Biotechnology and Biopharmaceuticals Laboratory, Pathophysiology Department, School of Biological Sciences, Universidad de Concepción, Victor Lamas 1290, P.O. Box 160C, Concepción, Chile.
Biotechnology and Biopharmaceuticals Laboratory, Pathophysiology Department, School of Biological Sciences, Universidad de Concepción, Victor Lamas 1290, P.O. Box 160C, Concepción, Chile.
Vaccine. 2019 Feb 28;37(10):1340-1349. doi: 10.1016/j.vaccine.2019.01.029. Epub 2019 Jan 30.
Proliferative enteropathy, caused by Lawsonia intracellularis, represents a threat for swine industry. Current vaccines are effective but difficult to obtain and scaled up, because of demanding bacterial culture conditions. In this work, a subunit vaccine candidate against L. intracellularis was developed and its efficacy was evaluated in vivo, alone or co-formulated with pig recombinant IFN-α. The vaccine formulation contains three chimeric antigens: two outer membrane proteins and a secreted one, which were engineered by adding T epitopes using bioinformatics tools. After simultaneously expressing the three antigens in E. coli, its immunogenicity was tested in mice and pigs. Antigens co-formulated with porcine IFN-α were also assayed in the last species. Immune response was assessed by ELISA and qPCR, and histopathological studies of intestinal epithelial tissue were performed after challenge. Mice and pigs showed an increased IgG response against chimeric antigens. Particularly, there were significant differences in the antibody response when porcine IFN-α was co-administrated with L. intracellularis antigens. Besides, mRNAs from il12 and cd4 marker were detected during the first week after immunization of pigs, suggesting a Th1-type cellular immune response. The significant enhancement of oas2 gene expression indicates the effect exerted by porcine IFN-α. Post-mortem histopathological analysis post-challenge revealed damage only into epithelial cells of the gastrointestinal tract from animals of the negative control group. Injuries were related to atrophy of the intestinal villi, where a decrease of globet cells and a greater migration of lymphocytes were observed. Overall, our results demonstrated that the vaccine candidate elicited significant humoral and cellular immune responses. Besides, histopathological analysis suggested that vaccinated animals were protected against experimental L. intracellularis infection. This research constitutes a step forward to the generation of the first recombinant chimeric vaccine against L. intracellularis, representing a faster, easier and cost effective approach to counteract the porcine proliferative enteropathy.
细胞内劳森菌引起的增殖性肠炎对养猪业构成威胁。目前的疫苗虽然有效，但由于对细菌培养条件的要求较高，因此难以获得和扩大规模。在这项工作中，开发了一种针对细胞内劳森菌的亚单位疫苗候选物，并在体内评估了其单独或与猪重组 IFN-α 联合使用的功效。该疫苗配方包含三种嵌合抗原：两种外膜蛋白和一种分泌蛋白，这些蛋白是通过使用生物信息学工具添加 T 表位来设计的。在大肠杆菌中同时表达这三种抗原后，在小鼠和猪中测试了其免疫原性。最后在猪中还检测了与猪 IFN-α 联合表达的抗原。通过 ELISA 和 qPCR 评估免疫反应，并在攻毒后对肠道上皮组织进行组织病理学研究。小鼠和猪对嵌合抗原的 IgG 反应均增加。特别是，当猪 IFN-α 与细胞内劳森菌抗原共同给药时，抗体反应有显著差异。此外，在猪免疫后第一周检测到 il12 和 cd4 标记物的 mRNA，表明存在 Th1 型细胞免疫反应。oas2 基因表达的显著增强表明了猪 IFN-α 的作用。攻毒后的组织病理学分析显示，只有阴性对照组动物的胃肠道上皮细胞受到损伤。损伤与肠绒毛萎缩有关，观察到球细胞减少和淋巴细胞更多迁移。总的来说，我们的结果表明，候选疫苗引起了显著的体液和细胞免疫反应。此外，组织病理学分析表明，接种疫苗的动物对实验性细胞内劳森菌感染具有保护作用。这项研究是朝着开发针对细胞内劳森菌的第一种重组嵌合疫苗迈出的一步，代表了一种更快、更容易、更具成本效益的方法来对抗猪增殖性肠炎。
