Abstract: Objective To introduce the aminoacid substitution for HP V16E7_49-57(HLA-A2-restricted CTL epitope) and to identify the novel epitopes.Methods Quantitative method was used to evaluate the affinity of the substituted peptides.To determine the peptide candidates to be synthesized and identified,the molecular models of the HLA-A2-peptide complex and CTL epitope candidates bound to the HLA-A2 molecule were established by computer molecular modeling.Peptides were synthesized and purified with standard Fmoc assay,lactate dehydrogen ase (LDH) release assay was used to determine their abilities of inducing the generation of specific CTLs. Results Modified peptidesmet the requirements of H LA-A2-restricted CTL epitopes.Peptide RLHYNIVTF had the abilitiy of inducing the generation of specific CTLs. Conclusions Compared with HPV17E7_49-57 the modified peptide RLHYNIVTF has a higher antigenicity and affinity to HLA-A2.So,peptide RLHYNIVTF maybe used as one of the HLA-A2-restricted candidate epitopes,instead of HPV17E7_49-57,for peptide vaccine in the treatment of HPV infection.

Key words: Papillomavirus, human, Epitopes, T-lymphocyte, Amino acid motifs, E7 antigen