HCV NS5B (2594-2602) HLA-A*02:01 ALYDVVTKL

T cell epitopes are presented on the surface of antigen-presenting cells by MHC molecules. T cell epitopes presented by MHC class I molecules are typically peptides between 8 and 11 amino acids in length and exhibiting MHC-specific sequence motifs

Results of B. Vali et al. We identified a relatively high degree of amino acid sequence similarity between HLA-A2-restricted epitopes HIV (HXB2) gag: 77-85 (SLYNTVATL: SL9) and HCV (H77) NS5b:2594-2602 (ALYDVVSKL: AL9). Of the screened HIV-infected individuals, 5 subjects showed significant response to both peptides. PBMCs from these individuals were used for tetramer analysis. Among the examined responders, three individuals showed CD8+ T-cells distinctly double-stained for both tetramers. Flow cytometry was conducted for expression analysis of IFN-g and the degranulation marker CD107a on PBMCs stained with SL9 tetramer and stimulated with either SL9 or AL9 peptides ... .

Conclusions: The preliminary findings of the group indicate a potential T-cell cross-recognition between HIV derived HLA-A2 restricted SLYNTVATL and HCV derived HLA-A2 restricted ALYDVVSKL epitopes. This degeneracy of HIV-specific T-cells may play a role in the underlying immunological mechanisms related to pathological profile of HCV/HIV co-infection and variable clinical outcomes influenced by different CD8 T-cell repertoire.