Zhang Zhihui, Wu Haizhen, Xiao Jingfan, Wang Qiyao, Liu Qin, Zhang Yuanxing
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, PR China.
Vet Immunol Immunopathol. 2013 Aug 15;154(3-4):138-44. doi: 10.1016/j.vetimm.2013.05.012. Epub 2013 May 23.
Live attenuated vaccines are a promising application to control bacterial fish diseases. A live attenuated Vibrio anguillarum vaccine candidate was established in our laboratory to protect fish against vibriosis. To elucidate the mechanism of immunoprotection, it is necessary to compare the different immune responses to infection between vaccinated and non-vaccinated fish. In this study, the expression levels of pathogen-specific antibodies and immune-related genes upon challenge at 28 days post-vaccination were compared between vaccinated and non-vaccinated zebrafish. In the results, the specific antibody levels against virulent V. anguillarum in the vaccinated group did not rise significantly following infection, which suggested that high-affinity antibodies were induced by the vaccine. In the non-vaccinated group, the specific IgM response was triggered at 3 days post-infection and showed a delayed antibody response. Meanwhile, the transcription levels of the genes encoding the pro-inflammatory cytokine IL-1β and the chemokine IL-8 were more highly up-regulated in non-vaccinated fish than in vaccinated fish. This suggests that the overwhelming inflammatory response trigged by infection in non-vaccinated zebrafish was controlled in vaccinated zebrafish. Interestingly, the expression levels of adaptive immune-related genes were increased in vaccinated fish after challenge, compared to the non-vaccinated fish. These results suggest that inoculation with the live attenuated vaccine triggered protection by curbing inflammation and strengthening the adaptive immune response.
减毒活疫苗是控制细菌性鱼类疾病的一种有前景的应用。我们实验室构建了一种鳗弧菌减毒活疫苗候选株，用于保护鱼类抵抗弧菌病。为阐明免疫保护机制，有必要比较接种疫苗和未接种疫苗的鱼在感染时的不同免疫反应。在本研究中，比较了接种疫苗和未接种疫苗的斑马鱼在接种疫苗后28天受到攻击时病原体特异性抗体和免疫相关基因的表达水平。结果显示，接种疫苗组针对强毒鳗弧菌的特异性抗体水平在感染后未显著升高，这表明疫苗诱导产生了高亲和力抗体。在未接种疫苗组中，特异性IgM反应在感染后3天被触发，且抗体反应出现延迟。同时，编码促炎细胞因子IL-1β和趋化因子IL-8的基因转录水平在未接种疫苗的鱼中比在接种疫苗的鱼中上调得更高。这表明在接种疫苗的斑马鱼中，未接种疫苗的斑马鱼感染引发的压倒性炎症反应得到了控制。有趣的是，与未接种疫苗的鱼相比，接种疫苗的鱼在受到攻击后适应性免疫相关基因的表达水平有所增加。这些结果表明，接种减毒活疫苗通过抑制炎症和增强适应性免疫反应触发了保护作用。
