牛支原体感染促进牛病毒性腹泻病毒感染机制的研究

犊牛肺炎多由细菌与病毒混合感染引起，造成奶牛养殖业巨大经济损失，而相关研究极少。本团队在前期研究中发现，用灭活牛支原体疫苗免疫试验犊牛，可以显著降低犊牛肺炎发病率。基于此，我们针对和BVDV在犊牛肺炎发病过程中的可能协同作用提出两个假说：1）M. bovis感染易感染细胞后，有利于BVDV黏附，入侵细胞和胞内复制。2）M. bovis感染易感动物后，有利于BVDV入侵机体，分布和定植；促进感染部位组织因子分泌，加剧病理损伤。本研究拟用定量PCR监测BVDV在组织内的分布和定量，过氧化物酶单层细胞实验和ELISA监测M. bovis和BVDV抗体水平，组织病理学评分方法评定M. bovis促进BVDV感染造成病理损伤等方法，探索M. bovis与BVDV在体内、外协同感染的主要途径。本研究为揭示混合感染中细菌和病毒协同作用机制奠定基础，为治疗牛支原体肺炎提供新思路。

Calf pneumonia is mainly caused by the mixed infection of bacteria and virus, which causes huge economic loss in the dairy industry, but the related research is very few. Our team found that the incidence rate of calf pneumonia was significantly reduced by using the Mycoplasma vaccine vaccine. Based on this, we put forward two hypotheses about the possible synergistic effect of M. bovis and BVDV in the process of calf pneumonia: 1) M. bovis is beneficial to BVDV adhesion, invasion and intracellular replication after infecting susceptible cells. 2) After M. bovis infects susceptible animals, it is beneficial for BVDV to invade, distribute and colonize the body, promote the secretion of tissue factors at the infected site and aggravate the pathological damage. In this study, quantitative PCR was used to monitor the distribution and quantification of BVDV in tissues, peroxidase monolayer cell experiment and ELISA were used to monitor the antibody levels of M. bovis and BVDV, histopathological evaluation method was used to evaluate the promotion of M. bovis to BVDV infection and the pathological damage, and the main ways of M. bovis and BVDV co infection in vivo and in vitro were explored. This study laid a foundation for revealing the synergistic mechanism of bacteria and virus in mixed infection, and provided a new idea for the treatment of Mycoplasma bovis pneumonia.