Ipr1重组卡介苗对小鼠结核病的治疗效果

Therapeutic effects of murine Ipr1 recombinant BCG vaccine on Mycobacterium tuberculosis infection in murine model

目的评估携带小鼠胞内病原体抗性基因1(intracellular pathogen resistance1,Ipr1)质粒(pBOGI)的重组卡介苗(BCG)对结核分枝杆菌(Mtb)感染的治疗效果。方法BALB/c小鼠30只,随机分为3组:分别滴鼻给予磷酸盐缓冲液(PBS)、BCG和重组BCG,2周后用人型Mtb H37Rv标准株感染所有小鼠;感染后分别用PBS、BCG和重组BCG治疗7次;末次治疗后处死小鼠,检测肺脾荷菌量,肺脾脏器指数,血清IFN-γ、IL-10及TNF-α分泌水平和肺脾组织中Ipr1的表达,同时观察小鼠肺脾组织病理改变情况。结果重组BCG组肺脾荷菌量比PBS组和BCG组显著降低(P<0.01);重组BCG组肺脾脏器指数比PBS组和BCG组显著降低(P<0.05);重组BCG组血清IFN-γ分泌水平比PBS组和BCG组显著升高(P<0.01)。用免疫组化检测到小鼠肺脾组织中有Ipr1表达。PBS组肺组织病理改变以渗出为主,病变广泛;重组BCG组肺部病变最轻,肺泡结构基本正常;BCG组病变范围局限,病变程度界于PBS组与重组BCG组之间;各组间比较脾脏病理改变不明显。结论携带小鼠Ipr1基因的重组BCG对结核分枝杆菌感染有一定的治疗作用。

Objective To evaluate the effects of recombinant BCG vaccine encoding murine Ipr1 on Mycobacterium tuberculosis infection in rats.Methods Thirty BALB/c mice were randomized into 3 groups which were intranasally given PBS,BCG and recombinant BCG respectively.Two weeks later,the 3 groups were infected with Mycobacterium tuberculosis and were intranasally treated with PBS,BCG,recombinant BCG for once per 3 d,7 times totally respectively.The mice were sacrificed after the final treatment.The viable quantity of bacteria in the lungs and the spleens was detected. The weight indexes of the lungs and the spleens were calculated. ELISA was used to detect the levels of IL-10, TNF-α and IFN-γ in the serum. The expression of Iprl in lung and spleen tissues was detected by immunohistochemistry. Lungs and spleens were prepared for pathological analysis. Results In the recombinant BCG group, significant reduce was observed in number of colony forming units and weight indexes of lungs and spleens compared with the PBS group and the BCG group in the same murine strain. The level of IFN-γ was significantly increased in the recombinant BCG group compared with the other 2 groups. The expression of Iprl in the tissues was found in the recombinant BCG group. The pathological changes in lungs of the recombinant BCG group and the BCG group were localized, while those in the PBS group were extensive. There was no significant changes in the spleen of all groups. Conclusion The recombinant BCG encoding murine Iprl has therapeutic effects on murine Mycobacterium tuberculosis infection.