Five CTL clones specific for the A
*02 restricted peptide epitope of TAA Mage-3, designated M3-271, were studied. All these clones were able to recognize peptide M3-271 when presented by BLCLs expressing A
*0201, A
*0206 and A
*0209. In contrast, peptide pulsed BLCLs carrying A
*0202 or A
*0205 were recognized by none of the clones. As determined by
in vitro peptide binding studies, this was not due to a lack of binding ability of peptide M3-271 to these two A
*02 subtypes. Finally, three or two of the five clones analyzed were able to recognize peptide pulsed BLCLs carrying A
*0204 or A
*0207, respectively.
A CTL line specific for the dominant, A*02 restricted epitope of TAA Melan-A/MART-1, designated MT27-35, was able to lyse peptide pulsed BLCLs expressing all A*02 subtypes analyzed except for A*0207. This may be due to a lack of binding activity of MT27-35 to A*0207 since others have shown that polyalanine peptides carrying the same P2/P9 anchor residues as MT27-35 were unable to bind to A*0207 while they could readily bind to the other A*02 subtypes tested in this study.