Department of Microbiology, Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand.
Fish Health Platform, Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand; National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120, Thailand.
Protein Expr Purif. 2024 Mar;215:106412. doi: 10.1016/j.pep.2023.106412. Epub 2023 Dec 15.
Aeromonas veronii is an emerging bacterial pathogen that causes serious systemic infections in cultured Nile tilapia (Oreochromis niloticus), leading to massive deaths. Therefore, there is an urgent need to identify effective vaccine candidates to control the spread of this emerging disease. TonB-dependent receptor (Tdr) of A. veronii, which plays a role in the virulence factor of the organism, could be useful in terms of protective antigens for vaccine development. This study aims to evaluate the potential use of Tdr protein as a novel subunit vaccine against A. veronii infection in Nile tilapia. The Tdr gene from A. veronii was cloned into the pET28b expression vector, and the recombinant protein was subsequently produced in Escherichia coli strain BL21 (DE3). Tdr was expressed as an insoluble protein and purified by affinity chromatography. Antigenicity test indicated that this protein was recognized by serum from A. veronii infected fish. When Nile tilapia were immunized with the Tdr protein, specific antibody levels increased significantly (p-value <0.05) at 7 days post-immunization (dpi), and peaked at 21 dpi compared to antibody levels at 0 dpi. Furthermore, bacterial agglutination activity was observed in the fish serum immunized with the Tdr protein, indicating that specific antibodies in the serum can detect Tdr on the bacterial cell surface. These results suggest that Tdr protein has potential as a vaccine candidate. However, challenging tests with A.veronii in Nile tilapia needs to be investigated to thoroughly evaluate its protective efficacy for future applications.
维氏气单胞菌是一种新兴的细菌病原体，可导致养殖尼罗罗非鱼（Oreochromis niloticus）发生严重的全身性感染，导致大量死亡。因此，迫切需要鉴定有效的疫苗候选物来控制这种新兴疾病的传播。维氏气单胞菌的 TonB 依赖性受体（Tdr）在该生物体的毒力因子中发挥作用，可作为疫苗开发的保护性抗原。本研究旨在评估 Tdr 蛋白作为新型亚单位疫苗用于防治尼罗罗非鱼维氏气单胞菌感染的潜力。从维氏气单胞菌中克隆了 Tdr 基因，并将其插入到 pET28b 表达载体中，随后在大肠杆菌菌株 BL21（DE3）中表达重组蛋白。Tdr 以不溶性蛋白的形式表达，并通过亲和层析进行纯化。抗原性测试表明，该蛋白可被感染维氏气单胞菌的鱼类血清识别。当尼罗罗非鱼用 Tdr 蛋白免疫时，与 0dpi 相比，在免疫后 7 天（dpi）时特异性抗体水平显著增加（p 值<0.05），并在 21dpi 时达到峰值。此外，用 Tdr 蛋白免疫的鱼血清中观察到细菌凝集活性，表明血清中的特异性抗体可检测到细菌细胞表面的 Tdr。这些结果表明 Tdr 蛋白具有作为疫苗候选物的潜力。然而，需要在尼罗罗非鱼中用维氏气单胞菌进行挑战性试验，以彻底评估其未来应用的保护效力。
