Monoclonal Antibodies Specific for Xanthomonas campestris Bacteria Pathogenic on Wheat and other Small Grains, in Comparison with Polyclonal Antisera

4 hybridoma cell lines (named F1-AA9-D9, F1-AB3-B6, F1-BC7-C1 and F2-CA7-F11) secreting monoclonal antibodies to Xanthomonas campestris pv. undulosa were produced by fusing splenocytes from immunized Lou rats with IR983F myeloma cells. Whole cells were used both as immunogen and as antigen in ELISA and indirect immunofluorescence tests.
The monoclonal antibodies produced reacted positively with X. c. pv. undulosa (38 strains), pv. translucens (3), pv. hordei (3), pv. cerealis (2) and pv. secalis (1).
Strains from other pathovars ( X. c. pv. arrhenatheri, pv. graminis, pv. manihotis, pv. oryzicola, pv. poae and pv. pruni ) and from other species ( X axonopodis, X. ampelina ) and genus ( Pseudomonas, Erwinia, Clavibacter , wheat saprophytic strains) gave a negative reaction. In comparison, seven polyclonal rabbit antisera showed to be less specific: they reacted with unrelated X. campestris pathovars as well as with Pseudomonas strains. Nevertheless, the use of phenol-treated cells in Ouchterlony double immunodiffusion could reduce the effect of cross-reaction for antisera.
The detection of X. c. pv. undulosa by indirect immunofluorescence on infected wheat seed lots has already been applied with success.