Characterization of Monoclonal Antibodies Raised against Phytophthora capsici

Characterization of three monoclonal antibodies (MAs: PC1A6, PC1B2 and PC1C5) raised against mycelial suspension of Phytophthora capsici was analyzed. The reactivities of mycelial materials to MAs were tested by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Epitopes recognized by PC1A6, PC1B2 and PC1C5 were different from each other. PC1C5 showed genus specific reactivities in the ELISA test and Western blot analysis. This suggested that Phytophthora isolates studied had a common epitope recognized by PC1C5. Results of Western blot analysis showed that the epitopes recognized by PC1A6, PC1B2 and PC1C5 might be placed on several components with different molecular weight which were separated by SDS-PAGE. The immunogenic antigens of each MA were eluted at the first peak containing both polysaccharides and proteins on a Sephadex G-200 column. Mycelial suspension from P. capsici was treated with proteinase K and periodate, and then assayed by ELISA, DIBA and Western blot analysis. The results suggested that PC1A6 recognized a carbohydrate epitope and, that PC1B2 and PC1C5 recognized protein epitopes.