MONOCLONAL-ANTIBODIES TO THE GLYCOPROTEIN AND NUCLEOPROTEIN OF INFECTIOUS HEMATOPOIETIC NECROSIS VIRUS (IHNV) REVEAL DIFFERENCES AMONG ISOLATES OF THE VIRUS BY FLUORESCENCE, NEUTRALIZATION AND ELECTROPHORESIS

Monoclonal antibodies were produced to the glycoproteins and nucleoproteins of several isolates of infectious hematopoietic necrosis virus (IHNV). Antibodies were selected for cloning by enzyme-linked immunosorbent assay (ELISA), neutralization tests, indirect fluorescence and by their ability to immunoprecipitate viral proteins. To test the utility of this group of monoclonal antibodies for virus typing, 17 strains of IHNV from different geographical regions, years, and from different fish stocks were analyzed by: immunoprecipitation followed by polyacrylamide gel electrophoresis, indirect fluorescence with 27 monoclonal antibodies, and serum neutralization with 6 monoclonal anti-glycoprotein antibodies. Using SDS gel electrophoresis, minor variations in nucleoprotein molecular weights were noted among the 17 selected isolates. Serum neutralization of the 17 isolates with 2 of the antiglycoprotein antibodies, 3GH127B and 3GH92A, divided the 17 selected isolates into 2 groups, those which were neutralized with both antibodies, and those which were not. Typing by indirect fluorescence with the antibodies, however, indicated that antigenic variation existed between isolates. Twenty-eight older isolates of IHNV, previously classified into electrophoretic types I to V, and 10 recent isolates were also tested by immunofluorescence for reaction with the monoclonal antibodies.