Detection of specific antibodies to Toxoplasma gondii by a competitive enzyme immunoassay using a monoclonal antibody against the P30 antigen.

An inhibition EIA using a monoclonal antibody against the major P30 Toxoplasma gondii surface protein was designed for detection of specific antibodies in human sera. The assay was based on the inhibition of binding of peroxidase labelled monoclonal antibody to Toxoplasma gondii crude antigen coated plates by the corresponding antibodies present in human sera. This rapid and simple assay was compared to indirect immunofluorescence, direct agglutination and an immunosorbent agglutination assay using 435 human sera. The specificity and sensitivity were 100% and 97% respectively. This test was found to be as sensitive as the dye test.