Characterization of monoclonal antibodies against broad bean stain and red clover mottle viruses.

Seven monoclonal antibodies (MoAbs) against red clover mottle comovirus (RCMV) and/or broad bean stain comovirus (BBSV) were characterized and used for epitope comparison of both viruses. All tested MoAbs, exclusively of IgG class, were directed to detergent-stable epitopes (metatopes and cryptotopes). Two of them were species-specific, while five others cross-reacted with both viruses to different extent. On the basis of the results of competitive ELISA, we assume different mutual position of common linear epitopes in RCMV and BBSV. They are more closely "packed up" on BBSV, while the BBSV-specific metatope is markedly dominant. The investigation of other RCMV and BBSV isolates by use of our MoAbs confirmed close relationship between both viruses and even showed that it is difficult to determine unambiguously the species of these isolates using immunochemical methods only.