title: Isolation of a new superantigen with potent mitogenic activity to murine T cells from Streptococcus pyogenes.
abstract: A mitogenic substance on murine lymphocytes was detected in the culture supernate of Streptococcus pyogenes type 12 strain. This substance had a molecular weight of 28,000 and pI 9.2, and was designated as S. pyogenes mitogen (SPM). The proliferative response of C3H/HeN spleen cells began at 1 ng ml-1 and reached a maximal response at 100 ng ml-1 of SPM for 4 days culture. Anti-Thy 1.2 mAb and complement-treated spleen cells abrogated the proliferative response to any dose of SPM. Although the anti-major histocompatibility complex class 1 mAbs had no blocking effect on proliferation by SPM, this proliferation was substantially inhibited by the addition of either anti-I-A or anti-I-E mAb, and complete inhibition was produced by the addition of both mAbs. Fixed antigen-presenting cells still induced T cell proliferation by SPM. A significant expansion of T cells bearing V beta 13 T-cell receptor was observed up to 73% among the Thy 1.2+ cells in cultures stimulated with SPM, indicating expansion in a V beta-specific manner. Immunoblotting of IEF-separated proteins showed that anti-streptococcal pyrogenic exotoxin (SPE) C reacted with a protein of pI 6.9 and anti-SPEB did not show any reactivity. SPEA was reported to expand V beta 8.1 and 8.2 bearing murine T cells, and SPM did not. SPM also exhibited potent mitogenic activity on human T cells and V beta 21+ T cells were selectively expanded. These results lead to the conclusion that SPM was neither SPEA, B nor C, but a new protein belonging to a group of streptococcal superantigens with activity on not only human but also murine lymphocytes.
authors.affiliation: Department of Microbiology, Tohoku University School of Dentistry, Sendai Japan.
authors.forename: E
authors.initials: E
authors.lastname: Nemoto
authors.forename: H
authors.initials: H
authors.lastname: Rikiishi
authors.forename: S
authors.initials: S
authors.lastname: Sugawara
authors.forename: S
authors.initials: S
authors.lastname: Okamoto
authors.forename: K
authors.initials: K
authors.lastname: Tamura
authors.forename: Y
authors.initials: Y
authors.lastname: Maruyama
authors.forename: K
authors.initials: K
authors.lastname: Kumagai
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000276:immunology; D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D001426:Bacterial Proteins; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D005098:Exotoxins / Q000737:chemistry; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D007526:Isoelectric Point; D008213:Lymphocyte Activation; D008565:Membrane Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008934:Mitogens / Q000737:chemistry; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D013297:Streptococcus pyogenes / Q000276:immunology*; D018089:Superantigens / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D005098:Exotoxins; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D008565:Membrane Proteins; D008934:Mitogens; D016693:Receptors, Antigen, T-Cell, alpha-beta; C117980:SpeA protein, Streptococcus pyogenes; D018089:Superantigens; C027951:erythrogenic toxin