Staphylococcal enterotoxins (SE) are superantigens that bind to MHC class II molecules and activate T lymphocytes via the T cell receptor (TCR) Vβ domain. By analogy with T cell responses to conventional peptide antigens, it might be predicted that CD4 (MHC class II restricted) cells would respond better to SE than CD8 (MHC class I restricted) cells. Here we summarize evidence that in fact CD8 cells respond as well as CD4 cells to SE both in vitro and in vivo. These findings emphasize the unique character of TCR-superantigen interactions.
