T-Cell Cytotoxicity Assays for Studying the Functional Interaction Between the Superantigen Staphylococcal Enterotoxin A and T-Cell Receptors

The superantigens (SAgs) staphylococcal enterotoxins (SEs) are produced by certain strains of Staphylococcus aureus and comprise structurally related bacterial proteins, which are among the most potent mitogens known for murine and human T lymphocytes (1 ,2 ). T-cell activation induced by SEs involves binding to constant parts of major histocompatibility complex (MHC) class II molecules and subsequent interaction with T cells expressing certain T-cell receptor (TCR) Vβ chains (3 ,4 ). The binding of SAgs to MHC class II molecules does not require processing and structural mutations, and biochemical experiments have demonstrated that the amino acids involved are distant from the antigen binding groove.