Kinetic analysis of the humoral immune response against 3 Toxoplasma gondii-recombinant proteins in infants with suspected congenital toxoplasmosis

Diagn Microbiol Infect Dis. 2006 Oct;56(2):161-5. doi: 10.1016/j.diagmicrobio.2006.03.012. Epub 2006 May 19.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging
  • Animals
  • Antibody Formation*
  • Antigens, Protozoan / immunology
  • Antiprotozoal Agents / therapeutic use
  • Gene Expression Regulation
  • Humans
  • Immunoglobulin G / immunology
  • Infant
  • Infant, Newborn
  • Kinetics
  • Leucovorin / therapeutic use
  • Pyrimethamine / therapeutic use
  • Recombinant Proteins / immunology*
  • Sensitivity and Specificity
  • Sulfadiazine / therapeutic use
  • Toxoplasma / immunology*
  • Toxoplasmosis, Congenital / diagnosis*
  • Toxoplasmosis, Congenital / drug therapy
  • Toxoplasmosis, Congenital / immunology*

Substances

  • Antigens, Protozoan
  • Antiprotozoal Agents
  • Immunoglobulin G
  • Recombinant Proteins
  • Sulfadiazine
  • Leucovorin
  • Pyrimethamine