P35 and P22 Toxoplasma gondii antigens abbreviate regions to diagnose acquired toxoplasmosis during pregnancy: towards single-sample assays

COSTA, JUAN G; PERETTI, LEANDRO E; GARCÍA, VALERIA; PEVERENGO, LUZ; GONZALEZ, VERÓNICA DG.; GUGLIOTTA, LUIS M.; LAGIER, CLAUDIA M.; MARCIPAR, IVÁN S.

CLINICAL CHEMISTRY AND LABORATORY MEDICINE

WALTER DE GRUYTER & CO

Lugar: Berlin; Año: 2016 vol. 55

1434-6621

P35 and P22 Toxoplasma gondii proteinsare recognized by specific IgG at the early infection stage, making them idealfor acute-toxoplasmosis pregnancy control. Both proteins have been studied todiscriminate between acute and chronic toxoplasmosis. However, results were hardlycomparable because different protein obtainment procedures led to differentantigens, the reference panels used were not optimally typified, and aviditytests were either not performed or narrowly examined. We bioinformaticallypredicted P35 and P22 regions with the highest density of epitopes, andexpressed them in pET32/BL21DE3 alternative expression system, obtaining thesoluble proteins rP35a and rP22a. We assessed their diagnostic performanceusing pregnant woman serum samples typified as: not infected, NI (IgG-, IgM-),typical-chronic, TC (IgM-, IgG+), presumably-acute, A (IgM+, low-avidity IgG),and recently-chronic, RC (IgM+, high-avidity IgG). rP35a performed better thanrP22a to differentiate A from RC, the areas under curve (AUC) being 0.911 and0.818, respectively. They however performed similarly to differentiate A fromTC+RC (AUC: 0.915 and 0.907, respectively). rP35a and rP22a evaluation byavidity ELISA to discriminate A from RC rendered AUC values of 0.974 and 0.921,respectively. The indirect ELISA and avidity ELISA results analyzed in tandemwere consistent with those obtained using commercial kits. rP35a and rP22afeatures suggest that, by using them complementary, they could replace parasitelysate for toxoplasmosis infection screening, and for acute toxoplasmosisdiagnosis. Our proposal should be validated by a longitudinal study and maylead to a reliable toxoplasmosis pregnancy control, performing tests in onlyone serum sample.