以沙门氏菌为载体的DNA疫苗对小鼠肿瘤的预防作用

DNA vaccine based on live attenuated Salmonella leads to tumor regression and prolongation of survival in mice.

目的:探讨减毒鼠伤寒沙门氏菌为载体的DNA口服疫苗防治小鼠肿瘤的可行性。方法:通过电转化法将真核表达载体pCMVmIL-12、EGFPN1导入减毒鼠伤寒沙门氏菌SL3261中,经由胃管饲于BALB/c和C57BL/6小鼠。6周后分别用4T1乳腺癌细胞和Lewis肺癌细胞进行攻击。通过流式细胞仪、共聚焦显微镜检测绿色荧光蛋白在小鼠各组织中的表达,通过PCR和ELISA的方法检测mIL-12基因的整合和表达情况。并考察肿瘤的受抑情况和小鼠的生存期。结果:在小鼠的肝、脾、小肠、肾脏和肿瘤中可检测到绿色荧光蛋白的表达和相应细胞因子基因的整合。血清中相应的细胞因子水平较对照组明显升高(P<0.05),生存期远远超过对照组小鼠(P<0.05)。结论:减毒沙门氏菌可作为口服基因治疗载体,为肿瘤的预防和治疗提供一条简便、安全、有效的途径。

Objective： To study the possibility of oral eytokine gene therapy using live attenuated Salmonella as a vector against nior. Methods： A live attenuated AraA- autotrophie mutant of Salmonella typhimurlum （SL3261） was used as carrier for eukaryotie expression vectors EGFPN1 pCMVmIL-12,whieh was administered orally to BALB/e and C57BL/6 mice. After 6 weeks,these mice were challenged with 4T1 or Lewis tumor eells respectively. Flow eytometer and eonfoeal were used to detect the expression of GFP in mice tissues. PCR and ELISA were used to detect the integration and expression of raiL-12 gene. The survival time of mice was also investigated.Results：GFP expression and mIL-12 gene integration could be detected in miee＇s liver,spleen,intestinal,kidney and tumor. The serum levels of mIFN-γ and raiL-12 increased significantly in the mIL-12 orally treated mice （P〈0.05）; which resulted in the prOlongation of the survival time of those mice compared with the control group （P〈0.05）. Conclusion： Oral gene therapy using live attenuated Salmonella has the potential to be a simple, effective and above all, safe way against tumor.