HIV DNA Subspecies Persist in both Activated and Resting Memory CD4 + T Cells during Antiretroviral Therapy

ABSTRACT

The latent HIV reservoir is a major impediment to curing HIV infection. The contribution of CD4
+
T cell activation status to the establishment and maintenance of the latent reservoir was investigated by enumerating viral DNA components in a cohort of 12 individuals commencing antiretroviral therapy (ART) containing raltegravir, an integrase inhibitor. Prior to ART, the levels of total HIV DNA were similar across HLA-DR
+
and HLA-DR
−
(HLA-DR
±
) CD38
±
memory CD4
+
T cell phenotypes; episomal two-long terminal repeat (2-LTR) HIV DNA levels were higher in resting (HLA-DR
−
CD38
−
) cells, and this phenotype exhibited a significantly higher ratio of 2-LTR to integrated HIV DNA (
P
= 0.002). After 1 year of ART, there were no significant differences across each of the memory phenotypes of any HIV DNA component. The decay dynamics of integrated HIV DNA were slow within each subset, and integrated HIV DNA in the resting HLA-DR
−
CD38
−
subset per mm
3
of peripheral blood exhibited no significant decay (half-life of 25 years). Episomal 2-LTR HIV DNA decayed relative to integrated HIV DNA in resting cells with a half-life of 134 days. Surprisingly, from week 12 on, the decay rates of both total and episomal HIV DNA were lower in activated CD38
+
cells. By weeks 24 and 52, HIV RNA levels in plasma were most significantly correlated with the numbers of resting cells containing integrated HIV DNA. On the other hand, total HIV DNA levels in all subsets were significantly correlated with the numbers of HLA-DR
+
CD38
−
cells containing integrated HIV DNA. These results provide insights into the interrelatedness of cell activation and reservoir maintenance, with implications for the design of therapeutic strategies targeting HIV persistence.


IMPORTANCE
It is generally believed that HIV is not cleared by extensive antiretroviral therapy (ART) due to the difficulty in eradicating the latent reservoir in resting CD4
+
T cells. New therapies that attempt to activate this reservoir so that immune or viral cytopathic mechanisms can remove those infected cells are currently being investigated. However, results obtained in this research indicate that activation, at least on some level, already occurs within this reservoir. Furthermore, we are the first to describe the dynamics of different HIV DNA species in resting and activated memory CD4+ T cell subsets that point to the role different levels of activation play in maintaining the HIV reservoir.