The conformation of purified Toxoplasma gondii SAG1 antigen, secreted from engineered Pichia pastoris, is adequate for serorecognition and cell proliferation

Biemans, Ralph; Gregoire, D.; Haumont, Michèle; Bosseloir, Alain; Garcia, Lida; Jacquet, Alain; Dubeaux, Christine; Bollen, Alex

doi:10.1016/s0168-1656(98)00143-6

Cited by 39 publications

(29 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, these proteins do not contain contaminants derived from the bacterial cells and, therefore, do not give cross-reactions with human sera. In recent years, the Pichia expression system in particular has been used successfully to produced numerous T. gondii recombinant antigens (22,24,75,(80)(81)(82)(83). Thus, there is a need to obtain the new recombinant antigens in different eukaryotic expression systems.…”

Section: Resultsmentioning

confidence: 99%

Toxoplasma gondii Recombinant Antigens as Tools for Serodiagnosis of Human Toxoplasmosis: Current Status of Studies

Holec-Gąsior

2013

Clin Vaccine Immunol

112

105

View full text Add to dashboard Cite

Toxoplasma gondii is a parasitic protozoan which is the cause of toxoplasmosis. Although human toxoplasmosis in healthy adults is usually asymptomatic, serious disease can occur in the case of congenital infections and immunocompromised individuals. Furthermore, despite the exact recognition of its etiology, it still presents a diagnostic problem. Diagnosis of toxoplasmosis is mainly based on the results of serological tests detecting anti-T. gondii-specific antibodies in the patient's serum sample. The specificities and sensitivities of serology tests depend mostly on the diagnostic antigen(s) used. Most of the commercial serological kits currently available are based on Toxoplasma lysate antigens (TLAs). In recent years, many studies showed that recombinant antigenic proteins of T. gondii may be an alternative source of antigens which are very useful for the serodiagnosis of toxoplasmosis. This article presents a review of current studies on the application and usefulness of different T. gondii recombinant antigens in serological tests for the diagnosis of human toxoplasmosis.

show abstract

Section: Resultsmentioning

confidence: 99%

Toxoplasma gondii Recombinant Antigens as Tools for Serodiagnosis of Human Toxoplasmosis: Current Status of Studies

Holec-Gąsior

2013

Clin Vaccine Immunol

112

105

View full text Add to dashboard Cite

show abstract

“…Animals infected with N. caninum reacted strongly to Ncp29 while those infected with T. gondii showed negative ELISA titers. Proteins Ncp29 and SAG1 (also known as p30) from T. gondii have approximately 50% identity at the amino acid level, and both contain 12 cysteine residues that are predicted to be involved in the conformational folding of the protein, a property that is likely important for the highly antigenic nature of SAG1 (5,7,24). Following infection with T. gondii, antibodies to SAG1 appear very early and include immunoglobulin M (IgM) and IgA, as well as IgG classes (10,34), making this Table 1.…”

Section: Resultsmentioning

confidence: 99%

Sensitive and Specific Identification ofNeospora caninumInfection of Cattle Based on Detection of Serum Antibodies to Recombinant Ncp29

Howe

Tang

Conrad³

et al. 2002

Clin Vaccine Immunol

View full text Add to dashboard Cite

Neosporosis is an economically important disease of dairy cattle caused by the protozoan Neospora caninum. Diagnostic tests for neosporosis are complicated by the potential for cross-reaction of antibodies to antigens that are similar between N. caninum and closely related parasites Toxoplasma gondii and Sarcocystis cruzi. To provide a sensitive and specific assay for detecting antibodies to N. caninum in the serum of infected animals, we have investigated a recombinant form of the antigen known as Ncp29 (rNcp29), which is a major surface protein of the parasite. Ncp29 is encoded by a gene that is homologous to the SAG1 gene previously characterized from T. gondii. An enzyme-linked immunosorbent assay (ELISA) was used to screen animals for the presence of serum antibodies specific to rNcp29. The rNcp29 ELISA readily distinguished between cattle known to be infected with N. caninum (optical density [OD] > 1.2 at 1:500 or greater dilution) and negative controls (OD < 0.5 at 1:500). Additionally, sera from animals that were infected with T. gondii or S. cruzi were negative. The rNcp29 ELISA developed here provides a specific and sensitive assay for detecting neosporosis in cattle.

