Li Hong-Jin, Yang Bin-Tong, Sun Yu-Feng, Zhao Tong, Hao Zhi-Peng, Gu Wei, Sun Meng-Xia, Cong Wei, Kang Yuan-Huan
Marine College, Shandong University, Weihai, 264209, China; College of Veterinary Medicine / College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China.
Marine College, Shandong University, Weihai, 264209, China; Shandong Fu Han Ocean Sci-Tech Co., Ltd, Haiyang, 265100, China.
Fish Shellfish Immunol. 2023 Apr;135:108659. doi: 10.1016/j.fsi.2023.108659. Epub 2023 Mar 1.
Vibrio mimicus (V. mimicus) is a pathogenic bacterium that causes diseases in humans and various aquatic animals. A particularly efficient way to provide protection against V. mimicus is through vaccination. However, there are few commercial vaccines against V. mimics, especially oral vaccines. In our study, two surface-display recombinant Lactobacillus casei (L. casei) Lc-pPG-OmpK and Lc-pPG-OmpK-CTB were constructed using L. casei ATCC393 as an antigen delivery vector, outer membrane protein K (OmpK) of V. mimicus as an antigen, and cholera toxin B subunit (CTB) as a molecular adjuvant; furthermore, the immunological effects of recombinant L.casei in Carassius auratus (C. auratus) were assessed. The results indicated that oral recombinant L.casei Lc-pPG-OmpK and Lc-pPG-OmpK-CTB stimulated higher levels of serum-specific immunoglobulin M (IgM) and increased the activity of acid phosphatase (ACP), alkaline phosphatase (AKP), superoxide dismutase (SOD), lysozyme (LYS), lectin, C3, and C4 in C. auratus, compared with control groups (Lc-pPG group and PBS group). Furthermore, the expression of interleukin-1β (IL-1β), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), and transforming growth factor-β (TGF-β) in the liver, spleen, head kidney, hind intestine and gills of C. auratus was significantly increased, compared with that in the controls. These results demonstrated that the two recombinant L. casei strains could effectively trigger humoral and cellular immunity in C. auratus. In addition, two recombinant L.casei strains were able to survive and colonize the intestine of C. auratus. Importantly, after being challenged with V. mimicus, C. auratus fed Lc-pPG-OmpK and Lc-pPG-OmpK-CTB exhibited greater survival rates than the controls (52.08% and 58.33%, respectively). The data showed that recombinant L. casei could elicit a protective immunological response in C. auratus. The effect of the Lc-pPG-OmpK-CTB group was better than that of the Lc-pPG-OmpK group, and Lc-pPG-OmpK-CTB was found to be an effective candidate for oral vaccination.
拟态弧菌是一种可导致人类和多种水生动物发病的致病细菌。预防拟态弧菌感染的一种特别有效的方法是接种疫苗。然而，针对拟态弧菌的商业疫苗很少，尤其是口服疫苗。在我们的研究中，以干酪乳杆菌ATCC393作为抗原递送载体，将拟态弧菌的外膜蛋白K（OmpK）作为抗原，霍乱毒素B亚基（CTB）作为分子佐剂，构建了两种表面展示重组干酪乳杆菌Lc-pPG-OmpK和Lc-pPG-OmpK-CTB；此外，还评估了重组干酪乳杆菌对鲫鱼的免疫效果。结果表明，与对照组（Lc-pPG组和PBS组）相比，口服重组干酪乳杆菌Lc-pPG-OmpK和Lc-pPG-OmpK-CTB可刺激鲫鱼产生更高水平的血清特异性免疫球蛋白M（IgM），并提高其酸性磷酸酶（ACP）、碱性磷酸酶（AKP）、超氧化物歧化酶（SOD）、溶菌酶（LYS）、凝集素、C3和C4的活性。此外，与对照组相比，鲫鱼肝脏、脾脏、头肾、后肠和鳃中白细胞介素-1β（IL-1β）、白细胞介素-10（IL-10）、肿瘤坏死因子-α（TNF-α）和转化生长因子-β（TGF-β）的表达显著增加。这些结果表明，这两种重组干酪乳杆菌菌株能够有效激发鲫鱼的体液免疫和细胞免疫。此外，两种重组干酪乳杆菌菌株能够在鲫鱼肠道内存活并定殖。重要的是，在用拟态弧菌攻毒后，投喂Lc-pPG-OmpK和Lc-pPG-OmpK-CTB的鲫鱼存活率高于对照组（分别为52.08%和58.33%）。数据表明，重组干酪乳杆菌可在鲫鱼中引发保护性免疫反应。Lc-pPG-OmpK-CTB组的效果优于Lc-pPG-OmpK组，且Lc-pPG-OmpK-CTB被发现是一种有效的口服疫苗候选物。
