Avidez de anticorpos IgG específicos como marcadores de infecção primária recente pelo Toxoplasma gondii

Camargo, M. E.; Silva, Sueli M. da; Leser, Paulo Guilherme; Granato, Celso H.

doi:10.1590/s0036-46651991000300008

Cited by 39 publications

(31 citation statements)

References 3 publications

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“…Determination of the low avidity of immunoglobulin G antibodies to T. gondii is a very useful tool for evaluating acute infection, reflecting the degree of maturation of these molecules during the immune response (6). Our results clearly demonstrate that congenital transmission only occurs when the antibodies present have low avidity, and these findings were correlated with the acute phase of infection, when the parasites inside the giant trophoblasts were unstained by PAS, characterizing the presence of tachyzoites (12).…”

Section: Discussionmentioning

confidence: 62%

Effect ofToxoplasma gondiiInfection Kinetics on Trophoblast Cell Population inCalomys callosus, a Model of Congenital Toxoplasmosis

et al. 2002

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This work evaluated the kinetics of events that occur in the placenta of Calomys callosus after Toxoplasma gondii infection. Animals on the first day of pregnancy (dop) and virgin nonpregnant females were perorally infected with 20 cysts of T. gondii strain ME49. After 100 days of infection, the virgin animals were mated and received an additional 20 cysts on the first dop. The placentas and the embryos from both acutely and chronically infected animals were analyzed up to day 20 of pregnancy by morphological and immunocytochemical assays. Noninfected and infected animals exhibited placenta with normal morphology. From the seventh dop and infection onwards, liver and spleen cells of the infected animals contained several parasitophorous vacuoles. On the 13th day, the maternal blood present at the placental blood spaces contained T. gondii-infected leukocytes. Infected placental cells were only seen on the 15th dop, being the trophoblast giant cells, the first cell type to contain signs of the parasite internalization, followed by labyrinth zone cells 24 h later and spongiotrophoblast cells only after the 19th dop. Fetal liver and brain were infected by T. gondii concomitantly to the labyrinth cell infection. No signals of infection were observed on placentas and embryos from chronically infected animals. Therefore, considering the sequence of events leading to the infection of the various organs, it could be hypothesized that the placenta is infected later on during pregnancy, which may be related to the defense roles played by this structure. However, trophoblast giant cells are unable to completely stop the progression of T. gondii infection towards the fetal tissues. C. callosus was demonstrated to be a suitable experimental model to study the dynamics of congenital toxoplasmosis.

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Section: Discussionmentioning

confidence: 62%

Effect ofToxoplasma gondiiInfection Kinetics on Trophoblast Cell Population inCalomys callosus, a Model of Congenital Toxoplasmosis

et al. 2002

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“…The IgG avidity determination is an important serological marker that can be used to distinguish between acute/recent and non-acute phase, from a single serum sample. However, low IgG avidity results may persist for as long as one year after the primary infection because of immunosuppressive conditions or anti-toxoplasma pharmacotherapy that may affect the kinetics of the IgG avidity maturation 5,11,13,20,23 . The PCR has been successfully used in immunocompromised patients, ocular toxoplasmosis and congenital toxoplasmosis.…”

Section: Discussionmentioning

confidence: 99%

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

Araújo

Ferreira

2010

Rev. Inst. Med. trop. S. Paulo

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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.

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“…High avidity or chaotrope-resistant antibodies are characteristic of memory immune response and chronic infection, and the prevalence of low avidity or chaotrope-sensitive antibodies could indicate acute or recent infection. Urea is the common chaotrope used (CAMARGO et al, 1991), an alternative to ammonium thiocyanate (FERREIRA & KATZIN, 1995). Several studies have reported that the avidity of antibody IgG is a good index of the time of the infection, defining if the acute infection has occurred in the past few months despite conflicting results between tests (BARBERI et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Serology using rROP2 antigen in the diagnostic of toxoplasmosis in pregnant women

Macre¹,

Pires²,

Meireles³

et al. 2009

Rev. Inst. Med. trop. S. Paulo

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SUMMARYToxoplasma gondii causes severe fetal disease during acute infection in pregnant women, thus demanding early diagnosis for effective treatment and fetus preservation. Fetal tests are inefficient and risky, and diagnosis is based on maternal IgM serology, which had weak screening ability due to increased sensitivity, with alternative IgG avidity tests. Here, we performed ELISA and avidity assays using a recombinant T. gondii antigen, rROP2, in samples from 160 pregnant women screened from a large public hospital who were referred due to positive IgM assays. IgG serology and avidity assays were compared using whole T. gondii extract or rROP2. ELISA IgG detection with rROP2 showed good agreement with assays performed with T. gondii extract, but rROP2 IgG avidity assays were unrelated to whole extract antigen IgG avidity, regardless of the chaotrope used. These data show that avidity maturation is specific to individual antigen prevalence and immune response during infection. ELISA rROP2 IgG assays may be an alternative serological test for the diagnosis of toxoplasmosis during pregnancy, although our data do not support their use in avidity assays.

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Avidez de anticorpos IgG específicos como marcadores de infecção primária recente pelo Toxoplasma gondii

Cited by 39 publications

References 3 publications

Effect ofToxoplasma gondiiInfection Kinetics on Trophoblast Cell Population inCalomys callosus, a Model of Congenital Toxoplasmosis

Effect ofToxoplasma gondiiInfection Kinetics on Trophoblast Cell Population inCalomys callosus, a Model of Congenital Toxoplasmosis

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

Serology using rROP2 antigen in the diagnostic of toxoplasmosis in pregnant women

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