Glu 1 5 10

(2) INFORMATION FOR SEQ ID NO:13:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 10 amino acids

(B) TYPE: amino acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(ix) FEATURE:

(A) NAME/KEY: Peptide

(B) LOCATION: 1..10

(xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:

Tyr Arg Ser Ser Asp Lys Thr Cys Cys Tyr 1 5 10

Claims

1. An isolated synthetic peptide, comprising SEQ ID NO:1.

2. An isolated synthetic peptide comprising SEQ ID NO:2.

3. An isolated synthetic peptide comprising SEQ ID NO:3.

4. The peptide of claim 1 , wherein the peptide binds to a peripheral blood mononuclear cell (PBMC) receptor.

5. The peptide of claim 4, wherein the PBMC is a monocyte.

6. The peptide of claim 1 , wherein the peptide stimulates the secretion of a cytokine.

7. The peptide of claim 6, wherein the cytokine is selected from the group consisting of TNFalpha, interleukin 1 and interleukin 6.

8. The peptide as in any of claims 1 , 2 or 3, wherein the peptide is a hematopoietic cell mitogen.

9. The peptide of claim 8, wherein the hematopoietic cell is a T-cell.

10. An isolated synthetic peptide variant of TSST-1 , wherein at least one amino acid in positions 51 through 56 from the amino terminus of wild- type TSST-1 toxin as in SEQ ID NO:4 is replaced by a non-wild-type amino acid.

11. The peptide of claim 10, wherein amino acid 55 from the amino terminus of wild-type TSST-1 as in SEQ ID NO:4 is replaced by a non-wild-type amino acid.

12. The peptide of claim 11 , wherein the non-wild-type amino acid is an amino acid having a polar side chain.

13. The peptide of claim 12, wherein the non-wild-type is threonine.

14. The peptide of claim 12, wherein the non-wild-type is glutamine.

15. The peptide of claim 12, wherein the non-wild-type is asparagine.

16. An isolated synthetic peptide consisting of the amino acid sequence:

^YYSPAFX_g wherein X, or X., are independently 0 to 10 amino acids in length.

17. The peptide of claim 16, wherein X→ or X_g are independently 0 to 4 amino acids in length.

18. An antibody which binds to the amino acid sequence of SEQ ID NO:1.

19. The antibody of claim 18, wherein the antibody is polyclonal.

20. The antibody of claim 18, wherein the antibody is monoclonal.

21. The antibody of claim 20 which has the specificity of the monoclonal antibody produced by cell line ATCC HB 11475.

22. The antibody of claim 21 which is produced by ATCC HB 11475.

23. An antibody which binds to the amino acid sequence of SEQ ID NO:2.

24. The antibody of claim 23, wherein the antibody is polyclonal.

25. The antibody of claim 23, wherein the antibody is monoclonal.

26. The antibody of claim 25 which has the specificity of the monoclonal antibody produced by cell line ATCC HB 11473.

27. The antibody of claim 26 which is produced by ATCC HB 11473.

28. An antibody which binds to the amino acid sequence of SEQ ID NO:3.

29. The antibody of claim 28 which is polyclonal.

30. The antibody of claim 28 which is monoclonal.

31. The antibody of claim 30 which has the specificity of an antibody produced by cell line ATCC HB 11474.

32. The antibody of claim 31 which is produced by ATCC HB 11474.

33. A method of treating a subject having or at risk of having an immuno¬ pathological disorder associated with a polypeptide comprising a peptide selected from the group of polypeptides consisting of SEQ ID NO:1 , SEQ ID NO:2, and SEQ ID NO:3, comprising administering to the subject an immunotherapeutically effective amount of a therapeutic agent which ameliorates the disorder.

34. The method of claim 33, wherein the therapeutic agent is an antibody which binds to a synthetic peptide selected from the group of peptides consisting of SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3.

35. The method of claim 34, wherein the antibody has the binding specificity of an antibody produced by a cell line selected from the group consisting of ATCC HB 11473, ATCC HB 11474, and ATCC HB 11475.

36. The method of claim 33, wherein the therapeutic agent is a synthetic peptide comprising a peptide having an amino acid sequence selected from the group consisting of SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3 and conservative variations thereof.

