PD-1抑制剂Nivolumab对CD19嵌合抗原受体T细胞体外增殖和杀伤活性的影响

OBJECTIVE: To Evaluation the effect of PD-1 inhibitor Nivolumab on the proliferation and cytotoxicity of anti-CD19 chimeric antigen receptor T cells (CD19-CAR-T) in vitro. METHODS: Five patients with high PD-1 expression in peripheral blood and five healthy volunteers were selected. These peripheral blood mononuclear cells were used as the source of T cells to prepare CD19-CAR-T cells. Different doses (72, 36, 18 µg/ml) of Nivolumab was added on day 8 to the culture medium. Patient T cells incubated with 72 µg/ml Nivolumab and CD19-CAR-T cells of healthy volunteers were used as controls. CCK-8, lactate dehydrogenase (LDH) cytotoxicity assay and ELASA were used to detect the proliferation capacity, the specific cytotoxicity and the inflammatory factor secretion. RESULTS: ①T cells from patients with high expression of PD-1 as the source of CD19-CAR-T cells did not affect transfection rate compared with that of healthy volunteers [(32.80±7.22)% vs (35.10±5.84)%, t=−0.554, P=0.593]. ②Incubation of CD19-CAR-T cells with 72 µg/ml Nivolumab did not affect CD19-CAR-T cell proliferation, but its cytotoxicity was significantly higher than that of CD19-CAR-T cells alone or patients' T cells +72 µg/ml Nivolumab (all P<0.001), there was no significant difference in the killing activity between the 72 µg/ml and 36 µg/ml Nivolumab treated CD19-CAR-T cells on Pfeiffer cells (P=0.281, 0.267, respectively), and they were all higher than those of 18 µg/ml Nivolumab treated CD19-CAR-T cells (all P<0.001). ③Different doses of PD-1 inhibitor Nivolumab combined with CD19-CAR-T cells does not affect the secretion of IFN-γ and IFN-α (all P>0.05). CONCLUSION: Combination of 36 µg/ml PD-1 inhibitor and CD19-CAR-T cells could reduce the drug toxicity and enhance the cytotoxicity.