Peptide Recognition by Two HLA-A2/Tax11–19-Specific T Cell Clones in Relationship to Their MHC/Peptide/TCR Crystal Structures

摘要: The crystal structures of two human TCRs specific for a HTLV-I Tax peptide bound to HLA-A2 were recently determined, the first time allowing functional comparison which MHC/peptide/TCR are known. Extensive amino acid substitutions show that native residues optimal at each position. A prominent feature TCR contact surface is deep pocket accommodates tyrosine position 5 peptide. For one these TCRs, this highly aromatic residues. In other structure, larger, many different be accommodated. CTL clones also major differences in specificity several residues, including side chains not directly contacted by TCR. Despite clones, peptides distinct five or six positions from Tax11-19 induce activity, indicating substantial changes tolerated. Human with limited sequence homology represent partial agonists clones. properties highlight structural features determine and cross-reactivity MHC-bound peptides.