CD8+T-cell response to mutated HLA-B*35-restricted Gag HY9 and HA9 epitopes from HIV-1 variants from Medellin, Colombia

The HLA-B*35 alleles have been associated with a slow or rapid progression of HIV-1 infection. However, the mechanisms related to HIV-1 progression have yet to be entirely understood. Several reports indicate that the binding affinity between the HLA-I molecule and peptides could be associated with an increased CD8+ T-cell response. Novel HLA-B*35-restricted mutated variants have been described from HSNQVSQNY (HY9) and HPVHAGPIA (HA9) epitopes. Bioinformatic analysis has indicated that these mutated epitopes show low and high binding affinity towards HLA-B*35, respectively. However, the polyfunctionality of CD8+ T-cells stimulated with these mutated and wild-type epitopes has yet to be reported. The results suggest that the low-binding affinity H124 N/S125 N/N126S mutated peptide in the HY9 epitope induced a lower percentage of CD107a+CD8+ T-cells than the wild-type epitope. Instead, the high-binding affinity peptides I223V and I223A in the HA9 epitope induced a significantly higher frequency of polyfunctional CD8+ T-cells. Also, a higher proportion of CD8+ T-cells with two functions, with Granzyme B+ Perforin+ being the predominant profile, was observed after stimulation with mutated peptides associated with high binding affinity in the HA9 epitope. These results suggest that the high-affinity mutated peptides induced a more polyfunctional CD8+ T-cell response, which could be related to the control of viral replication.