High diagnostic efficiency of IgM-ELISA with the use of multiple antigen peptides (MAP1) from T. gondii ESA (SAG-1, GRA-1 and GRA-7), in acute toxoplasmosis

Abstract

SUMMARYThe main serological marker for the diagnosis of recent toxoplasmosis is the specific IgM antibody, along with IgG antibodies of low avidity. However, in some patients these antibodies may persist long after the acute/recent phase, contributing to misdiagnosis in suspected cases of toxoplasmosis. In the present study, the diagnostic efficiency of ELISA was evaluated, with the use of peptides derived from T. gondii ESA antigens, named SAG-1, GRA-1 and GRA-7. In the assay referred to, we studied each of these peptides individually, as well as in four different combinations, as Multiple Antigen Peptides (MAP), aiming to establish a reliable profile for the acute/recent toxoplasmosis with only one patient serum sample. The diagnostic performance of the assay using MAP1, with the combination of SAG-1, GRA-1 and GRA-7 peptides, demonstrated better discrimination of the acute/recent phase from non acute/ recent phase of toxoplasmosis. Our results show that IgM antibodies to MAP1 may be useful as a serological marker, enhancing the diagnostic efficiency of the assay for acute/recent phase of toxoplasmosis.

Seroprevalence of toxoplasmosis, toxocariasis and cysticercosis in a rural settlement, São Paulo State, Brazil

“…Low socioeconomic status is an additional factor contributing to T. gondii infection in Brazilian communities and worldwide. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]27 There was also a significant increase in infections in females compared to males. This may be a result of women remaining near or inside the house, close to domestic animals, and becoming predisposed to T. gondii infection.…”

“…14,16 Toxoplasma gondii IgG and IgM Toxoplasma gondii IgG and IgM antibodies were detected using ELISA containing T. gondii excretorysecretory antigen (ESA) peptides. 11,20 The ESA peptides chosen were granule protein 1 (GRA-1), which correlates with chronic toxoplasmosis, granule protein 7 (GRA-7) which is detected in acute toxoplasmosis, 21,22 and surface antigen 1 (SAG-1), which is present only in the tachyzoite stage and is a marker of acute toxoplasmosis, 23 based on the methodology described by Araú jo and Ferreira. 11,20…”

“…[6][7][8] The diagnosis of toxocariasis, toxoplasmosis, and cysticercosis are based on clinical examination, diagnostic images, and serology. [9][10][11] For the serodiagnosis of toxocariasis, an enzyme-linked immunosorbent assay (ELISA) using T. canis larvae excretorysecretory antigens (TES) is widely used to detect specific IgG antibodies. 9 For acute toxoplasmosis, the serodiagnosis is made by detecting specific IgM antibodies and IgG through an avidity test.…”

“…9 For acute toxoplasmosis, the serodiagnosis is made by detecting specific IgM antibodies and IgG through an avidity test. 11 The assay of choice for serodiagnosis of cysticercosis in humans is the immunoblot assay using the lentil lectin chromatographically purified (CP) glycoproteins antigens derived from T. solium metacetodes. 12 However, other working groups have found that antigens from other species may be useful for diagnosing cysticercosis, such as 14 and 18 kDa purified antigens from Taenia crassiceps.…”

“…However, for all of these agents, false-negative and false-positive ELISA results have been observed. [9][10][11] Invasion and formation of a settlement beside the area to be occupied is one of the first steps used by landless worker movements in Brazil to pressurize the local authorities against expropriation, distribution, and settlement arrangements. Dozens of new settlements have been formed in the past decades in the Pontal of Paranapanema region, and there are disputes over land between landless workers and cattle farmers.…”