Generation of HIV- and CD19-Specific TSCM CAR-T Cells by a Novel Cytokine-Based Scaffold 2319

Description While activation of T-cells with anti-CD3/CD28 (aCD3/28) enables efficient lentiviral transduction to generate CAR-Ts, these CAR-Ts are more differentiated with reduced in vivo persistence. We hypothesized that T-cell treatment with scaffold-linked IL7, IL15 and IL21 (HCW9206) would enable production of CAR-Ts uniquely enriched for a T-stem-like phenotype (CD45RO-CCR7+CD95+, TSCM) with increased in vivo functional persistence. Anti-HIV-duoCAR-Ts or CD19-CAR-Ts were generated from CD3 T-cells purified from HIV-seronegative and seropositive donors treated with HCW9206 or aCD3/28. Compared to aCD3/28-generated CAR-Ts, HCW9206-generated CAR-Ts were significantly enriched for TSCM (> 53%) and displayed potent in vitro HIV-1 viral suppression or CD19+ tumor cytotoxicity, and inflammatory TNFα and IFNγ production. To evaluate in vivo CAR-T function and persistence, NSG mice were intravenously injected with HCW9206 or aCD3/28 CD19-CAR-Ts one day following CD19+ NALM6-Luc cell engraftment (4:1 E:T). While HCW9206 and aCD3/28 CAR-Ts had comparable potent elimination of NALM6-Luc cells after the first challenge, only HCW9206 CAR-Ts elicited a recall response after re-challenge with NALM6-Luc, which was associated with enhanced HCW9206 CAR-T cell expansion and NALM6-Luc tumor suppression. Our results demonstrate that treatment with HCW9206 generates CAR-TSCM that improves long-term in vivo functional persistence of CAR-Ts with the potential to provide sustained HIV and cancer remission.