The common mucosal immune system was stimulated by oral immunisation with jack bean urease and the adjuvant cholera toxin. A high level of local antibody and serum antigbody was imduced in mice following hypermmunisation with thes combination No crass-reacting antibody was found against either Helicobaeter pylon or Helicobacter felis, No protection was observed against oral challenge of immunised mice with living H. felis disproving the interesting hypothesis of pallen and Clayton that plant urease might induce a protective immunity against helieobacter infection.

为构建表达HpaA蛋白的重组成减毒鼠伤寒沙门氏菌，并探讨以减毒鼠伤寒沙门氏菌为载体构建H pylori疫苗株的意义，应用PCR法从H pylori基因组DNA中扩增783bp的hpaA基因，经酶切-连接反应将其克隆入原核表达质粒pTre99A的NcoI-Sal I位点，并进行了核苷酸序列测定。重组质粒转化减毒鼠伤寒沙门氏菌SL3261，提取重组菌质粒，PCR和酶切鉴定，筛选阳性克隆。用SDS-PACE电泳和Western blot进行HpaA表达分析和鉴定，用薄层扫描分析HpaA含量。重组菌C57BL/6小鼠喂滋，分批两d和10d后处死小氧，取脾和未段回肠进行细菌培养，挑菌落提质粒鉴定。结果表明，经PCR和酶切证实，构建了含783bp hpsy基因的重组原核表达质粒，并将后者成功转化了减毒伤寒沙门氏菌。重组菌能表达约30kD HpaA蛋白，重组HpaA量约占全菌体蛋白量的38.9%，Western blot证实其有免疫反应性。小鼠重组菌喂灌两d或10d后，脾和未段回肠均发现携目的基因的菌落。这些结果提示了构建了表达H.Pylori HpaA R重组减毒鼠伤寒沙门氏菌,为制备以减毒伤寒沙门氏菌为抗原释放系统的H. pylori口康活疫苗进行了有益探索。

Helicobacter pylori is now accepted as the aetiological agent in peptic ulcer disease and has been characterised as a grade I carcinogen. The development of an effective vaccine is therefore desirable, although effective therapies for the eradication of the organism are available. The first step towards the developmetn of an anti-H. pylori vaccine was initiated by the demonstrion that a sonicate of H. felis can protect mice against infection with H. felis. Urease has been identified in the mouse model as a protective antigen. Other virulence factors, such as vacuolate cytotoxin and a heat shoek protein of H-Pylori, have been investigated as candidate vaccine components by the development of a new H. pylori mouse model. Vaccine adjuvants. delivery systems and therapeutic vaccination are likely to be the areas of major progress in the future.