Mechanisms of HIV non-progression; robust and sustained CD4+ T-cell proliferative responses to p24 antigen correlate with control of viraemia and lack of disease progression after long-term transfusion-acquired HIV-1 infection

Dyer, Wayne B; Zaunders, John J; Yuan, Fang Fang; Wang, Bin; Learmont, Jennifer C; Geczy, Andrew F; Saksena, Nitin K; McPhee, Dale A; Gorry, Paul R; Sullivan, John S

Host and viral genetic factors may have played a role in delaying disease progression into the second decade of infection in these 13 individuals, but this study also demonstrates the importance of host immune responses in sustaining this non-progressive disease course into and beyond the second decade of infection. Immune status and activity of HIV-specific CD4 T cells (proliferation) and CD8 T cells (IFN-γ response) is shown for the current non-progressors ( Figure 1 ) compared with those that lost their non-progressor status or died ( Figure 2 ). Antiviral CTL responses were variable during the second decade of HIV infection, and did not always correlate with viremia for members of these cohorts. Strong Gag-specific CTL were detected in the Cohort 2 non-progressors (C13, C53, C122, and C105 before ART), but the predominant CTL response in the SBBC members was against Pol antigens. These CTL appeared to be equally effective in containing viral replication, whether Gag-specific as demonstrated in earlier time points in C122, or Pol-specific in C18 ( Figure 2 ).