College of Veterinary Medicine, Northwest A&F University, Yangling 712100, P.R. China.
Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling 712100, P.R. China.
J Microbiol Biotechnol. 2022 Jan 28;32(1):6-14. doi: 10.4014/jmb.2107.07016.
spp. are facultative intracellular pathogens that invade, survive and proliferate in numerous phagocytic and non-phagocytic cell types, thereby leading to human and animal brucellosis. Outer membrane proteins (Omps) are major immunogenic and protective antigens that are implicated in virulence. A strain deleted of the gene has not been obtained which suggests that the Omp16 protein is vital for survival. Nevertheless, we previously constructed an conditional deletion strain of , ΔOmp16. Here, the virulence and immune response elicted by this strain were assessed in a mouse model of infection. Splenomegaly was significantly reduced at two weeks post-infection in ΔOmp16-infected mice compared to infection with the parental strain. The bacterial load in the spleen also was significantly decreased at this post-infection time point in ΔOmp16-infected mice. Histopathological changes in the spleen were observed via hematoxylineosin staining and microscopic examination which showed that infection with the ΔOmp16 strain alleviated spleen histopathological alterations compared to mice infected with the parental strain. Moreover, the levels of humoral and cellular immunity were similar in both ΔOmp16-infected mice and parental strain-infected mice. The results overall show that the virulence of ΔOmp16 is attenuated markedly, but that the immune responses mediated by the deletion and parental strains in mice are indistinguishable. The data provide important insights that illuminate the pathogenic strategies adopted by .
种属是兼性细胞内病原体，可入侵、存活和增殖于许多吞噬细胞和非吞噬细胞类型，从而导致人类和动物布鲁氏菌病。外膜蛋白（Omp）是主要的免疫原性和保护性抗原，与毒力有关。尚未获得缺失基因的菌株，这表明 Omp16 蛋白对于生存至关重要。然而，我们之前构建了一个条件缺失的，ΔOmp16。在这里，在感染小鼠模型中评估了该菌株引起的毒力和免疫反应。与亲本菌株感染相比，感染ΔOmp16 的小鼠在感染后两周脾肿大明显减少。在感染后时间点，感染ΔOmp16 的小鼠脾脏中的细菌负荷也明显降低。通过苏木精-伊红染色和显微镜检查观察到脾脏的组织病理学变化，结果表明与亲本菌株感染的小鼠相比，感染ΔOmp16 菌株减轻了脾脏组织病理学改变。此外，感染ΔOmp16 的小鼠和亲本菌株感染的小鼠的体液和细胞免疫水平相似。总体结果表明，ΔOmp16 的毒力明显减弱，但缺失和亲本菌株在小鼠中介导的免疫反应无法区分。这些数据提供了重要的见解，阐明了种属采用的致病策略。
