AbstractWe have identified two epitopes for Epstein‐Barr virus specific cytotoxic T lymphocytes (CTL) restricted by the common allele HLA‐B7. They are EBNA 3C 881–9 (QPRAPIRPI) and EBNA 3A 379–387 (RPPIFIRRL). The epitopes conform well to the recently described motif for HLA‐B7‐binding peptides (Huckzo et al.,J. Immunol.1993.151:2572). Titration of the peptides in CTL assays and detergent lysate binding assays revealed that extending the peptides at either the N or C terminus did not reduce their affinity for HLA‐B7. This behavior contrasted with HLA‐B51, which binds peptides with a similar motif to B7, and has identical amino acid residues at sites expected to form the “F” pocket of the peptide‐binding groove. HLA‐B51 also bound the peptide EBNA 3C 881–9, but was unable to bind peptides e