B. J. Van den Eynde, H. Mazarguil, B. Lethé
Nov 1, 1994
Citations
2
Influential Citations
36
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Journal
European Journal of Immunology
Abstract
Mouse mastocytoma P815 expresses tumor antigens P815A and P815B encoded by a single gene called P1A and carried by a single peptide named P1A 35–43 (NH2‐Leu‐Pro‐Tyr‐Leu‐Gly‐Trp‐Leu‐Val‐Phe‐COOH). P1A 35–43 is presented to anti‐P815A and anti‐P815B cytotoxic T lymphocytes (CTL) by major histo‐compatibility complex (MHC) H‐2Ld molecules. In order to determine the individual role played by each amino acid residue of P1A 35‐43 in binding to H‐2Ld and in recognition by anti‐A and anti‐B T cell receptors (TcR), a series of P1A 35‐43 peptides substituted by alanine at single positions was synthesized and tested for binding to H‐2Ld and for CTL recognition. Binding to H‐2Ld was estimated by measuring the ability of the peptide to up‐regulate cell surface expression of H‐2Ld. We found that three residues were important for interaction of P1A 35‐43 with H‐2Ld. Two of them, Pro at position 2 and Phe at position 9 were consistent with the described H‐2Ld binding motif. A third residue, Trp at position 6, was also required for effective MHC binding of the tumor antigen. CTL sensitization assays showed that alanine substitution at position 7 (Leu) or at position 8 (Val) dramatically affected peptide recognition by anti‐A CTL while positions 3 (Tyr) and 4 (Leu) were critical for recognition by anti‐B CTL. We conclude that Pro2, Trp6 and Phe9 constitute the anchor residues of P1A 35‐43 to H‐2Ld, whereas the dipeptidyl sequences Tyr3‐Leu4 and Leu7‐Val8 form the core epitopes recognized by the TcR of anti‐P815B and anti‐P815A CTL, respectively.