Toxic shock syndrome toxin-1 (TSST-1) is a 22 kilodalton S. aureus exotoxin implicated in the pathogenesis of TSS. TSST-1 activates monocytes to release interleukin 1 and tumor necrosis factor and causes the proliferation of peripheral blood mononuclear cells. We have preliminary data which indicates that TSST-1 binds to Class II major histocompatibility complex (MHC) molecules expressed on B cells and monocytes. We propose to analyze the nature of this interaction. (1) We will ascertain the identity of the TSST-1 binding heterodimer with HLA-DR, HLADP or HLADQ by comparing peptide maps, two dimensional gel electrophoresis patterns and N terminal amino acid (a.a.) sequences. Cells from MHC Class II deficient patients will be used to ascertain that no other cell surface molecules bind TSST-1. We will examine TSST-1 binding to MHC Class II molecules expressed by L cell transfectants and to MHC Class II molecules incorporated into liposomes to ascertain that no other molecules contribute to the binding of TSST-1 to MHC Class II molecules. 2) The determinants on MHC Class II molecules involved in TSST-1 binding will be studied by examining the contribution of sugar residues and of isolated MHC Class II alpha and beta chains to TSST-1 binding, by performing mAb inhibition studies, and by examining TSST-1 binding to L cell transfectants which express isotype mismatched alpha and beta chains or chains with single a.a. substitutions. 3) The TSST-1 site involved in binding to MHC Class II molecules will be investigated by examining the activity of truncated TSST-1 peptides and of TSST-1 mutants generated by oligonucleotide site directed mutagenesis. 4) A mouse model of TSST-1 MHC Class II interaction will be developed because of the availability of better reagents in the murine system and for future in vivo studies. The role of IA vs. IE molecules will be assessed using deletion mutants and the determinants on these molecules involved in TSST-1 binding will be mapped using L cells transfected with exon shuffled alpha and beta chains and chains with point mutations and in phase insertions. The proposed studies define a new function for MHC Class II molecules as receptors for bacterial toxins and will enhance our understanding of diseases caused by TSST-1 and by related bacterial toxins. The potential of TSST-1 antagonists to disrupt the quaternary complex of MHC Class II molecule - peptide antigen - T cell receptor - CD4 has important implications for therapeutic intervention in diseases associated with chronic T cell activation e.g. autoimmune, graft versus host and allergic diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI027411-03
Application #
3141600
Study Section
Experimental Immunology Study Section (EI)
Project Start
1990-06-01
Project End
1993-05-31
Budget Start
1992-06-01
Budget End
1993-05-31
Support Year
3
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Children's Hospital Boston
Department
Type
DUNS #
076593722
City
Boston
State
MA
Country
United States
Zip Code
02115
Ramesh, N; Horner, A; Ahern, D et al. (1995) Bacterial superantigens induce the proliferation of resting gamma/delta receptor bearing T cells. Immunol Invest 24:713-24
Trede, N S; Tsytsykova, A V; Chatila, T et al. (1995) Transcriptional activation of the human TNF-alpha promoter by superantigen in human monocytic cells: role of NF-kappa B. J Immunol 155:902-8
Wang, A V; Scholl, P R; Geha, R S (1994) Physical and functional association of the high affinity immunoglobulin G receptor (Fc gamma RI) with the kinases Hck and Lyn. J Exp Med 180:1165-70
Morio, T; Geha, R S; Chatila, T A (1994) Engagement of MHC class II molecules by staphylococcal superantigens activates src-type protein tyrosine kinases. Eur J Immunol 24:651-8
Hoeger, P H; Tepper, M A; Faith, A et al. (1994) Immunosuppressant deoxyspergualin inhibits antigen processing in monocytes. J Immunol 153:3908-16
Ramesh, N; Parronchi, P; Ahern, D et al. (1994) A toxic shock syndrome toxin-1 peptide that shows homology to amino acids 180-193 of mycobacterial heat shock protein 65 is presented as conventional antigen. Immunol Invest 23:381-91
Fuleihan, R; Trede, N; Chatila, T et al. (1994) Superantigens activate HIV-1 gene expression in monocytic cells. Clin Immunol Immunopathol 72:357-61
Scholl, P R; Geha, R S (1993) Physical association between the high-affinity IgG receptor (Fc gamma RI) and the gamma subunit of the high-affinity IgE receptor (Fc epsilon RI gamma). Proc Natl Acad Sci U S A 90:8847-50
Scholl, P R; Ahern, D; Geha, R S (1992) Protein tyrosine phosphorylation induced via the IgG receptors Fc gamma Ri and Fc gamma RII in the human monocytic cell line THP-1. J Immunol 149:1751-7
Ramesh, N; Spertini, F; Scholl, P et al. (1992) A toxic shock syndrome toxin-1 peptide that shows homology to mycobacterial heat shock protein 18 is presented as conventional antigen to T cells by multiple HLA-DR alleles. J Immunol 148:1025-30

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