scholarly journals IgG AVIDITY WESTERN BLOT USING Toxoplasma gondii rGRA-7 CLONED FROM NUCLEOTIDES 39-711 FOR SERODIAGNOSIS OF ACUTE TOXOPLASMOSIS

2013 ◽  
Vol 55 (2) ◽  
pp. 79-83 ◽  
Author(s):  
Poonam S. Deshpande ◽  
Dupadahalli Kotresha ◽  
Rahmah Noordin ◽  
Muhammad Hafiznur Yunus ◽  
Geita Saadatnia ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Western Blot ◽  
Chronic Infection ◽  
Acute Infection ◽  
Congenital Infection ◽  
Recombinant Antigen ◽  
Serum Samples ◽  
Serological Profile ◽  
Igg Avidity ◽  
Acute Toxoplasmosis

Toxoplasmosis is an important cause of congenital infection. The present study was performed to evaluate the usefulness of recombinant (r) GRA-7 cloned from nucleotides (n) 39-711 in discriminating between acute and chronic toxoplasmosis. First, commercial IgM, IgG and IgG avidity ELISAs were used to determine the serological profile of the sera. Serum samples were from 20 symptomatic patients with acute infection (low IgG avidity, IgM positive), 10 with chronic infection (high IgG avidity, IgM negative) and 10 with indeterminate IgG avidity (IgM positive) which were tested for IgG avidity status with an in-house developed IgG avidity Western blot using the rGRA-7 recombinant antigen. All 20 sera from cases of probable acute infection showed bands which either faded out completely or reduced significantly in intensity after treatment with 8 M urea, whereas the band intensities of the 10 serum samples from chronic cases remained the same. Of the 10 sera with indeterminate IgG avidity status, after treatment with 8 M urea the band intensities with six sera remained the same, two sera had completely faded bands and another two sera had significantly reduced band intensities. Discrimination between acute and chronic toxoplasmosis was successfully performed by the in-house IgG avidity Western blot.

scholarly journals Toxoplasmosis and pregnancy: Perinatal results and association of the IgG avidity test with congenital infection in pregnant women with positive anti-Toxoplasma gondii IgM [Abstract in English]

2010 ◽  
Vol 20 (1) ◽  
pp. 45
Author(s):  
Virgílio Gonçalves de Souza-Júnior ◽  
Ernesto Antonio Figueiró-Filho ◽  
Danilo De Cerqueira Borges ◽  
Vanessa Marcon Oliveira ◽  
Lílian Rezende Coelho
Keyword(s):  
Toxoplasma Gondii ◽  
Pregnant Women ◽  
Predictive Value ◽  
Congenital Infection ◽  
Neonatal Infection ◽  
High Avidity ◽  
Igg Avidity ◽  
Risk Pregnancy ◽  
Avidity Test ◽  
Acute Toxoplasmosis

AIMS: To verify the perinatal outcomes in pregnant women with acute toxoplasmosis, and to determine if there was association between the results of Toxoplasma gondii-specific IgG avidity test and the presence or absence of fetal/neonatal infection. METHODS: A cross-sectional study included pregnant women with serological diagnosis of acute toxoplasmosis (presenting a positive Toxoplasma gondii-specific IgM test) attended at the outpatient unit for high-risk pregnancy of the Faculty of Medicine, Federal University of Mato Grosso do Sul, Brazil, in the period from November 2002 to November 2007. Test results demonstrating IgG avidity index above 30% were considered high avidity, while values below 30% were considered low avidity. Fetal and/or neonatal infection was defined by positive result for the polymerase chain reaction in amniotic fluid, or by a positive Toxoplasma gondii-specific IgM test in the newborn's serum. RESULTS: Considering all pregnant women referred to the outpatient unit for high-risk pregnancy in the period of study, frequency of pregnant women with positive Toxoplasma gondii-specific IgM was 10.8% (176/1.634). The rate of congenital infection in these patients was 4% (7/176). The IgG avidity test was performed in 162 patients (92% of the 176 pregnant women with positive IgM), and the avidity was high in 144 (88.9%). There was an association (p=0.003) between high avidity and no fetal/neonatal toxoplasmosis in our sample, with a prevalence ratio of 13.4 (confidence interval [CI] 95% 2.2-86.6). The positive predictive value of the avidity test (probability of congenital infection with a low avidity) was 22% (95% 6%-47%), while the negative predictive value (probability of absence of congenital infection with a high avidity) was 98% (95% CI 94% -99%). CONCLUSIONS: In this study the rate of congenital infection in pregnant women diagnosed with acute toxoplasmosis was 4%. In pregnant women with positive Toxoplasma gondii-specific IgM, results of Toxoplasma gondii-specific IgG avidity test were associated with the presence or absence of congenital infection, with a high negative predictive value (no fetal/neonatal infection when avidity was high).

