State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, People's Republic of China.
Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, 130025, People's Republic of China.
Microb Cell Fact. 2022 Jun 13;21(1):114. doi: 10.1186/s12934-022-01839-9.
Aeromonas veronii (A. veronii) is a pathogenic that can infect human, animal and aquatic organisms, in which poses a huge threat to the health of many aquatic organisms such as Cyprinus carpio. In this study, Lactobacillus casei (L. casei) strain CC16 was used as antigen deliver carrier and fused with cholera toxin B subunit (CTB) as an adjuvant to construct the recombinant L. casei pPG-Aha1/Lc CC16(surface-displayed) and pPG-Aha1-CTB/Lc CC16(surface-displayed) expressing Aha1 protein of A. veronii, respectively. And the immune responses in Cyprinus carpio by oral route was explored. Our results demonstrated that the recombinant strains could stimulate high serum specific antibody immunoglobulin M (IgM) and induce a stronger acid phosphatase (ACP), alkaline phosphatase (AKP), C3, C4, lysozyme (LZM), Lectin and superoxide dismutase (SOD) activity in Cyprinus carpio compared with control groups. Meanwhile, the expression of Interleukin-10 (IL-10), Interleukin-1β (IL-1β), Tumor Necrosis Factor-α (TNF-α), immunoglobulin Z1 (IgZ1) and immunoglobulin Z2 (IgZ2) in the tissues were significantly upregulated compared with Lc-pPG or PBS groups, indicating that humoral and cell immune response were triggered. Additionally, recombinant L. casei could survive and colonize in fish intestine. Significantly, recombinant L. casei provides immune protection against A. veronii infection, which Cyprinus carpio received pPG-Aha1-CTB/Lc CC16 (64.29%) and pPG-Aha1/Lc CC16 (53.57%) had higher survival rates compared with the controls. Thus, we demonstrated that recombinant pPG-Aha1/Lc CC16 and pPG-Aha1-CTB/Lc CC16 may be the promising strategy for the development of an oral vaccine against A. veronii.
维氏气单胞菌（Aeromonas veronii，A. veronii）是一种能够感染人类、动物和水生生物的病原体，对许多水生生物的健康构成了巨大威胁，如鲤鱼（Cyprinus carpio）。在本研究中，使用干酪乳杆菌（Lactobacillus casei，L. casei）菌株 CC16 作为抗原传递载体，并与霍乱毒素 B 亚单位（cholera toxin B subunit，CTB）融合作为佐剂，构建了分别表达维氏气单胞菌 Aha1 蛋白的重组干酪乳杆菌 pPG-Aha1/Lc CC16（表面展示）和 pPG-Aha1-CTB/Lc CC16（表面展示）。并探讨了其经口免疫鲤鱼的免疫应答。结果表明，重组菌能够刺激鲤鱼产生高血清特异性免疫球蛋白 M（immunoglobulin M，IgM），并诱导更强的酸性磷酸酶（acid phosphatase，ACP）、碱性磷酸酶（alkaline phosphatase，AKP）、C3、C4、溶菌酶（lysozyme，LZM）、凝集素和超氧化物歧化酶（superoxide dismutase，SOD）活性。同时，与 Lc-pPG 或 PBS 组相比，组织中白细胞介素 10（interleukin-10，IL-10）、白细胞介素 1β（interleukin-1β，IL-1β）、肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）、免疫球蛋白 Z1（immunoglobulin Z1，IgZ1）和免疫球蛋白 Z2（immunoglobulin Z2，IgZ2）的表达显著上调，表明触发了体液和细胞免疫反应。此外，重组干酪乳杆菌能够在鱼肠道中存活和定植。值得注意的是，重组干酪乳杆菌对维氏气单胞菌感染提供了免疫保护，与对照组相比，鲤鱼接受 pPG-Aha1-CTB/Lc CC16（64.29%）和 pPG-Aha1/Lc CC16（53.57%）的存活率更高。因此，我们证明了重组 pPG-Aha1/Lc CC16 和 pPG-Aha1-CTB/Lc CC16 可能是开发针对维氏气单胞菌的口服疫苗的有前途的策略。
