口服幽门螺杆菌疫苗候选株对小鼠肠道菌群的影响

Effects of Oral Helicobacter pylori Vaccine Candidates on Intestinal Flora in Mice

目的:考察口服幽门螺杆菌疫苗候选株SH02对小鼠肠道菌群的影响。方法:采用PCR扩增的方法检测疫苗用载体菌侵袭性相关基因缺失状况,用豚鼠角结膜侵袭试验进一步确证其是否具有上皮细胞侵袭能力;用小鼠口服灌胃的方式检测SH02在小鼠体内的组织分布,在肠道的存留时间与活菌数;取小鼠灌胃前(0 d)和灌胃后(2、8 d)的粪便样本,提取基因组DNA,用细菌16S r RNA基因高通量测序的方式,分析评价口服幽门螺杆菌疫苗候选株SH02对小鼠肠道正常菌群的影响。结果:载体菌FWL01侵袭性相关基因缺失,不具有对上皮细胞的侵袭能力;SH02经口服灌胃小鼠后不能侵入机体组织内部,仅在小鼠肠道可以检测到疫苗株活菌,灌胃后24、48 h肠道粪便中活菌数分别为1.19×10~5和2.42×10~3CFU/g,72和96 h在小鼠肠道粪便中没有检测到SH02活菌存在;细菌16S r RNA基因高通量测序与分析结果表明,口服幽门螺杆菌疫苗候选株SH02对小鼠肠道菌群不会产生明显的影响。结论:口服幽门螺杆菌疫苗候选株SH02对小鼠肠道正常菌群没有明显影响。

Objective: To investigate the effect of oral administration of Helicobacter pylori vaccine strain SH02 on intestinal flora in mice. Methods: PCR-amplified method was used to detect the deletion of invasiveness-related genes of vaccine carrier strain. The invasion test of cornea and conjunctiva in guinea pigs was used to further confirm whether it has the ability of epithelial cell invasiveness. After oral gavage to mice, SH02 was tested the tissue distribution, the survival time in the intestine and viable count in stool samples. The stool samples of mice before gavage(0 day) and after gavage(2, 8 days) were collected, and their genomic DNA was extracted. The high-throughput sequencing of bacterial 16 S r RNA gene to analyze and evaluate the effects of oral administration of H.pylori vaccine strain SH02 on normal intestinal flora of mice. Results: The vaccine carrier strain FWL01 has lost the invasive related genes and the ability to invade the epithelial cells. After oral gavage, SH02 can not invade the body tissue of mice and be detected only in the intestinal tract. The number of living bacteria in intestinal feces was 1.19×10~5 CFU/g 24 h after oral gavage, 2.42×10~3 CFU/g after 48 h. SH02 was not detected at 72 h and 96 h. The high-throughput sequencing of bacterial 16 S r RNA gene showed that oral administration of H.pylori vaccine strain SH02 had no significant effect on mouse intestinal flora. Conclusion: Oral administration of Helicobacter pylori vaccine strain SH02 has no significant effect on normal intestinal flora in mice.