Identification, optimization and use of cryptic HLA-A24 epitopes for immunotherapy

摘要

A method for obtaining an HLA-A * 2402-restricted epitope capable of triggering an immune response against a HLA-A * 2402-restricted cryptic epitope of an antigen, comprising the steps of (i) selecting, in said antigen, of a peptide of 9 to 11 amino acids having a tyrosine at position 2 and one or more unfavorable amino acids at one or more secondary anchoring positions, selected from the group consisting of a proline at position 1 and a glutamic acid, an acid aspartic, a glycine, a histidine, a proline, a glutamine, an arginine and a lysine in position at the C-terminus; (ii) test, in HLA-A * 2402 transgenic mice, for the immunogenicity of the peptide selected in step (i); (iii) selection of said peptide if it fails to induce a specific immune response in HLA-A * 2402 (iv) transgenic mice for each natural epitope selected in step (iii), obtaining an optimized epitope increasing its immunogenicity, replacing the residue at the N-terminus of said epitope by an arginine or a lysine, and / or by substituting the residue at the C-terminus of said epitope for a leucine or an isoleucine or a phenylalanine, preferably for a leucine; (v) testing the immunogenicity of each optimized epitope obtained in step (iv), in HLA-A * 2402 transgenic mice, and selection of those that are immunogenic; (vi) for each epitope selected in step (v), testing to determine if the LTC generated against the optimized epitope also recognize its similar natural epitope, and selecting those for which the test is positive.