Myeloid Dendritic Cells Induce HIV-1 Latency in Non-Proliferating CD4+ T Cells

Latently infected resting CD4+ T cells are a major barrier to HIV cure. Understanding how latency is established, maintained and reversed is critical to identifying novel strategies to eliminate latently infected cells. We demonstrate here that co-culture of resting CD4+ T cells and syngeneic myeloid dendritic cells (mDC) can dramatically increase the frequency of HIV DNA integration and latent HIV infection in non-proliferating memory, but not naïve, CD4+ T cells. Gene expression in non-proliferating CD4+ T cells, enriched for latent infection, showed significant changes in the expression of genes involved in cellular activation and interferon regulated pathways, including the down-regulation of genes controlling both NF-κB and cell cycle. We conclude that mDC play a key role in the establishment of HIV latency in resting memory CD4+ T cells, which is predominantly mediated through signalling during DC-T cell contact. Resting (CD69-CD25-HLA-DR-) CD4+ T cells were enriched from the blood of 4 normal donors by magnetic bead depletion and labelled with the proliferation dye SNARF. SNARFhiEGFP- CD4+ T cells cultured with (+DC) or without syngeneic bulk DC (lin-HLA-DR+), in the presence (HIV T) or absence (Mock T) of HIV, were sorted 5 days following infection with NL(AD8)-nef/EGFP (MOI 5).Culture media was supplemented with 10ng/mL of IL-7. The gene expression profile of the 4 cell populations: 1. HIV T (+DC); 2. Mock T (+DC); 3. HIV T; and 4. Mock T, was determined.