scholarly journals Use of MAG1 Recombinant Antigen for Diagnosis of Toxoplasma gondii Infection in Humans

2007 ◽  
Vol 14 (3) ◽  
pp. 220-225 ◽  
Author(s):  
Lucyna Holec ◽  
Elżbieta Hiszczyńska-Sawicka ◽  
Artur Gąsior ◽  
Anna Brillowska-Dąbrowska ◽  
Józef Kur
Keyword(s):  
Toxoplasma Gondii ◽  
Diagnostic Tests ◽  
Expression System ◽  
Recombinant Antigen ◽  
Acute Stage ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Acute Toxoplasmosis ◽  
Toxoplasma Gondii Infection ◽  
Potential Use

ABSTRACT This paper describes the cloning, purification, and serological applications of matrix antigen MAG1 of Toxoplasma gondii. The expression system used allows the production of a large amount of T. gondii recombinant protein, which was assessed for its potential use in an enzyme-linked immunosorbent assay (ELISA) for detection of T. gondii infection in humans. Serum samples from 117 patients with different stages of infection, along with 10 serum samples from seronegative patients obtained for routine diagnostic tests, were used. The results were compared with those of an ELISA that uses a native T. gondii antigen extract. The MAG1 antigen detected antibodies more frequently from the acute stage (97.3%) than from the chronic stage (7.5%) of toxoplasmosis. Hence, this antigen may be used as a tool for detection of T. gondii immunoglobulin G antibodies in persons with acute toxoplasmosis.

Identification of Biomarkers for Diagnosis and Prognosis of Congenital and Acute Toxoplasmosis

2020 ◽  
Author(s):  
Heloisa Ribeiro Storchilo ◽  
Giulianne Monteiro Teixeira ◽  
André Luís Elias Moreira ◽  
Taynara Cristina Gomes ◽  
Clayton Luiz Borges ◽  
...  
Keyword(s):  
Acute Infection ◽  
Congenital Toxoplasmosis ◽  
Congenital Infection ◽  
Igg Antibodies ◽  
Childbearing Age ◽  
Serum Samples ◽  
Infection Group ◽  
Serological Tests ◽  
Diagnosis And Prognosis ◽  
Acute Toxoplasmosis

Abstract Background The diagnosis of congenital toxoplasmosis can be inconclusive in many cases. Despite the several serological tests developed, the literature on biomarkers that can assist in the diagnosis of congenital an acute toxoplasmosis is limited. The objective of this study was to analyze the immunoreactive profile of Toxoplasma gondii protein bands with the potential to be biomarkers for diagnosis and prognosis of congenital and acute toxoplasmosis. Methods Peripheral blood samples from women of childbearing age and/or pregnant women diagnosed with acquired toxoplasmosis as well as from congenitally infected children were selected and submitted to immunoblotting for analysis of the immunoreactive bands profile by immunoglobulin G (IgG) antibodies. Results When comparing the immunoreactive bands profile for antibodies present in samples from different groups and subgroups, the 150, 18.5, and 16.96-kDa bands were more immunoreactive with the antibodies present in serum samples from the acquired infection group. The 343, 189, 150, 75, and 42-kDa bands showed more chance to be detected by the symptomatic congenital infection subgroup samples, while the 61, 50, and 16.96-kDa bands were significantly immunoreactive with the acute infection subgroup samples. Conclusions The identification of these potential biomarkers can assist in early diagnosis and treatment of congenital toxoplasmosis.

