title: [Stimulation of the immune system by microbial "superantigens"].
abstract: The enterotoxins and the toxic-shock-syndrome toxin-1 of Staphylococcus aureus, the erythrogenic toxins of Streptococcus pyogenes as well as a still uncharacterized exoprotein of Mycoplasma arthritidis belong to a family of exotoxins, that have in common a potent mitogenic activity for T lymphocytes of several species. These proteins stimulate CD4(+)- and CD8+ T-lymphocytes by cross-linking the T-cell-antigen receptor with MHC-class-II molecules on accessory or target cells. They are functionally bivalent molecules having distinct interaction sites for variable parts of the T-cell receptor and for nonpolymorphic parts of MHC-class-II molecules. Due to their preferential action on T cells expressing certain V beta-parts of the T-cell receptor the designation "superantigens" has been proposed. The mechanism of T-cell stimulation has apparently been conserved in evolution and has been adapted to the host's T-cell-receptor repertoire. The T cells stimulating activity apparently contributes to the pathogenesis of certain infectious diseases. Noteworthy, mice express endogenous "superantigens" that have similar properties.
authors.affiliation: I. Medizinische Klinik und Poliklinik, Universität Mainz.
authors.forename: B
authors.initials: B
authors.lastname: Fleischer
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000276:immunology*; D004768:Enterotoxins / Q000276:immunology; D005098:Exotoxins / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D008565:Membrane Proteins; D013211:Staphylococcus aureus; D013297:Streptococcus pyogenes; D018089:Superantigens; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; D005098:Exotoxins; D008565:Membrane Proteins; C117980:SpeA protein, Streptococcus pyogenes; D018089:Superantigens; C030107:enterotoxin F, Staphylococcal; C027951:erythrogenic toxin
vernacular_title: Stimulation des Immunsystems durch mikrobielle "Superantigene".