BIOLOGICAL CHARACTERIZATION OF A MONOCLONAL-ANTIBODY AGAINST A SURFACE-MEMBRANE ANTIGEN ON CRYPTOBIA-SALMOSITICA KATZ, 1951

A monoclonal antibody (IgG 1) (designated as MAb-001) was produced aga inst the pathogenic haemoflagellate Cryptobia salmositica Katz. The an tibody agglutinated live parasites under in vitro conditions. Live C. salmositica, incubated with MAb-001 at 10 degrees C, did not multiply and were dead within 4 weeks in culture. About 50% of juvenile rainbow trout, Oncorhynchus mykiss (Walbaum), inoculated intraperitoneally wi th C. salmositica, incubated in MAb-001 prior to inoculation, did not become infected, while in adult rainbow trout, the peak parasitaemia w as reduced. These results indicate that MAb-001 is a protective monocl onal antibody and the antigen it recognizes is located on the surface membrane of C. salmositica. The antibody also inhibits multiplication and affects viability of the parasite under in vitro conditions.