Lymph node dendritic cells harbor inducible replication-competent HIV despite years of suppressive ART

The comprehensive characterization and quantification of the HIV tissue reservoirs is required to design appropriate therapeutic intervention(s) to achieve a cure. While pioneering studies demonstrated that HIV replication and spreading mainly occur in lymphoid tissues, the identification of specific cell subsets harboring replication competent virus in lymphoid tissues has long been neglected. In this context, we and others have recently shown that gut memory CD4 T cells, lymph node T follicular helper (Tfh) cells and tissue macrophages represent major HIV/SIV tissue reservoirs. Notably, Tfh cell differentiation is a multi-stage process that requires long-lasting interactions with lymph node (LN) dendritic cells (DCs) and pre-germinal center B cells in a specific cytokine/chemokine microenvironment. Lymph node DCs are endowed with an exceptional T-cell stimulatory potential and can either migrate from the periphery to the draining lymph node (migratory DCs) or locate in the LN for their entire life span (resident DCs). On the basis of these unique properties, long-term persistence of LN DCs infected with replication competent virus may represent the initial trigger of viral rebound post ART interruption and may therefore represent a major obstacle to HIV cure. We demonstrate that LN migratory DCs are infected with replication competent virus and persist despite suppressive ART. In addition, we identified the mechanisms associated with i) LN DC susceptibility to HIV infection and ii) long term persistence of HIV-infected LN DCs i.e. proliferation of infected cells in tissue sanctuaries. 3 anti-retroviral therapy treated HIV-infected individuals