show abstract

“…An effective vaccine against human T. gondii infection is desirable, and SAG1 is one of the most promising vaccine candidates (4,10,26). However, toxoplasmosis is also problematic in an immunocompromised host, and passive immunization may be useful in such a host due to reduced cellular immunity.…”

Section: Discussionmentioning

confidence: 99%

Generation of a Neutralizing Human Monoclonal Antibody Fab Fragment to Surface Antigen 1 ofToxoplasma gondiiTachyzoites

Feng

Ohnishi

et al. 2011

Infect Immun

View full text Add to dashboard Cite

A combinatorial immunoglobulin gene library was constructed from lymphocytes in peripheral blood of a patient with toxoplasmosis and screened for production of human monoclonal antibody Fab fragments to recombinant surface antigen 1 (SAG1) of Toxoplasma gondii. Two Fab clones, Tox203 and Tox1403, which consisted of a common heavy chain and different light chains, showed positive staining on the entire surface of tachyzoites in confocal microscopy. Sequence analysis of the heavy-chain gene revealed that the closest germ line V segments were VH3-23. The germ line D segment was D1-7, and the closest germ line J segment was JH4. In the light-chain genes, the closest germ line V segment was V1-17 with the J1 or J4 segments. The dissociation constants of these Fab fragments with recombinant SAG1 were 3.09 ؋ 10 ؊9 M for Tox203 and 2.01 ؋ 10 ؊8 M for Tox1403, indicating that the affinity of Tox203 was 7 times higher than that of Tox1403. Preincubation of T. gondii tachyzoites with Tox203 significantly inhibited their attachment to cultured MDBK cells. Passive immunization of mice with Tox203 also significantly reduced mortality after challenge with T. gondii tachyzoites. This is the first report of bacterial expression of human monoclonal antibody Fab fragments to SAG1 of T. gondii. These results also demonstrate that human Fab fragments to SAG1 might be applicable for immunoprophylaxis of toxoplasmosis.Toxoplasma gondii is an obligate intracellular parasite in the phylum Apicomplexa and infects a variety of warm-blooded domestic and wild animals worldwide. It is an important foodborne parasite transmitted primarily from animals to humans through meat, as well as through oocysts shed by cats into the environment (25). Infection in humans is usually asymptomatic in immunocompetent hosts. However, primary infection during pregnancy can result in severe neonatal malformations and ocular complications in the fetus. In immunocompromised hosts such as patients with human immunodeficiency virus/ AIDS, reactivation of the latent infection results in symptomatic diseases such as toxoplasmic encephalitis (14,22). Transmission of T. gondii by organ transplantation from a seropositive donor to a seronegative recipient is also an important potential cause of disease in heart, heart-lung, kidney, liver, and liver-pancreas transplant patients (25).The surface of T. gondii is the first component to contact the host cells. The T. gondii surface is coated by closely related antigens that belong to the surface antigen 1 (SAG1)-related sequences (SRS) superfamily (13, 16). SAG1 is the most abundant and immunogenic of these antigens and is important for the process of invasion. Treatment of T. gondii with mouse monoclonal or rabbit polyclonal antibodies to SAG1 inhibits parasite attachment to host cells (24). Fab fragments derived from a mouse monoclonal antibody also showed dose-dependent inhibition of parasite attachment (23). Therefore, human monoclonal antibodies to SAG1 may be applicable for prevention of transmission and reactivation ...

show abstract

The conformation of purified Toxoplasma gondii SAG1 antigen, secreted from engineered Pichia pastoris, is adequate for serorecognition and cell proliferation

Cited by 39 publications

References 29 publications

Toxoplasma gondii Recombinant Antigens as Tools for Serodiagnosis of Human Toxoplasmosis: Current Status of Studies

Toxoplasma gondii Recombinant Antigens as Tools for Serodiagnosis of Human Toxoplasmosis: Current Status of Studies

Sensitive and Specific Identification ofNeospora caninumInfection of Cattle Based on Detection of Serum Antibodies to Recombinant Ncp29

Generation of a Neutralizing Human Monoclonal Antibody Fab Fragment to Surface Antigen 1 ofToxoplasma gondiiTachyzoites

Contact Info

Product

Resources

About