A Combination of Antigenic Regions of<i>Toxoplasma gondii</i>Microneme Proteins Induces Protective Immunity against Oral Infection with Parasite Cysts

Beghetto, Elisa; Nielsen, Henrik Vedel; Porto, Paola Del; Buffolano, Wilma; Guglietta, Silvia; Felici, Franco; Petersen, Eskild; Gargano, Nicola

doi:10.1086/427660

Cited by 85 publications

(49 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Seven antigenic regions of the T. gondii polypeptides MIC2a, MIC2b, MIC3, MIC4, M2AP, AMA1, and SAG1, which had been shown previously to contain B-cell epitopes (3,5), were expressed as fusion products with the bacterial protein GST. Immunoreactivity of GST fusion proteins with IgG antibodies in sera from infected and uninfected infants was determined.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Use of Recombinant Antigens for Early Postnatal Diagnosis of Congenital Toxoplasmosis

Buffolano

Beghetto²,

Pezzo

et al. 2005

J Clin Microbiol

Self Cite

View full text Add to dashboard Cite

The main objective of this work was to improve the early serologic diagnosis of toxoplasmosis in children at risk of congenital infection by using recombinant antigens. Serum samples from 104 infants born to mothers with primary Toxoplasma gondii infection acquired during pregnancy, of which 35 were congenitally infected and 22 had clinical silent toxoplasmosis at birth, were included. Immunoglobulin M (IgM), IgG, and IgG subtype antibodies against epitopes carried by fragments of T. gondii MIC2, MIC3, MIC4, M2AP, AMA1, and SAG1 gene products were measured by performing parallel enzyme immunoassays (Rec-ELISAs). Recombinant antigens preferentially reacted with IgG antibodies from infected infants compared to uninfected subjects (P < 0.0001), indicating that sera from infected children recognized a more diverse repertoire of antigens than sera transferred over the placenta from the mothers. Using two serial samples collected within 3 months of life, it was possible to demonstrate a neosynthesis of specific anti-MIC2 and anti-SAG1 immunoglobulin G, mainly of the IgG2 subtype, in 13 out of 20 infants with congenital toxoplasmosis. IgM antibodies in 97% of infected infants reacted with at least one of the recombinant antigens, confirming the diagnosis of congenital infection as soon as 2 months after birth (P < 0.0001). The use of recombinant antigens is effective in distinguishing T. gondii-infected from uninfected infants and shows that assays based on recombinant antigens improve the diagnosis of newborns with congenital toxoplasmosis.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Immunodominant regions of T. gondii proteins have previously been identified (2)(3)(4)(5)9). The immunoreactivity of seven distinct fragments of T. gondii, the MIC2, MIC3, MIC4, M2AP, AMA1, and SAG1 proteins, expressed as GST fusion products, was assessed with sera from infants with congenital T. gondii infection.…”

Section: Discussionmentioning

confidence: 99%

Use of Recombinant Antigens for Early Postnatal Diagnosis of Congenital Toxoplasmosis

Buffolano

Beghetto²,

Pezzo

et al. 2005

J Clin Microbiol

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recombinant proteins produced in Escherichia coli as fusion proteins with glutathione S-transferase (GST) were purified from the cytoplasm of bacterial cells by affinity chromatography, as described previously (3,5). Briefly, recombinant E. coli was induced with isopropyl-␤-D-thiogalactopyranoside, centrifuged, and suspended in STE buffer (10 mM Tris-HCl [pH 8], 150 mM NaCl) containing 100 g/ml of lysozyme and protease inhibitor cocktail (Boehringer, Mannheim, Germany).…”

Section: Methodsmentioning

confidence: 99%

Chimeric Antigens ofToxoplasma gondii: Toward Standardization of Toxoplasmosis Serodiagnosis Using Recombinant Products

