Production of Monoclonal Antibodies to Potato Virus Y Helper Component-Protease and Their Use for Strain Differentiation . TOMAS CANTO, Centro de Investigaciones Biol6gicas, C/. Velazquez, 144. 28006, Madrid. PETER ELLIS and GERDA BOWLER, Agriculture Canada Research Station, 6660 NW Marine Drive, Vancouver, BC V6T 1X2; and D. LOPEZ-ABELLA, Centro de Investigaciones Biologicas, C/. Velazquez, 144. 28006, Madrid. Plant Dis. 79:234-237. Accepted for publication 25 October 1994. Copyright 1995 Department of Agriculture and Agri-Food, Government of Canada. DOI: 10.1094/PD-79-0234.

Ten monoclonal antibodies (MAbs) and a rabbit antiserum containing polyclonal antibodies (PAbs) were prepared against helper component-protease (HC-Pro) purified from plants infected with a non-aphid-transmissible strain of potato virus Y (PVY-O NAT). All MAbs reacted with PVY HC-Pro in two enzyme-linked immunosorbent assay (ELISA) protocols, and seven were useful for Western blot analysis. Six MAbs and the PAbs were compared in direct antigen-binding ELISA for reactivity with 22 isolates of PVY, potato virus A (PVA), tobacco etch virus (TEV), and pepper mottle virus (PepMoV). None of the MAbs or the PAbs reacted with PVA or TEV HC-Pro. The immunoreactivity of one MAb was similar to the PAbs, reacting with all 22 PVY isolates and with PepMoV, but failing to react with PVA and TEV HC-Pro. Another MAb reacted with all of the common strains of PVY (PVY0) and a stipple-streak strain of PVY (PVYC) but not with any of the tobacco veinal necrosis strains (PVYN). The other MAbs could be used to differentiate a subgroup within the PVY° and PVYN strain groups. These MAbs proved useful for identifying strains of PVY.