Characterization of Toxoplasma gondii antigens that react with human immunoglobulin M and immunoglobulin G antibodies

Abstract

Studies were performed to define the nature of the Toxoplasma gondii antigens that are recognized by human immunoglobulin M (IgM) and IgG antibodies. Both IgM and IgG antibodies were found to be directed mainly against T. gondii membrane antigens in sera obtained from patients with acute toxoplasmosis. Treatment of the membrane preparation with DNase, RNase, or lipase had no apparent effect on the reactivity of the membrane antigens with IgM and IgG antibodies. Lipids isolated from tachyzoites were not recognized by either IgM or IgG antibodies. Exposure of T. gondii membranes to heat, proteolysis, or oxidation with sodium periodate decreased the reactivity of the membrane preparations with both IgM and IgG antibodies. A preparation of T. gondii proteins and polysaccharides were recognized by both immunoglobulin classes. T. gondii polysaccharides reacted with human IgG antibodies produced during both the acute and chronic phases of the infection. We concluded that, after infection with T. gondii, IgM and IgG antibodies are elicited in response to both protein and carbohydrate constituents of the invading parasite.

Strain-specific antigens of Toxoplasma gondii

“…Thus, certain native antigens (i.e., P22 and P30) of the laboratory-maintained RH strain may have lost their glycosylated chains and only the core protein antigen persists after numerous serial passages. This hypothesis has been supported in part by previous investigators who have shown that RH strain T. gondii expresses low amounts of carbohydrates on its surface as determined by periodic acid staining and lectin binding (8,15,16,19). We have observed a high affinity of strain C for a number of lectins (unpublished data).…”

A novel igm‐indirect hemagglutination test for the serodiagnosis of acute toxoplasmosis

“…We are now performing the identification of the heat-stable WPAE antigens involved in the M-Toxo-IHA test by an immunoblotting technique in order to compare with those already identified by different authors (12,15,36,37) as having serodiagnostic potential of acute toxoplasmosis.…”

“…Having in mind that IgM-Ab react mainly with polysaccharide, glycoprotein, or lipopolysaccharide antigens in bacterial and protozoan infections (14)(15)(16)(17), we tried to develop a reagent for the IHA testing by coating formalinized erythrocytes with heat-stable components of an alkaline-solubilized extract of T. gondii.…”

Subcellular localization and quantitative analysis of Toxoplasma gondii target antigens of specific immunoglobulins G, M, A, and E

“…d. When the immunolabeling between the membrane complex and the rhoptries are compared, there is no statistically significant difference for IgG and IgM isotypes (P > 0.05), but there is for IgA (P < 0.01). Naot et al (1983), both IgG and IgM antibodies produced during the acute stage of infection with T. gondii react preferentially with T. gondii membranes and less strongly with cytoplasmic antigens. P30, the major surface antigen [also present inside the rhoptries )1, induces a polyisotypic response to IgG, IgM, IgA, and IgE.…”