Evaluation of detection of Toxoplasma gondii DNA in animal blood samples by quantitative PCR

2012 ◽  
Vol 7 (3) ◽  
pp. 431-435
Author(s):  
Lenka Luptakova ◽  
Alexandra Valencakova ◽  
Pavol Balent ◽  
Beata Malcekova ◽  
Eva Petrovova
Keyword(s):  
Toxoplasma Gondii ◽  
Real Time ◽  
Real Time Pcr ◽  
Chronic Infection ◽  
Acute Infection ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Blood Samples ◽  
Group Iii ◽  
Group I

AbstractAim of the study: The purpose of this study was to find out the relationship between the phase of infection (acute or persistent) and the ability of quantitative PCR to detect DNA of Toxoplasma gondii in circulating leukocytes in blood. Methodology: Animal serum samples were examined (50 sheep, 47 dogs, 32 dairy cows, 91 wild boars and 36 rabbits) for the occurrence of IgM and IgG antibodies to T. gondii by ELISA. Uncoagulated blood samples from the same animals were examined for the detection of T. gondii DNA in circulating leukocytes by real-time PCR. Results: Only IgM antibodies, characteristic for acute infection, were detected in 45 of the 256 serum samples (17.6%). Only IgG antibodies, corresponding with chronic infection, were detected in 120 of the 256 samples (46.8%). In 91 of the 256 samples (35.5%) neither IgM or IgG were detected by ELISA. For real-time PCR, animals were divided into three groups based on the serological results: (group I — acute infection, group II — chronic infection, and group III — no infection). In group I, the presence of T. gondii DNA was detected in 9 out of 45 samples (20%), whereas in group II only 1 of 120 samples was positive for T. gondii DNA (0.8%). In group III, no DNA of T. gondii (0/91 samples) was detected by real-time PCR. Significance: The proof of DNA by real-time PCR in IgM positive samples was statistically significant in comparison to IgG positive samples (P<0.0001).

scholarly journals Use of Avidity Enzyme-Linked Immunosorbent Assay and Avidity Western Blot to Discriminate between Acute and Chronic Neospora Caninum Infection in Cattle

2005 ◽  
Vol 17 (5) ◽  
pp. 442-450 ◽  
Author(s):  
A. Aguado-Martínez ◽  
G. Álvarez-García ◽  
I. Arnaiz-Seco ◽  
E. Innes ◽  
L. M. Ortega-Mora
Keyword(s):  
Western Blot ◽  
Chronic Infection ◽  
Primary Infection ◽  
Neospora Caninum ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Infected Cattle ◽  
Serum Samples ◽  
Caninum Infection ◽  
Igg Avidity

Avidity serological tests (avidity enzyme-linked immunosorbent assay [ELISA] and avidity Western blot) were developed and used to differentiate between acute (primary infection, reinfection, and recrudescence) and chronic Neospora caninum infection in cattle. In addition, the pattern of immunoglobulin G (IgG) avidity maturation against different specific antigens of N. caninum tachyzoites was studied. Sequential serum samples were collected from cattle naturally and experimentally infected with N. caninum. Four groups of experimentally infected cattle were included in the study and were representative of primary infection, reinfection, chronic infection, and noninfection. Serum samples were also collected from naturally infected cattle classified into nonaborting and aborting cows on the basis of clinical findings and serological profiles, and a third group composed of seronegative cows that seroconverted during the course of the experiment. All samples were tested by avidity ELISA and avidity Western blot. The IgG avidity ELISA allowed the discrimination between primary and chronic infection because all experimentally primary-infection cows showed low avidity indexes at week 4 postinfection (p.i.) compared with the high avidity values found at week 20 postinfection. However, this test did not allow the discrimination of reinfection or recrudescence from chronic infection. Regarding IgG avidity Western blot results, no antigenic markers correlating with acute (primary infection, recrudescence, and reinfection) or chronic infection were recognized. However, the 17-kD immunodominant antigen was mostly responsible for high avidity values obtained by avidity ELISA because it was intensively recognized by high-avidity antibodies in all chronically infected animals after urea treatment.

