结核菌H37Ra在小鼠体内诱导的免疫应答

Immune Response Induced by Mycobacterium tuberculosis H37Ra in Mice

目的检测结核菌H37Ra免疫小鼠后产生的特异性细胞免疫和体液免疫应答水平。方法将BALB/c小鼠随机分为H37Ra组、BCG组和生理盐水(NS)组,分别进行免疫,免疫8周后处死小鼠,分离血清,ELISA间接法测定血清特异性抗PPDIgG抗体的水平,流式细胞分析仪检测脾脏T淋巴细胞亚群的变化。脾淋巴细胞经体外培养、PPD刺激后,MTT法检测脾淋巴细胞的刺激指数,ELISA法检测培养上清液中IFN-γ和IL-4的水平。结果H37Ra免疫小鼠血清中抗PPDIgG抗体、脾脏CD3+T细胞和CD4+T细胞的百分率、脾淋巴细胞刺激指数、IFN-γ和IL-4水平均显著高于NS对照组,但与BCG组差异无显著意义。各组间脾脏CD8+T细胞、CD4+T/CD8+T比值差异均无显著意义。结论H37Ra免疫小鼠后,可以产生特异性的细胞免疫和体液免疫应答,有望成为结核疫苗的候选抗原。

Objective To determine the specific cellular and humoral immune response levels induced by Mycobacterium tuberculosis H37Ra in mice. Methods Divide BALB/c mice into three groups and immunize by H37Ra, BCG and normal saline （NS） respectively. Kill the mice 8 weeks after immunization and determine the specific IgG level against PPD in sera by ELISA, and the T lymphocyte subgroup in spleens by flow cytometry. Culture splenic lymphocytes in vitro, stimulate with PPD and determine the stimulating index by MTr method, and the IFN-γ and IL-4 levels in culture supematant by ELISA. Results The specific IgG level against PPD in sera, the percentages of CD3 ^＋ and CD4 ^＋ T lymphocytes in spleen, the stimulating index of splenic lymphocytes as well as IFN-γ and IL-4 levels of mice immunized by H37Ra was significantly higher than those by NS, while showed no significant difference with those by BCG. However,no significant difference was observed in the percentage of CD8 ^＋ T lymphocytes or the ratio of CD4 ^＋ T lymphocytes to CD8 ^＋ T lymphocytes of various groups. Conclusion H37Ra induced specific cellular and humoral immune responses in mice and might be used as a candidate antigen for development of tuberculosis vaccine.