FIG. 2.

Requirement of conserved amino acid positions for recognition of the Tax11-19 peptide. (Top) Crystal structure representation of interactions between TCR-B7 CDR3 regions and HLA-A*0201 complexed with Tax11-19 peptide. Only amino acids 4 to 8 of the Tax11-19 peptide are presented. Amino acids that are conserved in the CDR3 beta chain among T-cell clones are indicated by arrows. Conservation of Pro at position 97 and Gly at positions 98 and 100 in all clones expressing TCRBV13S1 suggest that these residues provide a framework for the tertiary structure of the CDR3 loop. Residues that contact MHC peptide are underlined. Amino acid numbering of TCR alpha and beta chains is as in reference 10. (Bottom) Comparison of CDR3 V beta amino acid sequences of Tax11-19-reactive CD8⁺ T-cell clones isolated in this study (groups I to V) and previously published (B7 and ID4) (13). Positions that are maintained in all clones are indicated by arrows.