Use of Recombinant Antigens for Detection of Toxoplasma gondii Infection in Swine

Gamble, H. Ray; Andrews, C.D.; Dubey, J. P.; Webert, Donald W.; Parmley, Stephen

doi:10.2307/3284857

Cited by 10 publications

(14 citation statements)

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“…The major sources of infection for humans are undercooked meat, especially pork and lamb, and contaminated fruit and vegetables (2,3,8,9). Accurate diagnostic assays for the detection of the T. gondii infection in infected animals are crucial as a step toward management and control of the disease.…”

Section: Discussionmentioning

confidence: 99%

“…The latex agglutination test (LAT) is to date considered the gold standard method for diagnosis of T. gondii infection; however, the test has poor specificity (5,6). Enzyme-linked immunosorbent assays (ELISAs) with purified recombinant proteins are widely used for routine diagnostic testing and in seroepidemiological investigations (7)(8)(9). However, the test is expensive, needs specialized facilities in the laboratory, and cannot be used in the field and clinic.…”

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confidence: 99%

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Development of an Immunochromatographic Assay Based on Dense Granule Protein 7 for Serological Detection of Toxoplasma gondii Infection

Terkawi

Kameyama

Rasul

et al. 2013

Clin Vaccine Immunol

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Dense granule antigen proteins derived from Toxoplasma gondii (TgGRAs) are potential antigens for the development of diagnostic tools. TgGRA7 and TgGRA14 were detected in the peritoneal fluid of T. gondii-infected mice, suggesting that TgGRAs may be highly antigenic proteins. Here, TgGRA7 and TgGRA14 were evaluated as candidates for the development of a marker for a rapid diagnostic test. The specificity and sensitivity of purified recombinant proteins of TgGRA7 and TgGRA14 were compared in an indirect enzyme-linked immunosorbent assay (iELISA) using a series of serum samples from T. gondii-experimentally infected mice and using recombinant T. gondii major surface antigen 2 (TgSAG2) as a reference control. The iELISA with TgGRA7 showed the greatest diagnostic accuracy and could detect anti-TgGRA7 antibody in acute and chronic infections. A total of 59 field samples from pigs were also examined by the iELISAs, and the results compared with those of the latex agglutination test (LAT). Among the three recombinant antigens, TgGRA7 had the highest rates of positivity, with significant concordance (88.14) and kappa value (0.76) in comparison with the results using LAT. Furthermore, an immunochromatographic test (ICT) based on recombinant TgGRA7 was developed for rapid detection of antibodies to the infection. The ICT differentiated clearly between sera from T. gondii-infected mice and uninfected or Neospora caninum-infected mice. Pig sera were examined with the ICT, and the results compared favorably with those of LAT and iELISA for TgGRA7, with kappa values of 0.66 and 0.70 to 0.79, respectively. These data suggest that the ICT based on TgGRA7 is a promising diagnostic tool for routine testing in the clinic and mass screening of samples in the field.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Development of an Immunochromatographic Assay Based on Dense Granule Protein 7 for Serological Detection of Toxoplasma gondii Infection

Terkawi

Kameyama

Rasul

et al. 2013

Clin Vaccine Immunol

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“…The MAG1 antigen is a very immunogenic protein. High titers of immunoglobulin G (IgG) antibodies against MAG1 are induced in infected humans and pigs (3,9). Several authors have described the protective effects of MAG1 immunization, as a recombinant protein or as DNA vaccines, in mouse models (19,20).…”

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confidence: 99%

Use of MAG1 Recombinant Antigen for Diagnosis ofToxoplasma gondiiInfection in Humans