37. The method of claim 33, wherein the immunopathological disorder is superantigen-associated.

38. The method of claim 37, wherein the superantigen is selected from the group consisting of toxic shock syndrome toxin-1, a Staphylococcus enterotoxin and a Streptococcus pyrogenic exotoxin.

39. The method of claim 38, wherein the Staphylococcus enterotoxin is selected from the group consisting of SEA, SEB, SEC1 , SEC3, SED and SEE.

40. The method of claim 33, wherein the immunopathological disorder is selected from the group consisting of toxic shock syndrome, rheumatoid arthritis, systemic lupus erythematosus, sepsis syndrome and acquired immune deficiency syndrome.

41. The method of claim 33, wherein the subject is a human.

42. The method of claim 33, wherein the thereapeutic agent is an anti- idiotype antibody.

43. The method of claim 42, wherein the anti-idiotype antibody binds to a paratope of an antibody which binds to an amino acid sequence selected from the group consisting of SEQ ID NO:1 , SEQ ID NO:2 and SEQ ID NO:3.

44. An isolated polynucleotide sequence which encodes the polypeptide of claim 10.

45. An isolated polynucleotide sequence which encodes the peptide of SEQ ID NO:1.

46. An isolated polynucleotide sequence which encodes the peptide of SEQ ID NO:2.

47. An isolated polynucleotide sequence which encodes the peptide of SEQ ID NO:3.

48. A kit useful for the detection of a target molecule indicative of an immunopathological disease associated with a polypeptide comprising a peptide selected from the group consisting of SEQ ID NO:1 , SEQ ID NO:2 and SEQ ID NO:3, the kit comprising a carrier means being compartmentalized to receive in close confinement therein one or more containers comprising a container containing a probe specifically reactive with the peptide.

49. The kit of claim 48, wherein the probe is an antibody.

50. The kit of claim 49, wherein the antibody is detectably labelled.

51. A method of treating a subject having or at risk of having an immuno¬ pathological disorder associated with a polypeptide comprising a peptide selected from the group of polypeptides consisting of SEQ ID NO.1, SEQ ID NO:2, and SEQ ID NO:3; which method comprises administering to the subject an immunotherapeutically effective amount of a TSST-1 variant which ameliorates the disorder.

52. The method of claim 1, wherein the TSST-1 variant has at least one amino acid in positions 51 through 56 from the amino terminus of wild- type TSST-1 toxin as in SEQ ID NO:4 replaced by a non-wild-type amino acid.

53. A method of diagnosing an immunopathological disorder associated with TSST-1 comprising: a. isolating a sample from a subject suspected of having the disorder; b. contacting the sample with an antibody that binds to TSST-1 ; and c. detecting the binding of the antibody to TSST-1.

54. The method of claim 53, wherein the sample is blood.

55. The method of claim 53, wherein the antibody has the binding specificity of an antibody selected from the group consisting of ATCC HB 11473, ATCC HB 11474, and ATCC HB 11475. -ea¬

se. A pharmaceutical composition comprising at least one dose of an immunogenically effective amount of a peptide selected from the group consisting of a polypeptide comprising YYSPAF, SEQ ID NO:1, SEQ ID NO:2, or SEQ ID NO:3, in a pharmacological carrier.

57. A pharmaceutical composition comprising at least one dose of an immunogenically effective amount of a monoclonal antibody selected from the group consisting of ATCC HB 11473, ATCC HB 11474, and ATCC HB 11475, in a pharmacological carrier.

58. The pharmaceutical composition of claim 67, wherein the monoclonal antibody is human.

59. A pharmaceutical composition comprising at least one dose of the peptide of claim 16.

60. A synthetic adjuvant comprising a synthetic peptide selected from the group of peptides consisting of SEQ ID NO:1 , SEQ ID NO:2, and SEQ ID NO:3 conjugated to a second peptide or polypeptide.

61. A method for inducing an immune response to a peptide or polypeptide of interest which comprises administering to a subject a synthetic adjuvant comprising a synthetic peptide selected from the groups of peptides consisting of SEQ ID NO:1 , SEQ ID NO:2, and SEQ ID NO:3 conjugated to the peptide or polypeptide of interest.