Characteristics of Brucella abortus vaccine strain A19 reveals its potential mechanism of attenuated virulence
Characteristics of Brucella abortus vaccine strain A19 reveals its potential mechanism of attenuated virulence
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DOI：
10.1016/j.vetmic.2021.109007
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发表时间：
2021-02-11
影响因子：
3.3
通讯作者：
Yu, Shengqing
中科院分区：
文献类型：
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作者：
Cheng, Zhimin;Li, Zichen;Yu, Shengqing
布氏杆菌疫苗接种是控制家畜布氏杆菌病最重要的策略之一。A19株是我国目前控制布鲁氏菌病的有效疫苗。然而，A19菌株的生理和减毒特性尚未详细研究。在这项研究中，我们比较了A19与野生型菌株S2308的表型特征。毒力试验表明，A19在小鼠慢性感染阶段毒力明显减弱。在生长分析中，A19在指数生长期表现出快速生长，在稳定期表现出早熟。采用TaqMan qPCR检测A19感染的巨噬细胞的炎症反应，表明A19感染的巨噬细胞的炎症水平高于S2308感染的巨噬细胞的炎症水平。细胞死亡分析表明，A19对巨噬细胞没有细胞毒性。感染细胞后，A19的侵入、存活和运输能力均降低，细胞内A19几乎不排斥溶酶体相关标志物LAMP-1，提示A19在宿主细胞内无法逃脱溶酶体降解。进一步的敏感性试验表明，A19菌株对应激和杀菌因子的敏感性高于S2308菌株，Western blot和银染分析表明，A19菌株具有与S2308菌株不同的外膜蛋白表达模式，并降低了LPS O抗原的表达。这些数据使我们对A19疫苗株有了更详细的了解，这将有助于改进现有的布鲁氏菌疫苗，克服其缺陷。
Brucella vaccination is one of the most important strategies for controlling brucellosis in livestock. The A19 strain was the effective vaccine used to control brucellosis in China. However, the characteristics of physiological and attenuated virulence of the A19 strain are not investigated in detail. In this study, we compared the phenotypic characteristics of the A19 to the wild-type strain S2308. Virulence test showed that the A19 was significantly attenuated at chronic infection stage in infected mouse model. In growth analysis, the A19 exhibited a quick growth at exponential phase and premature at stationary phase. The inflammatory response of macrophages infected by the A19 was detected using TaqMan qPCR assay, indicating that the inflammatory level of the A19-infected macrophages was higher than that of the S2308 infection. Cell death analysis showed that the A19 was not cytotoxic for macrophages. Cell infection showed that the A19 reduced its ability to invade, survive and traffic within host cells, and the intracellular A19 hardly excludes lysosome-associated marker LAMP-1, suggesting that the A19 can't escape the lysosome degradation within host cells. In further study, the sensitivity test exhibited that the A19 is more sensitive to stress and bactericidal factors than the S2308 strain, Western blot and silver staining analysis exhibited that the A19 has a different expression pattern of OMPs and reduces LPS O antigen expression relative to the S2308 strain. Those data give us a more detailed understanding about the A19 vaccine strain, which will be beneficial for improvement of current Brucella vaccine and overcoming its defects.