Recovery of Latent HIV-1 from Brain Tissue by Adoptive Cell Transfer in Virally Suppressed Humanized Mice

Defining the latent human immunodeficiency virus type 1 (HIV-1) burden in the human brain during progressive infection is limited by sample access. Human hematopoietic stem cells (hu-HSCs)-reconstituted humanized mice provide an opportunity for this study. The model mimics, in measure, HIV-1 pathophysiology, transmission, treatment, and elimination in an infected human host. However, to date, brain HIV-1 latency in hu-HSC mice during suppressive antiretroviral therapy (ART) was not studied. To address this need, hu-HSC mice were administered long acting (LA) ART 14 days after HIV-1 infection was established. Animals were maintained under suppressive ART for 3 months, at which time HIV-1 infection was detected at low levels in brain tissue by droplet digital polymerase chain reaction (ddPCR) test on DNA. Notably, adoptive transfer of cells acquired from the hu-HSC mouse brains and placed into naive hu-HSC mice demonstrated viral recovery. These proof-of-concept results demonstrate replication-competent HIV-1 reservoir can be established in hu-HSC mouse brains that persists during long-term ART treatment. Hu-HSC mice-based mouse viral outgrowth assay (hu-MVOA) serves as a sensitive tool to interrogate latent HIV-1 brain reservoirs.