目的　制备抗幽门螺杆菌 (Hp)尿素酶B亚单位 (UreB)减毒鼠伤寒杆菌活菌疫苗 ,观察其免疫效果。方法　构建表达UreB的原核表达载体PTc 0 1 UreB并转化减毒鼠伤寒杆菌SL32 6 1,得到重组菌SL32 6 1/PTc 0 1 UreB。应用抗Hp菌体蛋白兔血清行Western blot检测UreB在SL32 6 1中的表达。将SL32 6 1/PTc 0 1 UreB口服免疫Balb/c小鼠 ,12周后应用ELISA检测肠液和血清中的特异性抗体反应。SL32 6 1/PTc 0 1 UreB在Luria Bertani培养液中连续传代 6 0代以确定其稳定性。结果　成功构建PTc 0 1 UreB原核表达载体。Western blot显示 ,其转化减毒鼠伤寒杆菌SL32 6 1后能表达相对分子质量约 6 1× 10 3 的蛋白 ,与HpUreB亚单位相符 ,具有抗原性。口服免疫小鼠后 ,在肠液和血清中可分别检测到针对UreB的特异性IgA和IgG抗体。体外连续培养 6 0代未见PTc 0 1 UreB质粒丢失及对宿主细胞毒性。结论　表达HpUreB的减毒鼠伤寒杆菌SL32 6 1/PTc 0 1 UreB可用作抗Hp感染口服疫苗。 Objective To prepare live attenuated Salmonella typhimurium vaccine against UreB of Helicobacter pylori (Hp) and observe its immunogenicity. Methods The prokaryotic expression vector PTc 0 1 UreB expressing UreB was constructed and transformed into attenuated Salmonella typhimurium SL32 6 1, resulting in the recombinant strain SL32 6 1 / PTc 0 1 UreB. Western blot was used to detect the expression of UreB in SL32 6 1 using anti-Hp bacterial protein rabbit serum. Balb / c mice were orally immunized with SL32 6 1 / PTc 0 1 UreB and specific antibody responses in intestinal fluid and serum were measured by ELISA 12 weeks later. SL32 6 1 / PTc 0 1 UreB was continuously passaged in Luria Bertani broth for 60 generations to confirm its stability. Results The PTc 0 1 UreB prokaryotic expression vector was successfully constructed. Western blot showed that the recombinant protein could express about 6 1 × 10 3 protein after attenuated Salmonella typhimurium SL32 6 1, which was consistent with HpUreB subunit and was antigenic. After oral immunization of mice, specific IgA and IgG antibodies to UreB were separately detectable in intestinal juice and serum. In vitro continuous culture 60 generations without PTc 0 1 UreB plasmid loss and host cell toxicity. Conclusion The attenuated S. typhimurium SL32 6 1 / PTc 0 1 UreB expressing HpUreB can be used as an oral vaccine against Hp infection.