Molecular characterization and role in T cell activation of staphylococcal enterotoxin A binding to the HLA-DR alpha-chain.

摘要: Superantigens bind to MHC class II-positive cells and stimulate T lymphocytes expressing specific V beta regions of the TCR. Two distinct staphylococcal enterotoxin A superantigen (SEA) have been shown affect binding II molecules. Results presented here demonstrate for first time that SEA-DR interaction can be affected by mutations on alpha-chain. Furthermore, we precisely mapped SEA N-terminal domain with alpha1 HLA-DR. Scatchard analysis using DAP transfected mutant molecules showed a role residue DR alpha K39 in SEA. Also, complementation experiments revealed an between F47 position alphaQ18 outer loop These interactions SEAF47 alpha-chain are critical, as they allow recognition otherwise nonreactive beta1+ cell hybridoma induction tyrosine phosphorylation through