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目的 对幽门螺杆菌 (Hp)ureB核苷酸序列及推定氨基酸序列进行同源性比较分析 ,确定Hp菌株的ureB基因差异性 ,为疫苗的研究和诊断用品的评价提供依据。方法 自行设计引物 ,PCR扩增来自国内不同病人的 4株Hp菌株的ureB基因 ,与pGEM T载体克隆连接、测序 ;进一步同GenBank上发表的其他 4株国外Hp菌株ureB的全基因序列进行比较分析。结果 8株Hp菌株的ureB基因序列出现了 3种长度 ,CAPMF3和CPM6 30分别为 12 6 9bp和 16 80bp ,其他为 1710bp。 6株1710bp的ureB基因序列的分析表明 ,国外 3株Hp的ureB同源性较高 ,三者氨基酸的同源性达到10 0 %。而国内 3株Hp的ureB变异较大 ,推定氨基酸同源性为 98 7%～ 98 9%。结论 UreB作为保护性抗原时存在免疫保护覆盖率问题 ,研究疫苗和诊断用品时要注意选择使用在人群中流行占优势的Hp菌株的高度保守的UreB抗原肽 ,使其具有更高的覆盖率。
Objective To compare the homology of nucleotide and deduced amino acid sequence of Hp ureB to determine the difference of ureB gene between Hp strains and provide basis for the research of vaccine and evaluation of diagnostic products. Methods Primers were designed to amplify the ureB gene of four Hp strains from different domestic patients by PCR and cloned into pGEM T vector and sequenced. The sequence of ureB gene was further compared with that of the other 4 foreign strains of urease Hp strain published in GenBank . Results There were three kinds of ureB gene sequences in 8 strains of Hp strains, including 12 6 9 bp and 16 80 bp for CAPMF3 and CPM6 30, and 1710 bp for others. The analysis of ureB gene sequences of 6 1710bp showed that the homology of the ureB of the three foreign Hp strains was high, and the homology of the three amino acids was 100%. However, the ureB variation of the three Hp strains in China is large, and the deduced amino acid homology is 98.7% ~ 98.9%. Conclusions There is a problem of immunoprotection coverage when using UreB as a protective antigen. In the study of vaccines and diagnostic products, we should pay attention to choosing a highly conserved UreB antigen peptide of the predominant Hp strain in the population to have higher coverage.