scholarly journals A Transmembrane Domain-Containing Surface Protein from Toxoplasma gondii Augments Replication in Activated Immune Cells and Establishment of a Chronic Infection

2009 ◽  
Vol 77 (9) ◽  
pp. 3731-3739 ◽  
Author(s):  
Angela M. Pollard ◽  
Sini Skariah ◽  
Dana G. Mordue ◽  
Laura J. Knoll
Keyword(s):  
Nitric Oxide ◽  
Toxoplasma Gondii ◽  
Immune Cells ◽  
Chronic Infection ◽  
Transmembrane Domain ◽  
Acute Infection ◽  
Surface Protein ◽  
Activated Macrophages ◽  
Serum Samples ◽  
Parasite Replication

ABSTRACT Toxoplasma gondii mutants identified as defective in the establishment of chronic infection were screened to isolate those specifically impaired in their ability to replicate within activated macrophages. One of the identified mutants contains an insertion in the hypothetical gene TGME49_111670. Genetic complementation restores the ability of the mutant to replicate in immune cells and produce cysts in the brains of mice. While the mutant is more sensitive to nitric oxide than is its parental strain, it is not defective in its ability to suppress nitric oxide. The disrupted protein has no significant homology to proteins with known functions, but is predicted to have one transmembrane domain. Immunofluorescence shows the protein on the parasite surface, even in activated macrophages, colocalizing with a tachyzoite surface antigen, SAG1, and oriented with its C-terminal end external. Western analysis reveals that the protein is downregulated in bradyzoites. Despite the tachyzoite specificity of this protein, mice infected with the mutant succumb to acute infection similarly to those infected with the parent strain. Serum samples from mice with chronic T. gondii infection react to a polypeptide from TGME49_11670, indicating that the protein is seen by the immune system during infection. This study is the first to characterize a T. gondii surface protein that contains a transmembrane domain and show that the protein contributes to parasite replication in activated immune cells and the establishment of chronic infection.

scholarly journals Toxoplasma gondii: Usefulness of ROP 1 Recombinant Antigen in an Immunoglobulin G Avidity Assay for Diagnosis of Acute Toxoplasmosis in Humans

2010 ◽  
Vol 59 (4) ◽  
pp. 307-310 ◽  
Author(s):  
LUCYNA HOLEC-GĄSIOR ◽  
DOROTA DRAPAŁA ◽  
DARIUSZ LAUTENBACH ◽  
JÓZEF KUR
Keyword(s):  
Toxoplasma Gondii ◽  
Immunoglobulin G ◽  
Chronic Infection ◽  
Recombinant Antigen ◽  
Acute Stage ◽  
High Avidity ◽  
Specific Antibodies ◽  
Avidity Assay ◽  
Avidity Test ◽  
Acute Toxoplasmosis

The results present in this study suggest that the Toxoplasma gondii recombinant ROP1 antigen in an IgG avidity test can be useful for detection of acute stage of infection. Specific antibodies of low avidity were detected in most of the sera from individuals with acute toxoplasmosis, while the absence or specific antibodies of high avidity were detected in sera from patients with chronic infection.

scholarly journals Use of Dense Granule Antigen GRA6 in an Immunoglobulin G Avidity Test To Exclude Acute Toxoplasma gondii Infection during Pregnancy

2010 ◽  
Vol 17 (9) ◽  
pp. 1349-1355 ◽  
Author(s):  
Hossein Elyasi ◽  
Jalal Babaie ◽  
Hélène Fricker-Hidalgo ◽  
Marie-Pierre Brenier-Pinchart ◽  
Mehrak Zare ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Immunoglobulin G ◽  
Chronic Infection ◽  
Dense Granule ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Recent Infection ◽  
Igg Avidity

