Xu Kui, Zhao Qin, Wen Xintian, Wu Rui, Wen Yiping, Huang Xiaobo, Huang Yong, Yan Qigui, Han Xinfeng, Ma Xiaoping, Chang Yung-Fu, Cao Sanjie
Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.
Sichuan Science-observation Experiment Station of Veterinary Drugs and Veterinary Diagnostic Technology, Ministry of Agriculture, Chengdu, China.
PLoS One. 2018 Jan 26;13(1):e0191286. doi: 10.1371/journal.pone.0191286. eCollection 2018.
Actinobacillus pleuropneumoniae (APP) causes serious economic losses in the swine industry, and is the etiologic agent of porcine pleuropneumonia. In this study we have engineered a trivalent Apx fusion protein enclosed in outer membrane vesicles (Apxr-OMV) and studied its immunoprotective efficacy against APP serotypes 1 and 7 challenge in mice. The results showed that the IgG levels in the Apxr-OMVs immune group were significantly higher than those of the negative control (P < 0.05). Up-regulation of both Th1 (IFN-γ, IL-2) and Th2 (IL-4) cytokines were detected in splenocytes of Apxr-OMVs immune group. The survival rates 87.5% and 62.5% were observed against APP strain 1516 of serotype 7 and APP strain 2701 of serotype 1 in the groups of Apxr-OMVs immune group, respectively. Histopathological lesions of the pulmonary structure alveoli were found to be minimal in APX-OMV group challenged with APP serotypes 1 and 7. These results strongly indicated that engineered OMVs could effectively induce specific humoral or cellular immune responses. Moreover, Apxr-OMVs used as novel vaccine provides cross-protective immunity against different serotype 1 and 7 of APP infection in a mouse model. In contrast, the OMV-empty and PBS as negative controls or inactivated strain of APP-2701 and APP-1516 as positive controls for the animal study cannot provide protection or cross-protection.
胸膜肺炎放线杆菌（APP）给养猪业造成严重经济损失，是猪胸膜肺炎的病原体。在本研究中，我们构建了一种包裹在外膜囊泡中的三价Apx融合蛋白（Apxr-OMV），并研究了其对小鼠APP血清型1和7攻击的免疫保护效果。结果显示，Apxr-OMV免疫组的IgG水平显著高于阴性对照组（P<0.05）。在Apxr-OMV免疫组的脾细胞中检测到Th1（IFN-γ、IL-2）和Th2（IL-4）细胞因子均上调。在Apxr-OMV免疫组中，分别观察到针对血清型7的APP菌株1516和血清型1的APP菌株2701的存活率为87.5%和62.5%。在用APP血清型1和7攻击的APX-OMV组中，发现肺结构肺泡的组织病理学损伤最小。这些结果有力地表明，工程化的OMV能够有效诱导特异性体液或细胞免疫反应。此外，作为新型疫苗的Apxr-OMV在小鼠模型中对不同血清型1和7的APP感染提供交叉保护免疫。相比之下，作为动物研究阴性对照的空OMV和PBS，或作为阳性对照的APP-2701和APP-1516灭活菌株均不能提供保护或交叉保护。
