Improvements to the competitive ELISA for detection of antibodies to Brucella abortus in cattle sera.

This paper reports improvements in the competitive ELISA (cELISA) for the detection of serum antibodies to Brucella abortus through modification of the coating of antigen and of the enzyme labelling of the monoclonal antibody conjugate. The covalent linkage of poly-L-lysine to the o-polysaccharide antigen of Brucella abortus enhanced its binding to the polystyrene matrix which resulted in a more efficient and reliable cELISA. Optimal discrimination between vaccinated and infected cattle was achieved by adjustment of the ratio between the monoclonal antibody used in the cELISA and the horseradish peroxidase. Both modifications resulted in a refined, more efficient and reliable cELISA with potential as a routine serodiagnostic assay for Brucellosis.