Immunoglobulin G and immunoglobulin M enzyme-linked immunosorbent assays and defined toxoplasmosis serological patterns.
Enzyme-linked immunosorbent assay (ELISA) for toxoplasmosis was evaluated in serum samples presenting defined toxoplasmosis serological patterns, as determined by results in immunoglobulin (Ig)G and IgM immunofluorescence (IgG-IF, IgM-IF), hemagglutination, and complement fixation tests. ELISA was carried out with alkaline phosphatase-labeled anti-IgG and anti-IgM antibodies. Serum titer was expressed as the serum dilution end point determined by mere observation of color development in the test. A straight agreement was found between IgG-ELISA and IgG-IF titers, both in group A sera of ancient infections (patterns II and III) and group B sera of recent infections (pattern I). A similar agreement was found between IgG-ELISA and hemagglutination titers in group A sera, for which coincident IgG-IF and hemagglutination titers are also frequent. However, in group B sera, in spite of the same toxoplasma extract being used to sensitize both plastic surfaces and erythrocytes, IgG-ELISA titers were much higher than hemagglutination titers, in a way similar to that observed for IgG-IF titers. IgM-ELISA was positive in every group B serum, with higher titers than corresponding IgM-IF titers. Occasional low-titered positive IgM-ELISA results were seen for group A sera, sometimes due to IgM-antiglobulin antibodies. An easy test to perform, ELISA seems to be an adequate substitute for toxoplasmosis IF tests for routine purposes.
D003168:Complement Fixation Tests; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006386:Hemagglutination Tests; D006801:Humans; D007124:Immunoenzyme Techniques; D007070:Immunoglobulin A / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis*; D014123:Toxoplasmosis / Q000276:immunology*
D007070:Immunoglobulin A; D007074:Immunoglobulin G