尿素酶疫苗在防治幽门螺杆菌感染的动物实验研究

目的利用人类幽门螺杆菌（Ｈｐ）感染的小鼠模型研究Ｈｐ粗抗原及纯化尿素酶在预防与治疗Ｈｐ感染的作用。方法超声粉碎制备Ｈｐ全菌抗原，化学提纯制备Ｈｐ尿素酶，霍乱毒素（ＣＴ）为免疫佐剂。实验分为预防与治疗两部分。预防部分把实验动物无特定致病菌（Ｓ．Ｐ．Ｆ．）ＢＡＬＢ／ｃ小白鼠分成５组，分别通过灌胃方法给予尿素酶（２５０μｇ）加ＣＴ（２μｇ）、Ｈｐ粗抗原（１ｍｇ）加ＣＴ（２μｇ）、生理盐水、单纯尿素酶（２５０μｇ）、单纯ＣＴ（２μｇ），每周１次，共４次。２周后再用活Ｈｐ灌胃，再４周后处死动物。治疗部分把已感染Ｈｐ的小白鼠分成５组，分组与治疗方法同预防部分，治疗结束后４周处死动物，取胃粘膜行尿素酶试验与改良Ｇｉｅｍｓａ染色检查Ｈｐ情况。结果预防实验的保护率分别为，尿素酶加ＣＴ７０％（７／１０），Ｈｐ粗抗原＋ＣＴ８０％（８／１０），生理盐水、单纯尿素酶、单纯ＣＴ保护率均为０。治疗实验各组Ｈｐ根除率分别为：尿素酶加ＣＴ６３．６％（７／１１），Ｈｐ粗抗原加ＣＴ４４．４％（４／９），生理盐水组、单纯尿素酶、单纯ＣＴ组均无治疗作用。结论由尿素酶加免疫佐剂组成的口服疫苗，不仅有预防Ｈｐ感染的作用，同时也有根除已感染的Ｈｐ的作用。

Immunization against Helicobacter pylori infection with urease vaccine:an animal model study

Objective To investigate the effects of the oral vaccine consisting of Helicobacter pylori (Hp) sonicated or purified urease in the prevention and treatment of Hp infection in a Hp infected mouse model. Methods The experiment was divided into two parts. In the first part, Specific Germ Free(S.P.F.)BALB/c mice were immunized by purified urease (250g) plus cholera toxin (CT) (2g), Hp sonicated (1mg) plus CT, saline, urease alone, CT alone orally respectively once a week for 4 weeks. Two weeks after the last immunization, all animals were challenged by alive Hp and sacrificed 4 times after the challenge. In the second part, Hp infected mice were treated with urease plus CT, Hp sonicated plus CT, saline, urease alone and CT alone orally once a week for 4 times. Four weeks after the last treatment, all animals were sacrificed and the stomach biopsies were collected to detected Hp by urease test and modified Giemsa Stain. Results =The prophylactic rates from Hp infection were 70% (7/10) in the group of urease plus CT and 80% in the group of Hp sonicated plus CT respectively. No protective effects were found in the groups of saline, urease alone or CT alone. Hp were eradicated in 63.3% (7/11) of mice treated with urease plus CT, 44.4% (4/9) or mice treated with Hp sonicate plus CT. No therapeutic effects were found in the groups of saline, urease alone or CT alone. Conclusion The oral vaccine consisting of urease and mucosal adjuvant CT is not only effective in preventing mice from Hp infection, but also effective in eradication of Hp infection.