Blocking CD30 on CD19 CAR T cells augments their functional capacities against B-cell leukemia/lymphoma

Adoptive therapy with CD19 chimeric antigen receptor (CAR) T cells is effective against B-cell malignancies; however, T-cell activation rapidly declines, increasing the risk of early leukemia relapses. To augment CD19 CAR T-cell functionality, we interfered with the physiological control of T-cell activation by a CAR that prevents the T cell's inherent CD30-CD30L interaction. Redirected by the bispecific CD30/CD19 CAR, T cells were superior to canonical CD19 CAR T cells in eliminating CD30^-CD19⁺ cells. Also, CD19⁺ B acute leukemia cells from patients were more efficiently eliminated by the CD30/CD19 CAR T cells in vitro than by CD19 CAR T cells. For simultaneous CD30 blocking and CD19 targeting, the scFv order CD30/CD19 in the CAR was superior to CD19/CD30 in forming an optimal synaptic gap. The extended T-cell functionality was not due to binding of any two targets since the bispecific CD20/CD19 CAR was less efficient. Preventing the CD30-CD30L interaction results in reduced TRAF2 levels, increased IκBα, late partial feedback Ser529-p65 phosphorylation, a moderate pSTAT3 elevation, enhanced granzyme B/IFN-γ production, and a dampened Th2 polarization, shifting CD8+ CAR T cells from an immunosuppressive to a more cytotoxic phenotype. Our data demonstrate a strategy in augmenting the efficacy of CD19 CAR T cells against B-cell malignancies by concomitant blocking the T cell's own CD30-CD30L interaction.