CHARACTERIZATION OF A 200 KDA GLYCOPROTEIN (CS-GP200) ON THE PATHOGENIC PISCINE HEMOFLAGELLATE CRYPTOBIA-SALMOSITICA

The 200 kDa antigenic doublet of the pathogenic haemoflagellate Crypto bia salmositica Katz, 1951, was detected using a monoclonal antibody ( MAb-001) in 1-dimensional SDS-PAGE. This antigenic doublet is a glycop rotein since it was susceptible to both protease K and to sodium m-per iodate oxidation and is designated Cs-gp200. It has a PI (isoelectric point) value of about 5.5 (using 2-dimensional gel electrophoresis). I t migrated faster under reducing conditions than under nonreducing con ditions and was partitioned into the aqueous phase in Triton X-114 pha se separation. It is a secretory-excretory product since it was detect ed in a non-protein culture medium with C. salmositica. These results suggest that the Cs-gp200 is a glycoprotein consisting of carbohydrate determinants and conformational polypeptide with internal disulphide bonds. It is a hydrophilic antigen, is a secretory product of the para site, and plays a important role in antibody elicitation in immunized fish.