The use of monoclonal antibody-based ELISAs to monitor chemotherapeutic effects in the bovine-Onchocerca gibsoni drug screen

Three monoclonal antibodies directed towards antigens of Onchocerca gibsoni were used in antigen detection ELISAs to detect parasite antigens in sera from 100 cattle infected with O. gibsoni, in trials with the filaricidal compounds CGP 6140, CGP 20309, CGP 20376, CGP 21833, CGP 24589 and CGP 26702. Measurable levels of parasite antigens were highly variable, both within and between treatment and control groups of animals, with no consistent trends which related to time after treatment, micro or macrofilaricidal effects against O. gibsoni, or dose rate for any of the compounds used. It was concluded that these assays were unsuitable as a method of identifying drug-induced damage to O. gibsoni following the administration of these compounds. A detailed protocol for selecting suitable assays is discussed.