Serodiagnosis of recently acquired Toxoplasma gondii infection using an enzyme-linked immunosorbent assay with a combination of recombinant antigens

An enzyme-linked immunosorbent assay (ELISA) using four recombinant antigen s of Toxoplasma gondii (rP22, rP25, rP29, and rP35) was used in an attempt to differentiate pregnant women with toxoplasma serologic profiles (TSPs) i ndicative of recently acquired infections (acute profile) from those with T SPs indicative of infections acquired in the distant past (chronic profile) . In general, immunoglobulin G antibodies in sera from women with the acute profile reacted more strongly with the recombinant antigens than did those in sera from women with the chronic profile. However, reactivities differe d significantly between antigens that reacted with a single serum and betwe en sera that reacted with a single antigen. Because of these variations, we employed a combination of the four antigens in an ELISA (Comb-ELISA) and e valuated its ability to distinguish pregnant women,vith the acute profile f rom those with the chronic profile. Eighteen of 20 (90%) sera from acute-pr ofile women were positive in the Comb-ELISA, whereas 69 of 70 (98.6%) sera from the chronic-profile women were negative. Thus, the Comb-ELISA may be u seful for diagnosis of toxoplasmosis in pregnant women and for differentiat ion between recently acquired infections and infections acquired in the mor e distant past.