四种卡介苗重组疫苗对结核病的预防作用

The prophylactic effects of four recombinant BCG vaccines for tuberculosis in mice

目的:评价esat6-卡介苗重组疫苗、mpt64-卡介苗重组疫苗、ag85a-卡介苗重组疫苗、ag85b-卡介苗重组疫苗对结核病预防效果。方法:观察四种卡介苗重组疫苗对结核分枝杆菌感染的预防试验中实验动物半数死亡时间、一定时间内的死亡率、T细胞及B细胞免疫功能等指标。结果:卡介苗重组疫苗及卡介苗与生理盐水对照组比都能延长结核分枝杆菌感染小鼠的半数死亡时间,降低2个月内的死亡率。其中esat6-卡介苗重组疫苗组效果最显著,与卡介苗组比差异有统计学意义。实验结束时,esat6-卡介苗重组疫苗组小鼠脏器大体病变较其他各组轻。脏器结核分枝杆菌培养结果表明:esat6-卡介苗重组疫苗组小鼠脏器内结核分枝杆菌较少,其他各组间无显著区别。抗体检测结果表明,ag85a-卡介苗重组疫苗免疫小鼠抗体水平显著升高,其他各组之间无差别。淋巴细胞增殖实验结果,各组之间差异无统计学意义。结论:初步实验结果表明esat6-卡介苗重组疫苗对结核菌的预防作用强于卡介苗。

Objective To evaluate the prophylactic effects of four recombinant BCG vaccines secreting the esat6, mpt64, ag85a, and ag85b proteins of Mycobacterium tuberculosis for tuberculosis, respectively. Methods Sisty BALB/c mice were divided into 6 groups randomly,and were immunized with esat6-secreting recombinant BCG, mpt64-secreting recombinant BCG, ag85a-secreting recombinant BCG,ag85b-secreting recombinant BCG, BCG, and saline, respectively. The mice were then challenged with 0.4 mg M. tuberculosis H37Rv in 30 days after immunization. The 50% individual lethal date, mortality in 2 months, and the immune function of T and B cells were observed. Results As compared with negative control, BCG or recombinant BCG vaccines could prolong the 50% individual lethal date and decrease the mortality in 2 month after M. tuberculosis attacked. Mpt64- secreting recombinant BCG,ag85a-secreting recombinant BCG,ag85b-secreting recombinant BCG showed no significant improvements upon conventional BCG vaccine in prophylactic effect against M.tuberculosis.But as compared with parental BCG, immunization with esat6-secreting recombinant BCG resulted in a remarkable reduction in bacterial burden, numbers of tubercles, pathology in the organs, and enhanced survival time. Conclusion The protective effects of esat6-seereting recombinant BCG were significantly higher than that of the parental BCG.