The in vivo roles of galectin-2 from Nile tilapia (Oreochromis niloticus) in immune response against bacterial infection.

Our previous study has recorded that the recombinant protein of Nile tilapia (Oreochromis niloticus) galectin-2 (rOnGal-2) can enhance immune response against Streptococcus agalactiae (S.agalactiae) infection in vitro. In this study, we further explored the effects of OnGal-2 in immune response against bacterial infection in vivo. The administration of rOnGal-2 could improve serum antibacterial activity (ALKP, ACP, and LZM) and antioxidant capacity (CAT, POD, and SOD). After S. agalactiae infection, rOnGal-2 injection could reduce bacterial burden and decrease tissue damage in head kidney, spleen, and liver of tilapia. Also, rOnGal-2 regulated the inflammatory-related genes expression including IL-6 , IL-8 and IL-10 during bacterial infection. Furthermore, rOnGal-2 administration could increase the relative percentage survival of tilapia infected with S.agalactiae. Taken together, our results indicate that OnGal-2 can protect fish from bacterial infection through reducing bacterial burden, impairing tissue damage and modulating anti-bacterial immune response, which also can be applied as a potential vaccine adjuvant in O.niloticus culture. • The administration of rOnGal-2 in vivo improved Nile tilapia serum antibacterial activity and antioxidant capacity. • rOnGal-2 treatment could reduce bacterial burden and decrease tissue damage post S.agalactiae infection. • rOnGal-2 could regulate the inflammatory-related genes expression during bacterial infection. • rOnGal-2 administration could increase the relative percentage survival of tilapia infected with S.agalactiae. [ABSTRACT FROM AUTHOR]