Protective efficacy evaluation of immunogenic protein AHA_3793 of Aeromonas hydrophila as vaccine candidate for largemouth bass Micropterus salmoides

• Published in: Journal of oceanology and limnology 2023, Vol.41 (1), p.392-400
• Main Authors: Yang, Shun, Mkingule, Idefonce, Liu, Long, Chen, Wenqi, Yuan, Xiangyu, Ma, Zixuan, Liang, Liang, Qian, Shichao, Huang, Mengmeng, Fei, Hui
• Format: Article
• Language: English
• Subjects: Aeromonas hydrophila; Analysis; Antibodies; Aquaculture and Fisheries; Bass; CD4 antigen; Defence mechanisms; Disease control; Earth and Environmental Science; Earth Sciences; Economic impact; Effectiveness; ELISA; Enzyme-linked immunosorbent assay; Fish; Freshwater fishes; Immune response; Immune response (humoral); Immune system; Immunity; Immunization; Immunogenicity; Major histocompatibility complex; Mass spectrometry; Mass spectroscopy; Membrane proteins; Micropterus salmoides; Nucleotide sequence; Oceanography; Outer membrane proteins; Pathogens; Proteins; Serum; Survival; Vaccines; Western blotting; Whitefish
• ISSN: 2096-5508; 2523-3521
• DOI: 10.1007/s00343-022-1326-8

Aeromonas hydrophila is a Gram-negative pathogen that can infect various fish, including largemouth bass ( Micropterus salmoides ), which have caused huge economic losses. In present study, largemouth bass anti- A. hydrophila antibodies were produced, then a highly immunogenic outer membrane proteins, AHA_3793, was identified by combined western blotting and mass spectrometry analysis. Moreover, AHA_3793 was expressed, and its immunogenicity was further verified by western blotting. Subsequently, the protective efficacy of AHA_3793 were evaluated in largemouth bass. The results showed that rAHA_3793 could produce a relative percentage survival (RPS) of 61.76% for largemouth bass against A. hydrophila challenge. ELISA analysis showed the specific serum antibodies of largemouth bass against rAHA_3793 and A. hydrophila in vaccinated group in weeks 4 and 5 after immunization were significantly higher than those in control group, which suggested that rAHA_3793 induced production of specific serum antibodies against rAHA_3793 and A. hydrophila . The qRT-PCR analysis showed that expressions of CD4-2 and MHC IIα were also significantly up-regulated after immunization. These results collectively demonstrated that rAHA_3793 could induce a strong humoral immune response of largemouth bass, and then produce high immune protection effects against A. hydrophila infection.