AUTHOR=Zhang Yilin , Zhang Ziyu , Zhang Jinxia , Huang Yucong , Jian Jichang , Cai Shuanghu 

TITLE=A live attenuated strain of HY9901ΔdctP provides protection against Vibrio alginolyticus to the pearl gentian grouper (♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatus)

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.907407

DOI=10.3389/fmars.2022.907407

ISSN=2296-7745

ABSTRACT=In recent decades, vibriosis caused by Vibrio alginolyticus has become severely threat to the global mariculture industry. It is an urgent need for an effective vaccine to alleviate this unoptimistic situation. In this study, we evaluated the safety, immunoprotection and specific & non-specific immune response effect of ΔdctP strain as a live-attenuated vaccine to pearl gentian grouper (♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatu). The results demonstrate that the safety dose of ΔdctP was ≤1.0 ×106 CFU in pearl gentian grouper. The relative percent survival of the pearl gentian grouper challenged with the ΔdctP mutant strain by intraperitoneal injection reached 74.4%, which was significantly higher than that of control group. Meanwhile, the expression level of immune-relative genes, including IgM, IL-1β, IL-8, IL-10, MHC-Iα, MHC2, TNF-α, TLR3 and CD4, up-regulated in liver, spleen and head kidney within 28 d post-vaccination. Moreover, specific antibody IgM, total serum protein as well as activities of catalase, superoxide dismutase and lysozyme in serum were significantly up-regulated in vaccinated groupers compared with those in control. Collectively, ΔdctP could be used as a live-attenuated vaccine candidate against V. alginolyticus infection in pearl gentian grouper.