Selective stimulation of human T cells with streptococcal erythrogenic toxins A and B
Abe, J.; Forrester, J.; Nakahara, T.; Lafferty, J.A.; Kotzin, B.L.; Leung, D.Y.
Journal of Immunology 146(11): 3747-3750
1991
ISSN/ISBN: 0022-1767 PMID: 1903412 Document Number: 386908
Streptococcal exotoxins have been implicated in the pathogenesis of a toxic shock-like syndrome and scarlet fever. Previous studies have demonstrated that these toxins are potent stimulators of human T cells and have structural homology to staphylococcal enterotoxins. In the current study, we investigated the mechanism by which streptococcal erythrogenic toxins type A (SPEA) and B (SPEB) activate T cells and compared it with anti-CD3 and the known "superantigen" staphylococcal enterotoxin B. SPEA was found to selectively activate T cells bearing V.beta.8, V.beta.12, and V.beta.14, whereas SPEB selectively activated T cells bearing V.beta.2 and V.beta.8. Furthermore, fibroblasts transfected with MHC class II molecules were capable of presenting SPEA and SPEB to purified T cells. The T cell response to these toxins, however, was not MHC-restricted. Although the streptococcal exotoxins stimulated both CD4+ and CD8+ T cells, SPEA but not SPEB stimulated the CD4+ T cell subset proportionately more than the CD8+ T cell subset. Our results indicate that SPEA and SPEB, like the staphylococcal enterotoxins, are superantigens and suggest a mechanism by which they may mediate particular systemic syndromes associated with streptococcal infections.