Identification of the nonamer peptide from influenza A matrix protein and the role of pockets of HLA‐A2 in its recognition by cytotoxic T lymphocytes

Abstract

Influenza matrix peptide 58–66 is shown to be the optimal nonamer for binding to HLA-A2 and presentation to cytotoxic T lymphocytes (CTL). If titered out to 2 × 10⁻¹⁰ – 4 × 10⁻¹⁰M in CTL-mediated lysis assays and to 3 × 10⁻⁹M in an HLA-A2 assembly-stabilization assay in cell lysates. The peptide was shown to make probable contacts with its carboxy terminus close to residue 116 in the floor of the cleft of HLA-A2, close to the F pocket. The side chain of the amino-terminal amino acid was unimportant, but its free amino and carbonyl groups in the A pocket appeared important in optimizing peptide presentation. The B pocket probably accommodates the side chain of residue 2 (isoleucine) and was shown to be critical in peptide presentation.