Cross-linking of MHC class II molecules by staphylococcal enterotoxin A is essential for antigen-presenting cell and T cell activation.

摘要: Two binding sites for MHC class II have previously been identified on opposite sides of the superantigen, staphylococcal enterotoxin A (SEA). The mediate separate reactions with nonoverlapping regions II, and in solution cause SEA to complex purified HLA-DR1 form DR1.SEA2 trimers. Here, a set complementary II-binding mutants was used study interaction cell surface II. results indicate that both are required same toxin molecule maximal activity, demonstrating simultaneous ligation two molecules APCs by single is essential effective superantigen function. Coalescence protein tyrosine kinase activation contributes induction cell:cell adhesion, pro-inflammatory cytokine gene transcription, T proliferation.