Multiplex engineering of rhesus macaque NK cells enhances homing to sites of HIV replication in B cell follicles.

One barrier to developing an HIV-1 cure is viral reservoirs persisting within B cell follicles of lymphatic tissues, partly due to failure of HIV-specific cytotoxic cells to express the follicular-homing receptor CXCR5. Our group explores CAR cell therapies which also express CXCR5 as a potential cure strategy for HIV. Although previous studies have mostly explored CAR T cell therapies, CAR NK cells may be an attractive alternative as they can be used in allogeneic settings and are naturally cytotoxic towards HIV-infected cells. Here, we developed a novel and innovative multiplex engineering method for rhesus macaque NK cells to create virus-specific CAR NK cells multiplexed (MP) with CAR/CXCR5/IL-15/PD-1 KO/transient-CCR7. We first evaluated MP NK cells in vitro for functionality. MP NK cells were then infused into one chronically SIV-infected rhesus macaque to observe tolerance and localization of therapeutic cells. Finally, we performed a larger primate study in which SIV-infected rhesus macaques were infused with two doses of MP NK cells to study long-term localization, safety, and efficacy. In vitro, MP NK cells were expanded to clinically relevant numbers, migrated to chemokine signaling, and secreted cytotoxic cytokines in response to SIV-Env-expressing cells. In the preliminary rhesus macaque study, the therapy caused no adverse reactions, and CAR+ NK cells localized to sites of SIV replication within the spleen and lymph nodes. In the larger primate study, two doses of MP NK cells at 1.2 x 108 cells/kg were safe and increased the levels of NK cells and CAR+ NK cells found within lymphatic tissues. Importantly, the CAR+ NK cells detected in lymph nodes were predominantly CCR7+, demonstrating the importance of CCR7 and CXCR5 in combination for migration to SIV viral reservoirs in follicles of lymphatic tissues. This study is the first to demonstrate this type of complexity and combination of engineering techniques in NK cells. With further optimization, these techniques could lead to the development of novel NK cell therapies to treat HIV and other diseases.