CTL responses directed against accessory protein Vpr in HIV-1 clade B' infected Individuals

Aim To investigate HIV-1 specific CTL responses directed against accessory protein Vpr and its impact on virus replication in HIV-1 clade B' infected individuals.Methods 143 anti-retroviral therapy naive HIV-1 clade B' infected subjects were assessed for HIV-1 specific CTL responses with an IFN‐γ Elispot assay by using overlapping peptides covering Vpr protein consensus sequence.Association between CTL responses and viral load was analysed.Results 16.8% of the study subjects recognized at least one overlapping Vpr peptide.Vpr-responsive subjects had lower plasma viral loads than that of non-responsive subjects,the difference is statistically significant(P=0.0191);CTL recognition against OLP VPR-B-3 was correlated with low viral load suggesting that this peptide may contain amino acids critical for biological functions of Vpr protein.CTL responses against Vpr peptids in the study population were associated with Vpr sequence variation.Conclusion Vpr-specific CTL responses were correlated to the control of viral replication in the study population.Further characterization of the epitopes and their roles in pathogenesis of HIV-1 natural infection will benefit the design and testing of candidate vaccines.