THE V-BETA COMPLEMENTARITY-DETERMINING REGION-1 OF A MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) CLASS-I-RESTRICTED T-CELL RECEPTOR IS INVOLVED IN THE RECOGNITION OF PEPTIDE MHC-I AND SUPERANTIGEN/MHC-II COMPLEX/

We investigated the role of the complementarity determining region 1 ( CDR1) of T cell receptor (TCR) beta chain both in antigen/major histoc ompatibility complex I (MHC I) and in superantigen (SAg)/MHC II comple x recognition. Residues 26 to 31 of the Vbeta10 domain of a TCR derive d from an H-2K(d)-restricted cytotoxic clone were individually changed to alanine, using site-directed mutagenesis, and the mutated TCR beta chains were transfected along with the wild-type TCR alpha chain into a TCRalpha-beta- T hybridoma. These mutations affected antigen/H-2K(d ) complex recognition, although to a different extent, as estimated by interleukin 2 production. Certain mutations also affected differently the recognition of two Staphylococcal toxins, exfoliative toxin and S taphylococcal enterotoxin C2, presented by HLA-DR1. Whereas mutation o f residues D30 or T31 affect the recognition of both toxins, residues T26, L27, and H29 are critical for the recognition of only one of the SAgs. These observations demonstrate the participation of the CDR1 reg ion in the recognition of peptide/MHC class I as well as SAg/MHC II co mplexes.