THE PRODUCTION AND CHARACTERIZATION OF MONOCLONAL-ANTIBODIES AGAINST ALTERNARIA-BRASSICAE (BERK.) SACC., THE CAUSE OF DARK LEAF AND POD SPOT IN OILSEED RAPE

Monoclonal antibodies (MAbs) were raised against homogenized spore ger mlings of Alternaria brassicae. SP2/0-Ag14 myeloma cells were fused wi th sensitized splenocytes 48 h after the final boost with antigen. Twe lve cell lines produced antibodies which recognized the isolate used f or immunization and a number of A. brassicae isolates from different p arts of the worm. However, only two cell lines, MAbs 34/7/G (IgG(1)) a nd 73/11/D (IgG(1)/IgM), were found to be species and isolate specific respectively for A. brassicae when tested against 19 isolates of rela ted and non-related fungi representing 13 fungal genera. Both species- specific antibodies recognized proteinaceous epitopes. A good correlat ion between the optical density in ELISA and the number of spores per well was found for antigen concentrations between 5 and 400 spore germ lings per well, when testing MAb 34/7/G in an indirect, alkaline phosp hatase-based ELISA. Results of wind tunnel experiments in which airbor ne A. brassicae spores were collected into ELISA wells showed a good c orrelation between the spore number when counted and the predicted spo re number when estimated by MAb 34/7/G in ELISA tests.