title: Mitogenic toxins as MHC class II-dependent probes for T cell antigen receptors.
abstract: The enterotoxins produced by Staphylococcus aureus (SE) are prototypes of a group of microbial exoproteins that share a potent mitogenic activity for T lymphocytes of several species. These exoproteins use a very effective novel mechanism of T lymphocyte stimulation. For stimulation of all types of T cells (CD4+, CD8+ as well as gamma delta TCR+) the presence of allogeneic or xenogeneic MHC class II molecules on accessory or target cells is required. This requirement is reflected by a selective binding of the toxins to MHC class II molecules. The toxins stimulate preferentially but not exclusively alpha beta TCR+ T cells carrying certain TCR V beta s. A current model suggests that the toxins are functionally bivalent molecules, crosslinking variable parts of the TCR with MHC class II molecules on the accessory or target cells. Of all T cell mitogens the toxins thus most closely simulate T cell recognition of specific antigen. The differential pattern of reactivity of human and murine T cells with various toxins suggests that the toxins have been adapted to the host's immune system in evolution.
authors.affiliation: I. Department of Medicine, University of Mainz, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Fleischer
authors.forename: H W
authors.initials: HW
authors.lastname: Mittrücker
authors.forename: B
authors.initials: B
authors.lastname: Metzroth
authors.forename: M
authors.initials: M
authors.lastname: Braun
authors.forename: U
authors.initials: U
authors.lastname: Hartwig
mesh_terms: D004768:Enterotoxins / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D008934:Mitogens; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D004768:Enterotoxins; D000949:Histocompatibility Antigens Class II; D008934:Mitogens; D011948:Receptors, Antigen, T-Cell