INDIRECT FLUORESCENT ANTIBODY METHOD IN SERODIAGNOSIS OF TOXOPLASMOSIS

Abstract

The principle of the indirect fluorescent antibody-staining procedure was adapted for use in the serodiagnosis of toxoplasmosis and the technique compared with other serological tests most commonly employed at present.The results obtained with normal and immune rabbit sera as well as human patients' sera indicate that the indirect fluorescent antibody test for toxoplasmosis is specific in a degree comparable to the complement fixation test, and is sensitive enough for routine laboratory use, its sensitivity being somewhat higher than that of the complement fixation test. The Sabin–Feldman dye test gave positive results with human sera from cases clinically unrelated to toxoplasmosis much more frequently and usually in higher titers than did the complement fixation and the fluorescent antibody tests. On the other hand, the dye test showed a few negative results on sera for which the other tests proved to be positive. The indirect fluorescent antibody test for toxoplasmosis is safer and simpler to perform than the dye test, as living organisms are not used in the test, and prepared smears of killed toxoplasma suspension on cover slips can be kept antigenically active in the frozen state for at least 6 months.The indirect fluorescent antibody test for toxoplasmosis is recommended for use in the serodiagnosis of toxoplasmosis either as a single test or as a supplementary test for checking complement fixation negative sera or the results obtained by the dye test.