DEVELOPMENT OF AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR ANALYSIS OF SPORIDESMIN-A AND ITS METABOLITES IN OVINE URINE AND BILE

Monoclonal and polyclonal antibodies have been produced for the development of competitive enzyme-linked immunosorbent assays for sporidesmin A, the mycotoxin that causes facial eczema in grazing livestock. Hemisuccinyl derivatives of sporidesmin conjugated to a number of proteins were used as immunizing and coating antigens. Two immunoassays have been developed. Each detects the presence of a different region of the sporidesmin molecule, therefore allowing the two major sporidesmins found in grass or in culture to be distinguished as well as allowing the detection of metabolites in ovine urine and bile. An analytical procedure that did not include organic solvent extraction was developed so that water-soluble metabolites would also be detected. Matrix effects occurring in the immunoassay of bile have been overcome by dilution of samples in 1% Tween 20 followed by heat treatment at 70 degrees C for 30 min. Sporidesmin A in bile measured by immunoassay was compared with that measured by HPLC. The coefficient of determination R(2) was 0.97.