title: Role of human major histocompatibility complex DQ molecules in superantigenicity of streptococcus-derived protein.
abstract: Antigenicity of peptic extract from type 12 group A streptococci (PEAST12) for T cells was examined in major histocompatibility complex (MHC) class II transgenic mice. PEAST12 was mitogenic for murine T cells when antigen-presenting cells were obtained from human MHC (HLA)-DQ4 alpha beta transgenic mice or from DQ6 alpha beta transgenic mice but was not mitogenic in DR alpha transgenic, DR51 alpha beta transgenic, E alpha transgenic, or nontransgenic mice. In addition, PEAST12 showed mitogenicity for murine T cells in DQ4 alpha singly transgenic mice but not in DQ4 beta singly transgenic mice. T-cell stimulation by PEAST12 was unrestricted by but dependent on the expression of HLA-DQ molecules on antigen-presenting cells, and PEAST12 selectively activated T-cell receptor V beta 11-, V beta 15-, and V beta 18-positive T cells in mice. We propose that PEAST12 contains a superantigen which binds preferentially to the alpha-chain of HLA-DQ molecules. The well-known phenomenon that peptic extracts from group A streptococci are mitogenic in humans but not in mice is likely due to structural differences in MHC class II molecules between these two species of mammals.
authors.affiliation: Department of Genetics, Kyushu University, Fukuoka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Esaki
authors.forename: Y
authors.initials: Y
authors.lastname: Fukui
authors.forename: T
authors.initials: T
authors.lastname: Sudo
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Inamitsu
authors.forename: Y
authors.initials: Y
authors.lastname: Nishimura
authors.forename: K
authors.initials: K
authors.lastname: Hirokawa
authors.forename: A
authors.initials: A
authors.lastname: Kimura
authors.forename: T
authors.initials: T
authors.lastname: Sasazuki
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000276:immunology*; D001483:Base Sequence; D006683:HLA-DQ Antigens / Q000502:physiology*; D006684:HLA-DR Antigens / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis; D013297:Streptococcus pyogenes / Q000276:immunology*; D018089:Superantigens / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D001426:Bacterial Proteins; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens