Preparation and specificity of antibodies against coat proteins of broad bean stain virus.

Mouse polyclonal antibodies were prepared against broad bean stain virus (BBSV, Comovirus group) and its coat protein subunits, large (L) and small (S) protein. These subunits were less immunogenic than native virus. Antibodies against L protein (Anti-L) and native virus (Anti-BBSV) did not react in immunoblots with S protein, but Anti-BBSV antibody reacted with S protein in plate-trapped antigen ELISA. Anti-S antibodies did not react with the related red clover mottle comovirus (RCMV), but Anti-L and Anti-BBSV antibodies reacted with RCMV similarly to BBSV. We assume that all the linear epitopes of the BBSV S protein are hidden in the native virions and the antigenic similarity between BBSV and RCMV is based mainly on their common linear L-specific epitopes.