Immune response of ayu against Vibrio anguillarum lipopolysaccharide.

Abstract

In order to investigate immune response of ayu Plecoglossus altivelis against Vibrio anguillarum lipopolysaccharide (LPS) by intraperitoneal injection, antibody production at various water tem-peratures and amount of the crude LPS that induce protective immunity were examined. Agglu-tinating antibody titer against formalin-killed cell and passive hemagglutinating antibody titer against crude LPS and pure LPS increased 1 week after immunization in the fish reared at 25°C and 3 weeks after the immunization in the fish reared at 15-20°C. The fish reared at 10°C showed lower titers at 5 weeks after immunization. Distinctly higher agglutinating antibody titer against formalin-killed cell was observed in the serum and mucus of the fish immunized with 0.05-0.50 mg of crude LPS than that of the control fish. Those immunized fish showed 100% survival rate after challenge by water born infection, while the control fish showed 13.3 %. From these results, it is concluded that ayu shows good immune response against V. anguillarum LPS at a range of 15-25°C and 0.05 mg of LPS per fish induces an enough immune protection against the infection.