title: Activation of human T cells by toxic shock syndrome toxin-1: the toxin-binding structures expressed on human lymphoid cells acting as accessory cells are HLA class II molecules.
abstract: Toxic shock syndrome toxin-1 (TSST-1)-binding assay using 125I-labeled TSST-1 showed the presence of specific TSST-1 binding in a B cell fraction of human peripheral blood mononuclear cells and L cells transfected with DR2 genes or DR4 genes but not in a T cell fraction and control L cells. Fixation with paraformaldehyde, an inhibitor of antigen processing, did not remove TSST-1-binding activity of the transfectants. Binding of 125I-labeled TSST-1 to the transfectants was reduced by an anti-DR monoclonal antibody. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of a single band with TSST-1-binding activity and the same migration pattern as DR heterodimers. TSST-1-induced T cell responses, proliferation and interleukin 2 (IL2) production were observed in the presence of the transfectants but not in the presence of control L cells, while concanavalin A-induced IL2 production was observed in the presence of either the transfectants or control L cells. Presence of an anti-DR monoclonal antibody inhibited the TSST-1-induced responses. Paraformaldehyde-fixed Daudi cells were effective in supporting TSST-1-induced IL2 production by T cells. These results indicate that HLA class II molecules directly bind intact TSST-1 and perform an essential role as the TSST-1-binding structures on accessory cells in T cell activation by the toxin.
authors.affiliation: Department of Microbiology, Tokyo Women's Medical College, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uchiyama
authors.forename: K
authors.initials: K
authors.lastname: Imanishi
authors.forename: S
authors.initials: S
authors.lastname: Saito
authors.forename: M
authors.initials: M
authors.lastname: Araake
authors.forename: X J
authors.initials: XJ
authors.lastname: Yan
authors.forename: H
authors.initials: H
authors.lastname: Fujikawa
authors.forename: H
authors.initials: H
authors.lastname: Igarashi
authors.forename: H
authors.initials: H
authors.lastname: Kato
authors.forename: F
authors.initials: F
authors.lastname: Obata
authors.forename: N
authors.initials: N
authors.lastname: Kashiwagi
mesh_terms: D000938:Antigen-Presenting Cells / Q000502:physiology*; D001427:Bacterial Toxins; D004591:Electrophoresis, Polyacrylamide Gel; D004768:Enterotoxins / Q000378:metabolism* / Q000494:pharmacology; D006684:HLA-DR Antigens / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000187:drug effects*; D013211:Staphylococcus aureus / Q000472:pathogenicity*; D018089:Superantigens; D013601:T-Lymphocytes / Q000378:metabolism*; D014162:Transfection
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D006684:HLA-DR Antigens; D007376:Interleukin-2; D018089:Superantigens; C049463:enterotoxin E, Staphylococcal; C030107:enterotoxin F, Staphylococcal