Expression and immunogenicity analysis of accessory colonization factor A from Vibrio alginolyticus strain HY9901

► The acfA was expressed and purified from Vibrio alginolyticus. ► Western blot showed protein recognition in different V. alginolyticus strains. ► The ACFA produced an observable antibody response in sera of the vaccinated fish. ► The RAG1 mRNA expression was up-regulated in thymus, head kidney and spleen. ► The fish vaccinated with ACFA were more tolerant against V. alginolyticus.