DEFINITION OF AMINO-ACID-RESIDUES ON THE EPITOPE RESPONSIBLE FOR RECOGNITION BY INFLUENZA-A VIRUS H1-SPECIFIC, H2-SPECIFIC, AND H1-CROSS-REACTIVE AND H2-CROSS-REACTIVE MURINE CYTOTOXIC T-LYMPHOCYTE CLONES

We defined the epitopes recognized by three influenza A virus-specific , H-2K(d)-restricted CD8(+) cytotoxic T-lymphocyte (CTL) clones: III-s pecific clone A-it, HZ-specific clone F-l, and H1- and NZ-cross-reacti ve clone B7-B7, The A-12 and B7-B7 clones recognized the same peptide, which comprises amino acids 533 to 541 (IYSTVASSL) of A/PR/8 hemagglu tinin (HA). The F-4 and B7-B7 clones both recognized the peptide which comprise amino acids 529 to 537 (IYATVAGSL) of A/Jap HA, Amino acids 533 to 541 of A/PR/8 HA are compatible with amino acids 529 to 537 of A/Jap HA. Amino acid S at positions 3 and 7 was responsible for-recogn ition by Hi-specific clone A-12, while amino acid G at position 7 was responsible for recognition by H2-specific clone F-4. Two conserved am ino acids, T at position 4 and A at position 6, were responsible for r ecognition by H1-, and H2-cross-reactive clone B7-B7, These results in dicate that a single nine-amino-acid region is recognized by HA-specif ic CTL clones of three different subtype specificities and that the am ino acids responsible for the recognition by the CTL clones are differ ent.