DEVELOPMENT OF MONOCLONAL-ANTIBODIES AGAINST THE FUNGI OF THE ASCOCHYTA COMPLEX

Two monoclonal antibodies (MAbs) were produced against soluble antigen s from the 'Ascochyta complex' fungi. Specificity of MAbs was tested b y ELISA using antigen-coated wells. MAbs secreted by the monoclonal hy bridoma cell line JIM 44 recognized epitopes present in the antigen pr eparations from Mycosphaerella pinodes and Phoma medicaginis var. pino della, but not those present in preparations from Ascochyta pisi. At h igh tissue culture supernatant concentration, MAbs produced by the mon oclonal line JIM 45 recognized epitopes from all three fungi, however, on dilution of MAb the antigens from A. pisi recognized preferentiall y to those from M. pinodes and P. medicaginis var. pinodella. On the b asis of hear and periodate treatment of the antigens from the three fu ngi it can be concluded that the epitope recognized by JIM 44 is carbo hydrate in nature, whereas that recognized by JIM 45 is proteinaceous in nature, carried on a glycoprotein antigen. Antigen preparations fro m other fungi, including other pea pathogens, non-pathogens associated with pea and other fungi closely related to the 'Ascochyta complex', were not detected with either of the two MAbs. Antigen preparations fr om peas could be used to differentiate healthy and infected seeds in a dot-blot assay, therefore indicating the potential of using the MAbs in the development of a diagnostic test for infection of Pisum seeds b y the 'Ascochyta complex' fungi.