Enhancing Anti-HIV Activity of duoCAR-T Cells by Combining TGF-ß Inhibition with IL-15 Stimulation 2405

Abstract Description Transforming growth factor-ß (TGF- ß) is a critical immunoregulatory cytokine that modulates immune homeostasis and suppresses T cell cytotoxic function. Elevated TGF- ß levels, often observed in people with HIV (PWH) even under antiretroviral therapy (ART), are associated with systemic inflammation and immune suppression. We previously developed a duoCAR-T cell therapy targeting HIV-1 gp120, combining two CARs: one recognizing a CD4-induced gp120 epitope and another includes a single domain from CD4, to both block HIV infection and target HIV-1-infected cells for elimination. We hypothesized that inhibiting TGF- ß while stimulating IL-15 signaling would increase duoCAR-T cell anti-HIV activity. To test this, we used a bifunctional protein, HCW9218 composed of TGF- ß RII and IL-15/IL-15a to simultaneously neutralize TGF- ß and stimulate NK and CD8 T cells. Control variants with inactive IL-15 or TGF- ß RII domains were included. Functional activity of the TGF- ß RII domains in HCW9218 was demonstrated by its inhibition of TGF- ß -induced SMAD2/3 phosphorylation, and of the IL-15 domain by its stimulation of STAT5 phosphorylation and duoCAR-T cell proliferation. duoCAR-T cells treated with HCW9218, but not control variants, showed increased cytotoxicity and HIV suppression under TGF- ß conditions. The HCW9218 cytokine-based scaffold holds promise as an adjunctive therapy to enhance CAR-T efficacy, offering potential for a more durable anti-HIV-1 immune response. Topic Categories Vaccines and Immunotherapy (VAC)