Initial HIV-1 Antigen-Specific CD8 + T Cells in Acute HIV-1 Infection Inhibit Transmitted/Founder Virus Replication

Abstract

CD8-mediated virus inhibition can be detected in HIV-1-positive subjects who naturally control virus replication. Characterizing the inhibitory function of CD8 + T cells during acute HIV-1 infection (AHI) can elucidate the nature of the CD8 + responses that can be rapidly elicited and that contribute to virus control. We examined the timing and HIV-1 antigen specificity of antiviral CD8 + T cells during AHI. Autologous and heterologous CD8 + T cell antiviral functions were assessed longitudinally during AHI in five donors from the CHAVI 001 cohort using a CD8 + T cell-mediated virus inhibition assay (CD8 VIA) and transmitted/founder (T/F) viruses. Potent CD8 + antiviral responses against heterologous T/F viruses appeared during AHI at the first time point sampled in each of the 5 donors (Fiebig stages 1/2 to 5). Inhibition of an autologous T/F virus was durable to 48 weeks; however, inhibition of heterologous responses declined concurrent with the resolution of viremia. HIV-1 viruses from 6 months postinfection were more resistant to CD8 + -mediated virus inhibition than cognate T/F viruses, demonstrating that the virus escapes early from CD8 + T cell-mediated inhibition of virus replication. CD8 + T cell antigen-specific subsets mediated inhibition of T/F virus replication via soluble components, and these soluble responses were stimulated by peptide pools that include epitopes that were shown to drive HIV-1 escape during AHI. These data provide insights into the mechanisms of CD8-mediated virus inhibition and suggest that functional analyses will be important for determining whether similar antigen-specific virus inhibition can be induced by T cell-directed vaccine strategies.