结核分枝杆菌Ag85B基因疫苗免疫保护作用的初步研究

目的:研究编码结核分枝杆菌分泌蛋白Ag85B的基因疫苗pTB30m和pTB30s对免疫动物的保护作用。方法:以基因疫苗pTB30m和pTB30s肌注免疫BALB/c小鼠。免疫完成6 wk后,用5×105 CFU的MTB H37Rv毒株经小鼠尾静脉攻击感染。同时用尼龙毛柱分离基因免疫BALB/c小鼠的T细胞,并以5×106 T细胞/只小鼠过继免疫正常BALB/c小鼠,立即用105 CFU的MTB毒株经小鼠尾静脉攻击感染。4 wk后分别计数脾脏中的细菌负荷。结果:与生理盐水对照组相比较,pTB30m及pTB30s质粒免疫组BALB/c小鼠脾脏中的细菌负荷均减少,分别为0.645(log10 CFU,P<0.01)和0.839(log10CFU,P<0.001);而空质粒对照组小鼠脾脏中的细菌负荷减少较少。经质粒pTB30m和pTB30s免疫的BALB/c小鼠的T细胞,过继免疫的正常BALB/c小鼠,对攻击感染的MTB H37Rv毒株在脾脏中的增殖具有部分抑制作用。结论:pTB30s免疫的BALB/c小鼠,对MTB H37 Rv毒株攻击的保护作用优于pTB30m质粒免疫,有望进一步用于结核病的防治研究。

Protective efficacy of DNA vaccines encoding mycobacterium tuberculosis Ag85B protein

AIM: To explore protective efficacy of pTB30m and pTB30s encoding Ag85B protein against infection with M. tuberculosis H37RV. METHODS: BALB/c mice were infected intravenously with 5 x 105 CPU of M. tuberculosis H37RV six weeks after the last vaccination of pTBSOm and pTBSOs. At the same time, normal BALB/c mice were injected intravenously with 5 x 106 T cells separated from immunized BALB/c mouse spleen through nylon wool column, and challenges were injected with 105 CFU of M. tuberculosis immediately intravenously. After 4 weeks, the CPU in spleens of infected mice were counted respectively. RESULTS: Vaccination with pTB30m and pTB30s produced significant protection a-gainst M. tuberculosis proliferation in the mouse spleens following challenge. As compared with the saline-injected mice, CPU in spleens of the mice vaccinated with pTB30m or pTB30s were reduced significantly, being 0.645(log10CFU, P <0.01) and 0. 839(log10CFU, P< 0.001), respectively. In contrast, bacterial load in the mice spleens vaccinated with empty plasmid only had little reduction. After adoptive immunization by T cells from the mice vaccinated with pTB30m and pTB30s , the mice might induce partial protection a-gainst M. tuberculosis proliferation in the mouse spleens following challenge. CONCLUSION; Protective efficacy of the mice immunized with pTB30s against challenge with M. tuberculosis virulent strain was better than that immunized with pTB30m. Thus, pTB30s is a promising DMA vaccine with respect to the prevention and treatment of tuberculosis.