溶瘤流感病毒联合PD-1抗体增强对肝癌的抗肿瘤活性研究

Antitumor activity of recombinant oncolytic virus combined with PD-1 antibody against hepatocellular carcinoma

目的探讨重组溶瘤流感病毒联合免疫检查点抑制剂PD-1抗体治疗肝癌的效果。方法全面鉴定重组溶瘤流感病毒delNS1-GM-CSF,通过血凝实验、TCID50测定重组溶瘤流感病毒滴度;电镜观察病毒形态和病毒粒子大小及分布;利用H22肝癌荷瘤Balb/c小鼠模型,研究delNS1-GM-CSF联合PD-1抗体对肿瘤杀伤和T细胞浸润的影响。结果重组溶瘤流感病毒delNS1-GM-CSF的血凝效价2^(8)~2^(9)。肝癌荷瘤Balb/c小鼠模型表明,重组溶瘤流感病毒delNS1-GM-CSF联合PD-1治疗组抑制肿瘤生长的能力显著强于单病毒组或单抗体组(P<0.01)。重组溶瘤流感病毒delNS1-GM-CSF和PD-1联合治疗组具有较强的杀伤肿瘤效果(P<0.01)。免疫组化和H&E染色结果表明,联合治疗组小鼠肿瘤中T淋巴细胞较丰富,肿瘤坏死严重。结论重组溶瘤流感病毒delNS1-GM-CSF联合PD-1抗体治疗可显著抑制肝癌细胞生长,增强体内抗肿瘤免疫应答。

This study was designed to investigate the efficacy of recombinant oncolytic virus delNS1-GM-CSF combined with immune checkpoint inhibitor PD-1 in the treatment of hepatocellular carcinoma.Recombinant oncolytic virus(delNS1-GM-CSF)was identified and the titer of recombinant oncolytic virus(delNS1-GM-CSF)was determined with hemagglutination test and TCID50.The morphology and particle size distribution of the virus were observed under electron microscope;the effect of delNS1-GM-CSF combined with PD-1 antibody on tumor killing and T cell infiltration were investigated by using a subcutaneous tumor bearing mouse model of H22 liver cancer cells.Data showed that the hemagglutination titer of delNS1-GM-CSF was 2^(8)-2^(9).In vivo experiments showed that delNS1-GM-CSF and PD-1 combined treatment group had stronger tumor growth inhibition ability than single virus or single antibody group(P<0.01).It shows that the combined treat with delNS1-GM-CSF and PD-1 antibody has strong antitumor activity(P<0.01).Immunohistochemistry and HE staining showed that T lymphocytes were abundant in the tumor tissue of delNS1-GM-CSF combined PD-1 antibody treated-mice,and the tumor necrosis was severe.Taken together,combined treatment with delNS1-GM-CSF and PD-1 antibody can significantly inhibit the growth of hepatocellular carcinoma cells and enhance the anti-tumor immune response in vivo.