Guangxi Key Laboratory for Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Institute of Fisheries, Nanning, 530021, China.
Guangxi Key Laboratory for Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Institute of Fisheries, Nanning, 530021, China.
Fish Shellfish Immunol. 2019 Apr;87:714-720. doi: 10.1016/j.fsi.2019.02.003. Epub 2019 Feb 7.
In this study, the tilapia was orally vaccinated by the attenuated Streptococcus agalactiae(S. agalactiae) strain YM001, and the distribution and the pathological effect of strain YM001 in different intestinal segments of tilapia were evaluated by real-time PCR(qPCR), immunohistochemistry(IHC) and histomorphology. The qPCR results showed that the number of bacteria was the highest in the intestinal tracts at 12 h post oral gavage in the YM001 group, then began to decrease sharply and eliminated at 7 d. And the number of bacteria was highest in the foregut, hindgut, and rectum at 12 h, 24 h, and 3 d, respectively. IHC indicated that bacteria mainly distributed in the margin epithelium and the goblet cells at 12 h - 24 h, and in the submucosa and muscle layer in the YM001 group in 3 d post gavage, then almost disappeared at 7 d. Histological examination of intestines post gavage displayed that an inflammation was observed at 7 d in the YM001 group and the intestinal structure was fully recovered at 15 d. and the intestinal structure was fully recovered at 15 d. Conclusion: The attenuated S. agalactiae vaccine strain YM001 could enter the intestinal tissue after oral gavage and had a strong spatial and temporal selectivity in the intestinal tract, which could cause obvious mucosal immune response and mild pathological reaction, but the pathological change could be gradually repaired with the extinction of bacteria in the body.
在这项研究中，牙鲆经口接种减毒马链球菌(Streptococcus agalactiae)YM001 菌株，通过实时 PCR(qPCR)、免疫组织化学(IHC)和组织形态学评估了 YM001 菌株在牙鲆不同肠道段的分布和病理效应。qPCR 结果显示，YM001 组在口服灌胃后 12 h 肠道细菌数量最高，然后开始急剧下降，并在 7 d 时被清除。细菌数量在 12 h、24 h 和 3 d 时分别在前肠、后肠和直肠中最高。IHC 表明，细菌主要分布在 12 h-24 h 的边缘上皮和杯状细胞中，在灌胃后 3 d 的 YM001 组中分布在黏膜下层和肌肉层，然后在 7 d 时几乎消失。肠道灌胃后的组织学检查显示，YM001 组在 7 d 时出现炎症，15 d 时肠道结构完全恢复。结论：减毒马链球菌疫苗株 YM001 经口服灌胃后可进入肠道组织，在肠道内具有很强的时空选择性，可引起明显的黏膜免疫反应和轻微的病理反应，但随着体内细菌的消失，病理变化可逐渐得到修复。
