Demonstration of Serological Relationships among Isolates of Barley Yellow Dwarf Virus by Using Polyclonai and Monoclonal Antibodies

Hybridomas secreting monoclonal ntibodies against hree isolates of barley yellow dwarf virus (BYDV) were established. Two monoclonal antibody preparations were generated against the MAV isolate, one against RPV and six against P-PAV. None of the monoclonal antibody preparations reacted with healthy host components. Reactions of monoclonal ntibodies, or unlabelled polyclonal antisera, in an indirect enzyme-linked immunosorbent assay (ELISA) indicated that all three virus isolates share a common epitope. BYDV particles dissociated when incubated in carbonate-bicarbonate coating buffer at pH 9.6 but could be stabilized by prior dialysis against 2 % formaldehyde or 2 % glutaraldehyde. In indirect ELISA, unlabelled polyclonal antisera bound to both stabilized and dissociated particles of homologous and heterologous BYDV isolates. However, conjugated polyclonal antisera were incapable of binding to dissociated particles or to stabilized particles of heterologous isolates. Experiments with monoclonal antibodies in a competition ELISA indicated the presence of at least two epitopes on the coat protein of P-PAV