Holec

Hiszczyńska-Sawicka

Gasior

et al. 2007

Clin Vaccine Immunol

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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.Toxoplasma gondii (a member of the phylum Apicomplexa) is an ubiquitous protozoan parasite that infects a broad range of hosts, including humans and domestic animals. There are three infectious stages in the life cycle of T. gondii, i.e., the tachyzoite stage; the bradyzoite stage, which occurs in tissue cysts; and the sporozoite stage, which occurs in sporulated oocysts (4). Tachyzoites are involved in propagation within a host, and the other two forms are involved in transmission to new hosts. However, although the ultrastructures of the three stages are similar, there are distinct differences in the phenotypes in the host and in the expression of specific proteins. Several authors have described specific molecular markers associated with both tachyzoites and bradyzoites of T. gondii (7,10). A 65-kDa protein, MAG1, was originally described as being expressed specifically during bradyzoite development because it was localized to the ground substance of the tissue cyst and could be detected in immunoblots of extracts from cysts but not from tachyzoites (21). In 2002, Ferguson and Parmley (6) showed that MAG1 is expressed during both tachyzoite and bradyzoite development and is not a bradyzoite-specific protein. The MAG1 antigen is a very immunogenic protein. High titers of immunoglobulin G (IgG) antibodies against MAG1 are induced in infected humans and pigs (3, 9). Several authors have described the protective effects of MAG1 immunization, as a recombinant protein or as DNA vaccines, in mouse models (19,20). Taken together, these results suggest that matrix antigen MAG1 is particularly promising as a tool for the serodiagnosis of toxoplasmosis in humans.There are two major situations in which the diagnosis of T. gondii infection is of medical importance: first, to detect the transmission of parasites via the placenta from an infected mother to the fetus, and second, to detect the reactivation of a chronic infection in immunocompromised patients. Among the available commercial diagnostic tests, serology is commonly used. The specificities and sensitivities of these serological methods and the differentiation between the phases of t...

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“…Además, la producción de antígenos por medio de tecnología recombinante permite aumentar la cantidad y pureza del antígeno producido, además de acelerar y disminuir los costos de producción. 4,5 Por otra parte, los antígenos de microorganismos peligrosos pueden producirse en organismos inocuos, con lo que se reduce el riesgo de infección durante la producción. 5,6 Entre las pruebas inmunológicas más utilizadas en métodos diagnósticos figuran las de hemaglutinación, inmunodifusión e inmunofluorescencia indirecta (IFI); algunas de éstas constituyen las pruebas de referencia ("estándar de oro") para la detección de agentes patógenos.…”

Section: Detección Específica De Moléculas Mediante Pruebas Inmunológunclassified

Avances biotecnológicos en el diagnóstico de enfermedades infecciosas

Hernández-Hernández¹,

Rodrı́guez²

2009

Salud pública Méx

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The detection of molecules of pathogens (antigens and genetic material) and host molecules in response to infections (antibodies) is the basic principle involved in molecular diagnostic tests. These tests have avoided the need to detect the attacking pathogen. New advances in molecular biology and the development of robotic technology and genomic and protein sequencing have allowed for the development of new high performance and highly specific tests. Genomics and proteomics contribute to the identification of biomarkers and biotechnology provides methods to produce high purity reagents. The identification of coding genes of specific antigens, their cloning and recombinant production, the production of monoclonal antibodies, their fragments and single chain antibodies enabled new, safer, high sensitivity and specificity immunological techniques to develop. New recognition molecules, including aptamers, will soon replace the need to produce antibodies by immunization. For the detection of genetic material, new methodological strategies based on hybridization and amplification (PCR, end point and real time) in multiplex and microarray formats have been developed, and for their detection new reporter molecules have been designed that enable their quantification. Although these methods require sophisticated instrumentation, they will soon be accessible for application in public health.

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Use of Recombinant Antigens for Detection of Toxoplasma gondii Infection in Swine

Cited by 10 publications

References 3 publications

Development of an Immunochromatographic Assay Based on Dense Granule Protein 7 for Serological Detection of Toxoplasma gondii Infection

Development of an Immunochromatographic Assay Based on Dense Granule Protein 7 for Serological Detection of Toxoplasma gondii Infection

Use of MAG1 Recombinant Antigen for Diagnosis ofToxoplasma gondiiInfection in Humans

Avances biotecnológicos en el diagnóstico de enfermedades infecciosas

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