Detection of antibody to toxoplasma gondii by immune adherence hemagglutination: an increased sensitivity by a lysate antigen

ABSTRACT

The antibody titers to Toxoplasma gondii in sera of 55 patients presumed to have toxoplasmosis were measured by immune adherence hemagglutination with both lysate antigen and whole organism. The results were compared with antibody tilers detected by immunofluorescent antibody tests performed with fluorescein-tagged anti-IgG and anti-IgM. The use of Toxoplasma lysate antigen significantly increased the sensitivity of the immune adherence hemagglutination test, particularly at higher serum dilutions, compared with the same test performed with whole organism. The immunofluorescent antibody test with anti-IgM demonstrated a greater number of seropositives, notably at antibody tilers of 512 to 1024 than a similar test with anti-IgG. Sera from 22 normal individuals were also tested by immune adherence hemagglutination with lysate and with whole Toxoplasma antigen. The latter showed no antibody liter, whereas the former detected low liters of antibody in 13 cases of which the majority ranged between two and eight The results obtained show that immune adherence hemagglutination with Toxoplasma gondii lysate antigen in microplate provides a simple and highly sensitive test for the serodiagnosis of toxoplasmosis