Beghetto¹,

Spadoni²,

Bruno³

et al. 2006

J Clin Microbiol

Self Cite

View full text Add to dashboard Cite

We have evaluated the diagnostic utility of six antigenic regions of the Toxoplasma gondii MIC2, MIC3, M2AP, GRA3, GRA7, and SAG1 gene products, assembled in recombinant chimeric antigens by genetic engineering, in order to replace the soluble, whole-cell tachyzoite extract in serological assays. Serum samples from 100 adults with acquired T. gondii infection and from 30 infants born to mothers with primary toxoplasmosis contracted during pregnancy, of whom 20 were congenitally infected, were included. Immunoglobulin G (IgG) and IgM antibodies against epitopes carried by chimeric antigens were measured by performing parallel enzyme immunoassays (recombinant enzyme-linked immunosorbent assays [Rec-ELISAs]), and the results obtained by standard commercial assays with the whole-cell Toxoplasma antigen and assays with the chimeric antigens were compared. Our results demonstrate that IgG and IgM Rec-ELISAs with individual chimeric antigens have performance characteristics comparable to those of the corresponding commercial assays. Furthermore, we show that IgM-capture assays based on chimeric antigens improve the ability to diagnose congenital toxoplasmosis postnatally compared with the ability to diagnose congenital toxoplasmosis by the use of standard assays. The use of recombinant chimeric antigens is effective in distinguishing T. gondii-infected individuals from T. gondii-uninfected individuals and shows that immunoassays based on recombinant products could provide the basis for standardized commercial tests for the serodiagnosis of toxoplasmosis.Human infection by Toxoplasma gondii is generally asymptomatic and induces a self-limiting disease. In contrast, primary T. gondii infection acquired during gestation can be transmitted to the fetus through the placenta and may cause miscarriage, permanent neurological damage, premature birth, and visual impairment (15,29,32). Toxoplasmosis during gestation represents a formidable task for the clinician due to its subclinical course in the majority of pregnant women and the unpredictable long-term outcome of congenital infection (11,16,32). To implement suitable therapies in good time and to avoid neonatal malformations or reduced eyesight in newborns, it is essential to establish when the primary infection has been acquired in the mother and to determine if vertical transmission to the fetus has occurred.The diagnosis of T. gondii infection can be established by detecting parasite-specific DNA sequences in body fluids and tissues or Toxoplasma-specific immunoglobulins in sera from infected individuals (2,20,30). Serological methods are generally preferred, since the sensitivities and the specificities of other methods can be affected by the appropriateness of sample handling and shipping and storage conditions. Furthermore, parasitemia may be of short duration, further limiting the value of detection of DNA in amniotic fluid and peripheral blood.The diagnosis of toxoplasmosis by serological methods routinely uses immunoenzymatic assays to detect the presence of the var...

show abstract

“…A study combining the two bradyzoite antigens BAG1 and MAG1 in a cocktail DNA vaccine also found a significant reduction in the number of brain cysts (62%), but no sterile immunity (Nielsen et al 2006). A similar study, using a combination of antigens delivered as plasmids coding for regions of microneme proteins including MIC2, MIC3, MIC4, M2AP and AMA1, resulted in a significant reduction (84%) of the number of cysts, but not sterile immunity (Beghetto et al 2005). Recently, a GRA7 DNA vaccine was found to be correlated with high-level protection against brain cyst formation and a cocktail DNA vaccine with a combination of GRA1 and GRA7 could reduce the T. gondii 76K brain cyst burden by 89% in C3H/HeN mice, but no sterile immunity was obtained (Jongert et al 2007).…”

Section: Plasmid Vaccinesmentioning

confidence: 98%

Vaccines against Toxoplasma gondii: challenges and opportunities

Jongert

Roberts

Gargano

et al. 2009

Mem. Inst. Oswaldo Cruz

Self Cite

171

136

View full text Add to dashboard Cite

show abstract

A Combination of Antigenic Regions ofToxoplasma gondiiMicroneme Proteins Induces Protective Immunity against Oral Infection with Parasite Cysts

Cited by 85 publications

References 45 publications

Use of Recombinant Antigens for Early Postnatal Diagnosis of Congenital Toxoplasmosis

Use of Recombinant Antigens for Early Postnatal Diagnosis of Congenital Toxoplasmosis

Chimeric Antigens ofToxoplasma gondii: Toward Standardization of Toxoplasmosis Serodiagnosis Using Recombinant Products

Vaccines against Toxoplasma gondii: challenges and opportunities

Contact Info

Product

Resources

About