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目的 研究以减毒鼠伤寒沙门菌为载体构建的重组幽门螺杆菌 (Hp)疫苗诱导小鼠产生保护性免疫应答的机制。方法 将表达Hp尿素酶B亚单位 (UreB)、黏附素 (HpaA)及尿素酶B亚单位/黏附素融合蛋白 (UreB/HpaA)的减毒鼠伤寒沙门菌 (Salmonellatyphimurium)给小鼠分别灌胃 ,另设单纯减毒鼠伤寒沙门菌和生理盐水免疫鼠为对照。免疫 4周后以Hp活菌攻击 ,观察各组小鼠的免疫保护率 ,攻击前后血清中抗Hp抗体IgG1、IgG2a和IgA的变化 ,小鼠脾脏和胃黏膜中γ干扰素 (IFN γ)和白介素 4 (IL 4 )mRNA表达变化。结果 UreB、HpaA及UreB/HpaA组的免疫保护率分别为 5 0 % ,4 1%和 77%。和生理盐水组相比 ,攻击前各鼠伤寒沙门菌免疫组IgG1、IgG2a均轻度升高而IgA无变化 ,攻击后各鼠伤寒沙门菌免疫组IgG2a升高显著并以UreB/HpaA组为最 ,而IgG1和IgA的升高无统计学差异。胃黏膜攻击前生理盐水组无IFN γ表达 ,其余各组均 10 0 %表达 ;攻击后生理盐水组IFN γ轻度表达 ,但仍明显低于各鼠伤寒沙门菌免疫组。IL 4在攻击前后各组均无表达。脾IFN γ和IL 4在所有组攻击前后均全部表达。结论 以减毒鼠伤寒沙门菌为载体构建的Hp疫苗在小鼠体内诱导出以TH1反应为主的保护性免疫应答
Objective To study the mechanism of recombinant Helicobacter pylori (Hp) vaccine induced by protective attenuated Salmonella typhimurium in mice. Methods Mice were inoculated intraperitoneally with Salmonella typhimurium expressing Hp urease B subunit (UreB), adhesin (HpaA) and urease B subunit / UreB / HpaA , Another set of pure attenuated Salmonella typhimurium and saline immunized mice as a control. After 4 weeks of immunization, the mice were challenged with Hp viable cells to observe the immune protection rate, the changes of anti-Hp antibodies IgG1, IgG2a and IgA in serum before and after challenge, the levels of IFN-γ in the spleen and gastric mucosa Changes in interleukin 4 (IL 4) mRNA expression. Results The immune protection rates of UreB, HpaA and UreB / HpaA groups were 50%, 41% and 77% respectively. Compared with the saline group, the IgG1 and IgG2a of the groups immunized with Salmonella typhimurium before the challenge were slightly elevated but the IgA did not change. The IgG2a levels of the Salmonella typhimurium groups were significantly increased after the challenge and were highest in the UreB / HpaA group , While there was no significant difference in the increase of IgG1 and IgA. The IFN-γ expression in normal saline group before gastric mucosal attack was 100%. The expression of IFN-γ in normal saline group was mild but still significantly lower than that of Salmonella typhimurium group after challenge. IL 4 was not expressed in all groups before and after challenge. Splenic IFN [gamma] and IL4 were all expressed before and after challenge in all groups. Conclusion The Hp vaccine constructed with attenuated Salmonella typhimurium as a carrier induces a protective immune response predominated by TH1 in mice