Fimbrial-Specific Monoclonal Antibody-Based ELISA for European Potato Strains of Erwinia chrysanthemi and Comparison to PCR

Abstract

A murine hybridoma cell line, named 6A6, was developed to produce monoclonal antibodies for serological detection of European potato strains of Erwinia chrysanthemi. The monoclonal antibodies were of the immunoglobulin G2b type and were shown to react with a fimbrial antigen by immuno-gold electron microscopy, and with the fibrillin protein by Western blotting. In enzyme-linked immunosorbent assay (ELISA), the monoclonal antibody reacted with all but two strains of E. chrysanthemi isolated from potato. One non-reactive strain originated from Australia and therefore was likely a different biovar, and the other strain was of unknown origin. The monoclonal antibody also reacted with 20 out of 36 strains of E. chrysanthemi isolated from hosts other than potato. A triple-antibody ELISA test utilizing monoclonal antibody 6A6 successfully detected E. chrysanthemi in infected potato stems and tubers but sensitivity was limited to about 107 CFU/ml, compared to a sensitivity of 103 CFU/ml for a polymerase chain reaction test using published primers directed to the pectate lyase gene.