目的: 探讨奥沙利铂（oxaliplatin, OXA）联合PD-1 抗体对结肠癌的抗肿瘤作用。方法：选用结肠癌细胞系HCT-116和HT-29，用流式细胞术检测细胞中PD-L1 的表达。采用T细胞共培养的方法检测OXA预处理HCT-116 细胞联合PD-1 抗体作用后细胞因子分泌及CD4/CD8 亚型变化。建立BALB/c 小鼠的结肠癌细胞CT26 移植瘤模型，用OXA联合PD-1 抗体治疗，评估其抗肿瘤活性；同时采用CD8 抗体清除小鼠CD8+T细胞，评估CD8+T细胞在OXA抗肿瘤中的作用。结果：OXA能够显著上调结肠癌细胞表面PD-L1的表达。OXA预处理后的结肠癌HCT-116 细胞和T细胞共培养后，与单纯培养的T细胞相比，能降低其培养上清中IL-2、IFN-γ和TNF的水平（均P<0.05）及体系中CD4+记忆性T细胞和CD8+TEMRA比率（P<0.05）、增加CD4（+ P>0.05）和CD8+（P<0.05）初始T细胞比率；联合PD-1 抗体后，与OXA预处理的HCT-116 和T细胞共培养组相比，T细胞培养上清中IFN-γ 和IL-10含量（P<0.05）以及CD8+ TCM和TEMRA比率增加（P>0.05）。体内抑瘤实验表明，OXA联合PD-1 抗体可以增强其抗肿瘤活性，抑瘤率显著高于单用OXA组和αPD-1 组（58.2% vs 25.6% 、29.1%，均P<0.05）；清除CD8+ T细胞后，OXA的抗肿瘤活性由68.4%下降到46.2%（P<0.05）。结论：OXA联合PD-1抗体具有联合增效的作用，同时CD8+T细胞在OXA的抗肿瘤活性中具有重要作用。

Objective: To explore the anti-tumor effects of oxaliplatin (OXA) combined with PD-1 antibody on colon cancer. Methods:Flow cytometry was used to detect the expression of PD-L1 in colon cancer cell lines HCT-116 and HT-29. Co-culture method was used to detect the secretion of cytokines and the changes of CD4/CD8 subsets in T-cells that co-cultured with HCT-116 cells, which were pretreated with OXA in combination with/without PD-1 antibody; The CT26 transplanted tumor model of colon cancer in BALB/c mice was established and treated with the combination of OXA and PD-1 to evaluate their anti-tumor efficacy. Meanwhile, CD8 antibody was used to scavenge CD8+ T cells in mice, and to evaluate the role of CD8+ T cells in the anti-tumor effect of OXA in vivo. Results:OXA could significantly increase the expression of PD-L1 on the surface of colon cancer cells. Compared with pure T-cells, the T cells co-cultured with colon cancer HCT-116 cells that pre-treated by OXA, exhibited significantly reduced IL-2, IFN-γ and TNF levels (all P<0.05) in its culture supernatant and decreased ratio of CD4+ memory T cell / CD8+TEMER (P<0.05), whereas there was increased cell proportion of the CD4+ (P>0.05) and CD8+ (P<0.05) na?ve T cells. After co-treated with PD-1 antibody, compared with the single treatment of OXA, IFN-γ and IL-10 content (P<0.05) in culture supernatant and the subsets of CD8+ TCM and TEMRA ratio (P>0.05) were increased. In vivo experiments showed that OXA combined with PD-1 antibody could enhance its anti-tumor activity, the tumor suppression rates were 25.6% (OXA) and 29.1% (αPD-1), respectively, however, the rate of tumor inhibition was increased to 58.2% when combined (P<0.05, compared to OXA or αPD-1 group). After scavenging CD8+ T cells in mice, the antitumor activity of OXA dropped from 68.4% to 46.2% (P<0.05). Conclusion: OXA combined with PD-1 antibody had synergistic anti-tumor effect, and CD8+ T cells played an important role in the antitumor activity of OXA.

国家自然科学青年基金资助项目（No. 81602709；81872361）；河南省高校重点科研资助项目No.15A320063, No.16A310022）；河南省骨干青年教师培养计划（No.2016GGJS-105）