STUDIES ON ANTIGENIC RELATEDNESS OF CLASSIC AND VARIANT STRAINS OF INFECTIOUS BURSAL DISEASE VIRUSES

Antigenic relatedness of six classic and variant strains of serotype 1 infectious bursal disease virus (IBDV) and one serotype 2 IBDV was in vestigated by Western blotting and enzyme-linked immunosorbent assay ( ELISA) using polyclonal, monoclonal, and monospecific antibodies to si ngle viral proteins (VP2 and VP3). All virus strains cross-reacted sim ilarly, and the viruses were not distinguishable from each other by EL ISA or Western blot analysis performed with polyclonal or non-neutrali zing monoclonal and monospecific antibodies. Non-neutralizing antibodi es against the VP2 (40 kilodaltons) reacted strongly with VP2 of class ic and variant strains of serotype 1 and reacted weakly with VP2 of se rotype 2 OH strain. This indicated that common antigens were recognize d and that these epitopes were not strictly dependent on the native st ructure of the virus.