PD-1 blocking strategy for enhancing the anti-tumor effect of CAR T cells targeted CD105

These data showed that CD105 × PD-1 CAR T cells was specifically killing tumor cells in vitro and in vivo. Our findings may therefore provide a promising new strategy for the improvement of CAR T therapy for solid tumors.

we tested whether Increased PD-1 antibody secretion with CAR T cells targeted CD105 could promote in vitro proliferation, proinflammatory cytokine production and cytotoxicity,or not. For the in vivo experiments, we constructed a subcutaneously transplanted tumor model and placed it in NOD/SCID mice to verify the anti-tumor effect of this therapy.

Our data showed that the PD-1 antibody secreted by CD105 × PD-1 CAR T cells could specifically bind to the PD-1 receptor of T cells then blocked the PD-1/PD-L-1 signaling pathway, thus enhancing the activation and proliferation of CAR T cells. After incubation of CD105 × PD-1 CAR T cells with HepG2 as a hepatocellular carcinoma cell line expressing CD105, the results showed that CD105 × PD-1 CAR T cells increased the expression levels of CD69 and CD62L, enhanced the proliferation capacity of CAR T cells, and secreted more IL-2, TNF-α and IFN-γ than CD105 CAR T cells.