MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.
Vet Microbiol. 2021 Dec;263:109274. doi: 10.1016/j.vetmic.2021.109274. Epub 2021 Nov 9.
Porcine proliferative enteropathy (PPE) is caused by the obligate intracellular bacterium Lawsonia intracellularis. Infection results in an enteric disease characterised by decreased growth performance of pigs, and presents a major economic burden for swine industries worldwide. Since vaccination is an effective technique for controlling PPE, novel effective vaccine platforms are need to be developed. In this study, five proteins of L. intracellularis were screened through animal experiments and the highly immunoprotective Omp2 protein was identified. Then, the immune efficacy of Omp2 was further evaluated based on humoral and cell mediated immune (CMI) responses, faecal bacterial shedding, histopathological lesions, immune barrier function of intestinal mucosa as well as digestive and absorptive capacity following challenge of mice with L. intracellularis. Mice immunised with Omp2 had reduced faecal shedding, fewer histopathological lesions and reduced bacteria colonisation of the ileum. Additionally, Omp2 immunised mice showed stronger serum IgG and IFN-γ levels, up-regulated Occludin and zonula occludens-1 (ZO-1) mRNA levels, as well as increased numbers of intestinal intraepithelial lymphocytes (IELs) and levels of sIgA. On the contrary, the activities of LPS, α-AMS and AKP were significantly increased. Our investigation indicated that immunization with Omp2 reduced the severity of clinical signs and provided efficacious immunoprotection for target animals against L. intracellularis infection in mouse model.
猪增生性肠炎（PPE）是由严格细胞内寄生的溶组织内劳森菌引起的。感染导致以猪生长性能下降为特征的肠道疾病，并给全球养猪业带来重大经济负担。由于疫苗接种是控制 PPE 的有效技术，因此需要开发新型有效的疫苗平台。在这项研究中，通过动物实验筛选了溶组织内劳森菌的 5 种蛋白，鉴定出高度免疫保护性的 Omp2 蛋白。然后，基于体液和细胞介导免疫（CMI）反应、粪便细菌脱落、组织病理学病变、肠道黏膜免疫屏障功能以及感染溶组织内劳森菌后小鼠的消化吸收能力，进一步评估了 Omp2 的免疫效果。用 Omp2 免疫的小鼠粪便脱落减少，组织病理学病变减少，回肠细菌定植减少。此外，Omp2 免疫的小鼠血清 IgG 和 IFN-γ水平更高，上调 Occludin 和 zonula occludens-1（ZO-1）mRNA 水平，上皮内淋巴细胞（IEL）数量和 sIgA 水平增加。相反，LPS、α-AMS 和 AKP 的活性显著增加。我们的研究表明，用 Omp2 免疫可减轻临床症状的严重程度，并为目标动物提供针对 L. intracellularis 感染的有效免疫保护，在小鼠模型中。
