Contribution of the TCR alpha-chain to the differential recognition of bacterial and retroviral superantigens.

The TCR alpha-chain has been implicated in superantigen recognition by some T cells. In this study, recognition of a retroviral (minor lymphocyte stimulating Ag-1, Mls-1) and a bacterial (staphylococcal enterotoxin B, SEB) superantigen by T cells expressing an identical (transgenic) V beta 8.1 beta-chain and either a V alpha 2+ or V alpha 11+ alpha-chain have been compared. Individual hybridomas were found to vary in their recognition of the two superantigens. Whereas some T cell hybridomas recognized both superantigens comparably, other hybridomas preferentially recognized either Mls-1 or SEB, indicating that the contribution of the TCR alpha-chain to recognition of these superantigens is not equivalent. The degree of heterogeneity in recognition varied between the V alpha 2+ and V alpha 11+ hybridomas, although there were individual hybridomas within each group with distinct patterns of reactivity that varied only in CDR3 alpha. These data are consistent with recent evidence that recognition of Mls-1 and SEB involves distinct TCR/MHC interactions.