title: Kinetic analysis of the humoral immune response against 3 Toxoplasma gondii-recombinant proteins in infants with suspected congenital toxoplasmosis.
abstract: The reactivity values of Toxoplasma gondii ROP2, GRA4, and GRA7 recombinant antigens (rAgs) were analyzed by immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) in 23 congenitally infected (I) and 36 noninfected (NI) infants. The reactivity values observed from the serum samples of I versus NI infants for each recombinant protein were 91% versus 67% for rROP2 (P = .05), 86% versus 29% for rGRA4 (P < .001), and 56% versus 11% for rGRA7 (P = .003). The follow-up showed that serum samples from NI infants became negative for specific IgG at 5.8 months (95% confidence interval [CI], 4.9-6.7) using a commercial assay; meanwhile, by specific recombinant protein ELISA, the samples became negative at 3.7 months with rROP2 (95% CI, 2.8-4.6), at 1.3 months with rGRA4 (95% CI, 0.8-1.8), and at 0.9 months with rGRA7 (95% CI, 0.5-1.3). Kinetic analysis also showed that serum samples from group I presented different IgG-profiles among rAgs. The rROP2 IgG profile was similar to that of the commercial assay, whereas rGRA4 and rGRA7 profiles showed a gradual decrease along the period of the study. The potential of the utility of rAgs to develop a diagnostic system that discriminates congenitally I infants from NI is discussed.
authors.affiliation: Parasitología, Hospital de Niños Ricardo Gutierrez, Buenos Aires 1429, Argentina.
authors.forename: Jaime
authors.initials: J
authors.lastname: Altcheh
authors.forename: Natalia S
authors.initials: NS
authors.lastname: Diaz
authors.forename: Carolina M
authors.initials: CM
authors.lastname: Pepe
authors.forename: Valentina
authors.initials: V
authors.lastname: Martin
authors.forename: Monica
authors.initials: M
authors.lastname: Nigro
authors.forename: Hector
authors.initials: H
authors.lastname: Freilij
authors.forename: Sergio O
authors.initials: SO
authors.lastname: Angel
mesh_terms: D000375:Aging; D000818:Animals; D000917:Antibody Formation; D000953:Antigens, Protozoan / Q000276:immunology; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D005786:Gene Expression Regulation; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D007700:Kinetics; D002955:Leucovorin / Q000627:therapeutic use; D011739:Pyrimethamine / Q000627:therapeutic use; D011994:Recombinant Proteins / Q000276:immunology*; D012680:Sensitivity and Specificity; D013411:Sulfadiazine / Q000627:therapeutic use; D014122:Toxoplasma / Q000276:immunology*; D014125:Toxoplasmosis, Congenital / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology*
chemical_list: D000953:Antigens, Protozoan; D000981:Antiprotozoal Agents; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D013411:Sulfadiazine; D002955:Leucovorin; D011739:Pyrimethamine