Efficacious early antiviral activity of HIV Gag- and Pol-specific HLA-B 2705-restricted CD8+ T cells.
Payne RP., Kløverpris H., Sacha JB., Brumme Z., Brumme C., Buus S., Sims S., Hickling S., Riddell L., Chen F., Luzzi G., Edwards A., Phillips R., Prado JG., Goulder PJ.
The association between HLA-B 2705 and the immune control of human immunodeficiency virus type 1 (HIV-1) has previously been linked to the targeting of the HLA-B 2705-restricted Gag epitope KRWIILGLNK (KK10) by CD8(+) T cells. In order to better define the mechanisms of the HLA-B 2705 immune control of HIV, we first characterized the CD8(+) T-cell responses of nine highly active antiretroviral therapy (HAART)-naïve B 2705-positive subjects. Unexpectedly, we observed a strong response to an HLA-B 2705-restricted Pol epitope, KRKGGIGGY (KY9), in 8/9 subjects. The magnitude of the KY9 response was only marginally lower than that of the KK10-specific response (median, 695 versus 867 spot-forming cells [SFC]/million peripheral blood mononuclear cells [PBMCs]; not significant [NS]), and viral escape mutants were observed in both KY9 and KK10, resulting from selection pressure driven by the respective CD8(+) T-cell response. By comparing inhibitions of viral replication by CD8(+) T cells specific for the Gag KK10, Pol KY9, and Vpr VL9 HLA-B 2705-restricted epitopes, we observed a consistent hierarchy of antiviral efficacy (Gag KK10 > Pol KY9 > Vpr VL9). This hierarchy was associated with early recognition of HIV-1-infected cells, within 6 h of infection, by KK10- and KY9-specific CD8(+) T cells but not until 18 h postinfection by VL9-specific CD8(+) T cells. There was no association between antiviral efficacy and proliferative capacity, cytotoxicity, polyfunctionality, or T-cell receptor (TCR) avidity. These data are consistent with previous studies indicating an important role for the B 2705-Gag KK10 response in the control of HIV but also suggest a previously unrecognized role played by the subdominant Pol-specific KY9 response in HLA-B 2705-mediated control of HIV and that the recognition of HIV-infected cells by CD8(+) T cells early in the viral life cycle may be important for viral containment in HIV-infected individuals.