Production and preliminary characterization of monoclonal antibodies to Saprolegnia parasitica

Murine monoclonal antibodies (IgM and IgG isotypes) produced against Saprolegnia parasitica ATCC 52719 a common oomycete pathogen of fishes, recognized all S. parasitica isolates when used in an indirect immunofluorescence assay. The S. parasitica isolates, originating from diseased fish, had titres that were equivalent to or higher than isolates of the closely related taxon, Saprolegnia diclina, which was cultured from water. The S. parasitica isolates had higher titres than more distantly related oomycetes (Saprolegnia australis and Aphanomyces sp.) and non-oomycete fungi. Thus, reaction of fungi with the monoclonal antibodies was directly related to their taxonomic relationship to S. parasitica.