BACH2 Controls Seeding and Establishment of Long-Lived HIV-1 Reservoir in CD4+ T cells

Despite antiretroviral therapy, HIV mainly persists in memory CD4+ T cells in people living with HIV. Most long-lived viral reservoir cells are infected near the time of therapy initiation. A better understanding of the early events in reservoir seeding presents opportunities for preventing latent reservoir formation. Here, we demonstrated that CD4+ T cells expressing CCR5, permissive to HIV-1 infection, are effector or terminally differentiated cells. BACH2 is expressed by a small subset of CCR5+ cells and reverses their terminal differentiation. BACH2-mediated memory differentiation is impeded due to heightened inflammation before treatment initiation. Mice with a BACH2 knockout human immune system has a reduced frequency of HIV-1 reservoir cells and do not experience virus rebound after treatment discontinuation. Our study reveals that BACH2 is essential to the seeding of long-lived HIV-1 reservoir and demonstrates the potential of targeting BACH2 at the time of treatment initiation to eliminate HIV-1 reservoirs in T cells. Overall design: Human primary CD4+ T cells were purified by negative selection with MojoSort™ Human CD4 T Cell Isolation Kit (Biolegend). Purified CD4+ T cells (106 cells/mL) were cultured in RPMI 1640 medium supplemented with 10% FCS, penicillin (100 unit/mL) and streptomycin (100 µg/mL). To generate activated cells, CD4+ T cells were stimulated with plate-bound anti-CD3 and anti-CD28 antibodies at 1µg/mL (BioLegend) for 3 days in the presence of 20 ng/mL IL-2. Stimulated CD4+ T cells were cultured with 20 ng/mL IL-2 for 6 days. CCR5+ and CCR5- CD4+ T cells were sorted followed by bulk RNA-Seq experiments.