幽门螺杆菌CagA抗原性多态性分析

目的 了解我国幽门螺杆菌CagA抗原性的多态性，为临床血清学诊断CagA阳性菌株感染提供实验依据，以及是否存在特定胃十二指肠疾病相关的CagA抗原性型提供线索。方法 采用Western blots方法，比较38株我国幽门螺杆菌分离株的CagA与3种不同胃肠疾病分离株兔免疫血清的反应强度。分析不同抗原性类型CagA与疾病的关系。结果 任何一种血清均不能识别所有CagSA，但任一CagA至少可被一种血清识别，多数菌株CagA的抗原性与CAPM N62接近；抗原性与NCTC11637接近的CagA可能与消化性溃疡相关，但不显著。结论 我国不同幽门螺杆菌菌株CagA抗原性存在明显多态性，血清学方法诊断CagA阳性菌株感染时应至少使用3种抗原或抗体，不同抗原性类型CagA与胃十二指肠疾病的关系有待进一步研究。

Analysis of antigenic heterogeneity of CagA of Helicobacter pylori strains

Objective To examine the antigenic heterogeneity of CagA of Helicobacter. pylori for identification of CagA positive Hp infection serologically, and determine the existence of gastroduodenal diseases specific CagA antigenic subsets. Methods The antigenic heterogeneity of CagA of different Hp strains was determined by comparing their reactivity to three different types of rabbit sera immunized with CAPM N62, NCTC11637, CAPM Z-2 respectively by Western blots, its' association with different gastroduodenal diseases was analyzed. Results None of the three immune sera could recognize CagA of all isolates, whereas each CagA could be recognized by at least one type of immune serum. The antigenity of CagA of most Chinese Hp strains was similar to that of CAPM N62, those reacted most strongly with serum immunized by NCTC11637 was more likely but not significantly correlated to peptic ulcer. Conclusion CagA of different Chinese Hp strains are in high antigenic heterogeneity, at least three types of CagA antigen or its antibody should be used for determining CagA positive Hp strain infection by serological method. The relationship between different antigenic subsets of CagA and gastroduodenal diseases need further investigation.