Hybridoma antibody immunoassays for the detection of parasitic infection: attempts to produce an immunodiagnostic reagent for a larval taeniid cestode infection.

Attempts have been made to produce discriminatory immunodiagnostic reagents for infections of sheep with the larval stages of Taenia hydatigena, Taenia ovis and Echinococcus granulosus. Using cells from mice hyperimmunized with T. hydatigena antigenic preparations for fusion, a hybridoma antibody which bound to T. hydatigena larval antigens, but not to T. ovis or E. granulosus larval antigens, was selected. A competitive radioimmunoassay using the labelled hybridoma antibody and a crude parasite antigen mixture was devised as an immunodiagnostic test for experimental T. hydatigena infection. Sera from sheep exposed to 1000 or more T. hydatigena eggs were unequivocally positive but sera from 2 sheep with a monospecific infection with T. ovis were also positive. Sera from E. granulosus-infected sheep were negative and, although the numbers of sera involved were small, such discrimination has not been achieved by previous serologic methods. The discussion emphasizes various difficulties which have been encountered in the development of highly sensitive as well as specific hybridoma-based immunodiagnostic reagents for the detection of larval cestode infections in sheep.