Study of efficient diagnostic of T. gondii antigens - GRA-1, GRA-7 and SAG-1 associated as multiple peptide antigen (MAPs) in the diagnostic of adquired toxoplasmosis

• Grant number: 05/03830-8
• Support Opportunities: Regular Research Grants
• Duration: May 01, 2006 - October 31, 2008
• Field of knowledge: Biological Sciences - Immunology - Applied Immunology
• Principal Investigator: Antonio Walter Ferreira
• Grantee: Antonio Walter Ferreira
• Host Institution: Instituto de Medicina Tropical de São Paulo (IMT). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The discrimination between active and past infection is especially important in illnesses like toxoplasmose, where the infection is common in the population, being able to lead to the development of important patologias in immunocomprimised, pregnant women and newborn. Serological methods tradicional as immunofluorescence and hemagglutination, present limits in that it says respect to the discrimination of the phases of the illness and despite the variety of tests automatized currently available, a positive serological in isolated sample, without a demonstration of seroconversion, represents a problem for the medical, a time that the detention of residual IgM if has shown frequent with the use of methods of the great sensitivity. Exactly with the association of the avidity test for IgG in the briefing of these cases, primary infections with negative results for IgM and IgG antibodies of low avidity persist, as well as, primary infections with positive IgM and IgG antibodies with avidity high, that can be indicative of old infection. Recent advances have been made in the use of excreted-secreted antigens (ESA) for the taquizoítas forms of T. gondii in the diagnosis of toxoplasmose. Recently, in our laboratory, we evaluate the avidez of the IgG antibodies anti-SAG-1 of the ESA for imunoblot, as marking of recent acute toxoplasmosis, getting resulted promising. To leave of these results, we will associate the protein fractions of ESA - GRA-1 and GRA-7, important targets of the immune in patients with recent acute toxoplasmosis the SAG-1 in the form of MAPs (multiple peptide antigens), for the detention of antibodies IgG, IgM and IgA in intention to get a test that presents one better comparative disgnostic efficiency to the tests currently used in the diagnosis of human toxoplasmosis. (AU)