Monoclonal antibodies against potato virus A--competitive binding tests.

Six mouse monoclonal antibodies (MoAbs) against potato virus A (PVA) were tested. One of them (PVA 534) reacted only with complete virions and was apparently specific for epitopes dependent on quaternary structure. MoAb PVA 328 recognized the virus antigen only after its dissociation into subunits. MoAb PVA 328 must have reacted with a cryptotope of the antigen. MoAb PVA 151 and 290 appeared to be conformation independent and reacted with exposed regions on native virus particles as well as on the surface of dissociated coat protein subunits. Two other MoAbs (PVA 187 and 634) did not recognize subunits or the virions adsorbed directly to the microtiter plate. This seems to be an evidence of metatope existence. The results of competitive binding tests combined with the reaction patterns of individual MoAbs to different potyviruses indicate that the MoAbs are specific for 6 distinct epitopes.