ABSTRACT The usefulness of a specific immunoglobulin G (IgG) avidity enzyme-linked immunosorbent assay (ELISA) based on recombinant GRA6 antigen for distinguishing between acute and chronic Toxoplasma infection was investigated. Two sets of serum samples obtained from pregnant women with acute, chronic, or no Toxoplasma infection collected in France and Iran were used. Among the French subjects, 19 of 20 (95%) women who experienced seroconversion during the past 4 months before sampling displayed low-avidity IgG antibodies against GRA6, while all 17 (100%) women with chronic infection had high-avidity antibodies. When the Euroimmun IgG avidity ELISA was used, 15 of 19 (78.9%) recently infected women had low-avidity antibodies, and 20 of 22 (90.9%) women with chronic infection displayed high-avidity antibodies. The results suggested better performance of the GRA6 avidity ELISA than the Euroimmun avidity ELISA for exclusion of a recent infection occurring less than 4 months previously. Similarly, all 35 Iranian women with acute Toxoplasma infection had low-avidity antibodies against GRA6, whereas all 34 women with chronic infection displayed IgG antibodies of high avidity, indicating the value of GRA6 avidity testing for ruling out a recent infection. Avidity tests based on lysed whole-cell Toxoplasma gondii antigen are currently used to exclude recently acquired infections; however, the use of recombinant antigen(s) might improve the diagnostic performance of avidity tests and facilitate the development of more standardized assays.

scholarly journals Evaluation of the New Elecsys Toxo IgG Avidity Assay for Toxoplasmosis and New Insights into the Interpretation of Avidity Results

2012 ◽  
Vol 19 (11) ◽  
pp. 1838-1843 ◽  
Author(s):  
Jean-Benjamin Murat ◽  
Coralie L'Ollivier ◽  
Hélène Fricker Hidalgo ◽  
Jacqueline Franck ◽  
Hervé Pelloux ◽  
...  
Keyword(s):  
Severe Disease ◽  
High Avidity ◽  
Serum Samples ◽  
Recent Infection ◽  
Content Type ◽  
Additional Information ◽  
Avidity Assay ◽  
Igg Avidity ◽  
Acute Toxoplasmosis ◽  
Almost All

ABSTRACTDetection and treatment of acute toxoplasmosis during pregnancy can avoid severe disease of the fetus. In this context, assessment of anti-ToxoplasmaIgG avidity has been shown to exclude recent infection. The Elecsys Toxo IgG and IgM assays (Roche Diagnostics) have been validated for screening pregnant women and a new assay, Elecsys Toxo IgG Avidity, was recently developed. Our aims were to investigate the performance characteristics of this new avidity assay and explore whether additional information can be provided by avidity assays. The Elecsys assay was compared with the Vidas (bioMérieux) and Architect (Abbott) Avidity assays using two sets of serum samples (n= 291 andn= 255). The rate of general agreement between the Elecsys and Vidas assays was 74%, and that between the Elecsys and Architect assays was 83%. For 11% of the serum samples, avidity was high with the Vidas assay and within the gray zone with the Elecsys assay. None of the assays detected high-avidity antibodies in serum taken <4 months after infection. Avidity values of >90% were exclusively reported in sera taken >9 months after infection by the Elecsys and Architect assays. Almost all avidities of <19% with the Elecsys assay and <17% with the Architect assay corresponded to sera taken <3 and <2 months after infection, respectively. The Elecsys IgG Avidity assay can be used to exclude recent infection. New ways of interpreting the avidity result are also suggested: very high or low values could exclude infections within the last 9 months or help to confirm a recent infection, respectively. However, these potential interpretations require further investigation.

scholarly journals Anti-Toxoplasma gondii IgG avidity testing is necessary for diagnosis of acute toxoplasmosis

2017 ◽  
Vol 12 (1) ◽  
pp. 87-88
Author(s):  
Idris-Abdullahi Nasir ◽  
Muhammad S. Shehu ◽  
Hafiz A. Adekola
Keyword(s):  
Toxoplasma Gondii ◽  
Igg Avidity ◽  
Acute Toxoplasmosis
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