Protective efficacy evaluation of immunogenic protein AHA_3793 of as vaccine candidate for largemouth bass .

is a Gram-negative pathogen that can infect various fish, including largemouth bass (), which have caused huge economic losses. In present study, largemouth bass anti- 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 challenge. ELISA analysis showed the specific serum antibodies of largemouth bass against rAHA_3793 and 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 . The qRT-PCR analysis showed that expressions of and 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 infection.