Characterisation and reactivity of a glycidic antigenic component in Toxoplasma gondii.

Toxoplasma gondii is composed of a complex antigenic mosaic and some antigenic fractions are of major diagnostic interest. We studied an antigenic fraction with molecular weight < 17 kda, identified by SDS-PAGE 15% and immunoblotting. This fraction could be easily extracted from the whole antigen with phenol/CH-Cl3 and its analysis showed a mainly carbohydrate composition. With immunoblotting this fraction showed strong reactivity with specific IgM and IgG in early-acute infection; IgM reactivity disappears or is much less marked in chronic acquired infection. Extraction with phenol/CHCl3 allows this fraction to be used as an antigen in other diagnostic methods.