Myeloid dendritic cells induce HIV-1 latency in non-proliferating CD4+ T cells

Dendritic cell-induced activation of latent HIV-1 provirus in actively proliferating primary T lymphocytes

HIV-1 latency remains a formidable barrier towards virus eradication as therapeutic attempts to purge these reservoirs are so far unsuccessful. The pool of transcriptionally silent proviruses is established early in infection and persists for a lifetime, even when viral loads are suppressed below detection levels using anti-retroviral therapy. Upon therapy interruption the reservoir can re-establish systemic infection. Different cellular reservoirs that harbor latent provirus have been described. In this study we demonstrate that HIV-1 can also establish a silent integration in actively proliferating primary T lymphocytes. Co-culturing of these proliferating T lymphocytes with dendritic cells (DCs) activated the provirus from latency. Activation did not involve DC-mediated C-type lectin DC-SIGN signaling or TCR-stimulation but was mediated by DC-secreted component(s) and cell-cell interaction between DC and T lymphocyte that could be inhibited by blocking ICAM-1 dependent adhesion. These results imply that circulating DCs could purge HIV-1 from latency and re-initiate virus replication. Moreover, our data show that viral latency can be established early after infection and supports the idea that actively proliferating T lymphocytes with an effector phenotype contribute to the latent viral reservoir. Unraveling this physiologically relevant purging mechanism could provide useful information for the development of new therapeutic strategies that aim at the eradication of HIV-1 reservoirs.

HIV reservoirs and strategies for eradication

Combination antiretroviral therapy (cART) has led to a reduction in morbidity and mortality in HIV-infected patients but therapy is lifelong and there is no cure for HIV. The major barriers to cure include HIV latency, which has been identified in different T-cell subsets, as well as persistence of HIV in anatomical reservoirs. We review recent developments in our understanding of the major reservoirs of HIV in patients on cART as well as how latency is established and maintained in T cells. Finally, we review the scientific rationale of and clinical experience with pharmacotherapeutic strategies aimed at eliminating latently infected cells.

Workshop report: “Towards a Cure: HIV Reservoirs and Strategies to Control Them”

On 16 and 17 July 2010, immediately prior to the XVIII International AIDS Conference in Vienna, Austria, the International AIDS Society held a workshop on the important topic of moving beyond antiretroviral therapy and addressing HIV persistence. “Towards a Cure: HIV Reservoirs and Strategies to Control Them” was chaired by Nobel laureate Françoise Barré-Sinoussi and co-sponsored by the French National Agency for Research on AIDS and Viral Hepatitis, Bundesministerium für Wissenschaft und Forschung, the National Institutes of Health, Sidaction and the Treatment Action Group. This article gives an overview of the findings presented at the workshop; complete abstracts are included in this supplement to the Journal of the International AIDS Society.