ANTIGENIC CHARACTERIZATION OF SEROGROUP-A OF INFECTIOUS PANCREATIC NECROSIS VIRUS WITH 3 PANELS OF MONOCLONAL-ANTIBODIES

Monoclonal antibodies (MAbs) were produced against three serotypes of infectious pancreatic necrosis virus (IPNV): A1 (LWVRT 60-1, U.S.A.), A2 (d'Honnincthun, France) and A9 (Jasper, Canada). Each panel of MAbs (identified as LW, HF and JA) was analysed by ELISA with the 10 propo sed serotypes of IPNV and their specificity defined by immunoprecipita tion and Western immunoblotting analysis. A first group of MAbs, direc ted against the outer capsid protein VP2, reacted with linear or confo rmational epitopes. A second group of MAbs, directed against the inter nal protein VP3, reacted with linear epitopes. There was no relationsh ip between the neutralizing property of anti-VP2 MAb and the configura tion of the epitope that it recognized. The MAbs were used for antigen ic characterization of serogroup A. Each panel of MAbs showed a charac teristic pattern of reactivity. The European HF series was predominant ly cross-reactive and detected conserved epitopes among the 10 serotyp es for both VP2 and VP3. The North American LW and JA series identifie d a group of conserved epitopes on VP3 and new specific epitopes on VP 2 and VP3. The higher variability observed for VP2 in comparison with VP3 is one example of how external pressures may promote natural selec tion of those epitopes required for virus survival. Our results are co nsistent with an ancestral relationship of the European to the North A merican strains, the latter having developed new antigenic determinant s upon evolution in their new geographical location.