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目的观察表达鼠血管内皮生长因子受体2(VEGFR2,flk-1)的重组减毒鼠伤寒沙门疫苗菌对胶质瘤荷瘤小鼠的抗肿瘤血管及肿瘤生长抑制作用。方法构建真核表达载体pcDNA3 1.-flk-l,通过电转化法将pcDNA3 1.-flk-1导入减毒鼠伤寒沙门菌SL7207中,经由胃管饲于C57BL/6J小鼠,对胶质瘤荷瘤小鼠进行免疫预防及治疗。通过观察免疫动物的生存期,免疫荧光法检测肿瘤血管密度,评价重组疫苗菌的抗血管及肿瘤生长抑制作用。分离免疫小鼠的脾细胞,分析重组疫苗菌免疫后小鼠体内的特异性细胞毒性T细胞(CTL)应答。结果重组疫苗菌免疫能够明显减少肿瘤血管密度,延缓胶质瘤的生长,延长小鼠生存期,获得明显的抗肿瘤效果。重组疫苗菌免疫后可诱导小鼠脾淋巴细胞产生针对flk-l的CTL活性。结论表达鼠flk-l的重组减毒鼠伤寒沙门疫苗菌经口服免疫,可打破小鼠对于自身抗原flk-1的免疫耐受,诱导小鼠产生抗flk-1的特异性免疫反应,特异性杀伤肿瘤血管内皮细胞,预防和治疗小鼠胶质瘤。
Objective To observe the antitumor effects of recombinant attenuated Salmonella typhimurium Salmonella typhimurium vaccine expressing vascular endothelial growth factor receptor 2 (VEGFR2, flk-1) on glioma-bearing mice. Methods The eukaryotic expression vector pcDNA3 1.-flk-1 was constructed. The pcDNA3 1.-flk-1 was introduced into attenuated Salmonella typhimurium SL7207 by electrotransformation and was administered to C57BL / 6J mice via gastric tube. Tumor bearing mice for immunoprophylaxis and treatment. The survival time of immunized animals was observed. The tumor blood vessel density was detected by immunofluorescence and the anti-tumor and anti-tumor growth inhibition effects of the recombinant vaccine were evaluated. Splenocytes of immunized mice were isolated and the specific cytotoxic T cell (CTL) responses in mice after immunization with recombinant vaccines were analyzed. Results Recombinant vaccine immunization can significantly reduce tumor blood vessel density, delay the growth of glioma, prolong the survival of mice and obtain obvious anti-tumor effect. Recombinant vaccine bacteria can induce mouse splenic lymphocytes to produce CTL activity against flk-1. Conclusions Oral immunization of recombinant attenuated Salmonella typhimurium vaccine expressing murine flk-1 can break the mouse immune tolerance to flk-1 and induce specific immune response against flk-1 in mice Anti-tumor vascular endothelial cells, prevention and treatment of mouse glioma.