title: Enzyme-linked immunosorbent assay for antibodies to Toxoplasma gondii polysaccharides in human toxoplasmosis.
abstract: A polysaccharide fraction from Toxoplasma gondii was adsorbed to polystyrene plates, and the enzyme-linked immunosorbent assay was performed (poly-ELISA) with peroxidase-labeled anti-immunoglobulin G and anti-immunoglobulin M antibodies. A comparison was made with a T. gondii total protein extract ELISA (protein ELISA) in serum samples presenting different toxoplasmosis serological patterns, as indicated by a battery of tests for toxoplasmosis. Very low titers and negative results were seen for immunoglobulin G poly-ELISA both for serum samples corresponding to ancient or transitional-period infections (serological patterns II and III) and for samples of recent or acute toxoplasmosis (pattern I). On the contrary, immunoglobulin M poly-ELISA furnished high titer results for pattern I sera, and a very close agreement of titers was seen between immunoglobulin M protein ELISA and immunoglobulin M poly-ELISA. When the polysaccharide fraction was added to pattern I sera, a complete blocking of immunoglobulin M antibody reactivity resulted only for poly-ELISA. In the same way, the total protein extract could completely block only reactivity for protein ELISA. In both cases, a limited decrease in titers was observed for respective heterologous assays.
mesh_terms: D000818:Animals; D000906:Antibodies / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D011134:Polysaccharides / Q000276:immunology*; D011506:Proteins / Q000276:immunology; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000276:immunology*
chemical_list: D000906:Antibodies; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D011134:Polysaccharides; D011506:Proteins