摘要
为了研究表达小鼠抗PD-1 抗体(VT1093M)的溶瘤病毒对结肠癌腹腔移植瘤模型的抗肿瘤作用,利用BALB/c小鼠成瘤的小鼠结肠癌CT26-luc细胞株建立了结肠癌腹腔移植瘤模型.接种后第8 天进行分组,设置生理盐水(normal saline,NS)组、病毒VT09X组和VT1093M组,每组5 只,注射剂量为2.5×107 pfu/250 μL,NS注射250 μL,每隔一天注射一次,共注射5 次.末次注射后6d,脱颈处死小鼠,提取外周血中CD45+细胞和腹水细胞,进行体外杀伤实验.治疗组初次出现荧光消失后第 13 天,进行再挑战实验.结果表明,造模实验确定最佳接种条件为200 μL的2.5×106个/mL细胞悬液;药效实验中,VT09X组和VT1093M组较NS组具有明显的肿瘤抑制效果,VT1093M组治疗期间出现肿瘤消失情况,较VT09X组抑瘤效果明显,但差异无统计学意义;再挑战实验中,VT1093M组均未出现肿瘤再次生长;在体外杀伤实验中,注射病毒组的外周血CD45+细胞在靶效比为1∶ 40 时对CT26-luc杀伤效果明显,对4T1 细胞,各组杀伤效果较差.因此,重组溶瘤病毒VT1093M在结肠癌腹腔转移瘤模型中具有显著的抗肿瘤作用,且能激发小鼠产生较为持久的特异性免疫反应.
Abstract
To investigate the anti-tumor effects of oncolytic viruses that express a mouse anti-PD-1 antibody(VT1093M)on a celiac graft tumor model of colon cancer,the peritoneal graft model using CT26-luc cells is es-tablished in BALB/c mice.On day 8 after inoculation,mice are randomly divided into three groups(n = 5):nor-mal saline(NS)group,VT09X virus group and VT1093M virus group.A dose of 2.5×107pfu/250 μL is admin-istered once every other day for a total of five viral injections.On day 6 after the last injection,mice are sacrificed,ascites cells and CD45+ cells from peripheral blood are extracted for in vitro killing experiments.The rechallenge experiment is performed on day 13 after the initial disappearance of fluorescence in the injected virus group.Model-ing experiments determine that the optimal seeding condition is200 μL2.5×106 cells/mL cell suspension.The re-sults indicate the potential efficacy of VT1093M oncolytic viruses in treating colon cancer.In the drug efficacy ex-periment,both the VT09X and VT1093M groups exhibit significant tumor suppression compared with the NS group.The VT1093M group shows complete tumor disappearance during the treatment period with a more pronounced tumor-suppressive effect than the VT09X group,though no significant difference is observed between the two groups.In the rechallenge experiment,no tumor regrowth is observed in the VT1093M group.In the in vitro killing experiment,the peripheral blood CD45+ cells in the injected virus group exhibit obvious killing effect on CT26-luc when the target effect ratio is 1∶40,while the killing effect on 4T1 cells is poor.These findings demonstrate that the recombinant oncolytic virus VT1093M has a significant antitumor effect in the colon cancer abdominal metastasis model and it stimulates a relatively durable specific immune response in mice.
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