Highly Effective Serodiagnosis for Chagas' Disease

Abstract

Many proteins of Trypanosoma cruzi, the causative agent of Chagas' disease, contain characteristic arrays of highly repetitive immunogenic amino acid motifs. Diagnostic tests using these motifs in monomeric or dimeric form have proven to provide markedly improved specificity compared to conventional tests based on crude parasite extracts. However, in many cases the available tests still suffer from limited sensitivity. In this study we produced stable synthetic genes with maximal codon variability for the four diagnostic antigens, B13, CRA, TcD, and TcE, each containing between three and nine identical amino acid repeats. These genes were combined by linker sequences encoding short proline-rich peptides, giving rise to a 24-kDa fusion protein which was used as a novel diagnostic antigen in an enzyme-linked immunosorbent assay setup. Validation of the assay with a large number of well-characterized patient sera from Bolivia and Brazil revealed excellent diagnostic performance. The high sensitivity of the new test may allow future studies to use blood collected by finger prick and dried on filter paper, thus dramatically reducing the costs and effort for the detection of T. cruzi infection.

Chronic Chagas Disease Diagnosis: A Comparative Performance of Commercial Enzyme Immunoassay Tests

“…[14][15][16] More recently, chimeric recombinant proteins designed with selected amino acid sequences increased the Se and Sp in diagnostic assays. 17,18 In this scenario, because of the heterogeneity of the performance reported by the tests for Chagas disease diagnosis, we decided to assess the reported quality of four EIA tests for their ability to specifically detect T. cruzi antibodies.…”

Evaluación preliminar de la prueba comercial “Chagas (Trypanosoma cruzi) IgG-ELISA®” en individuos colombianos

“…Esta diversidad en la oferta de pruebas de ELISA, unida a las diferencias en los aislamientos circulantes en cada región, la prevalencia de la enfermedad en cada población y en los protocolos utilizados, resulta en una considerable fuente de variación en una misma prueba y entre pruebas (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20).…”

“…Varios estudios han demostrado la capacidad de estos epítopos de inducir respuesta inmune humoral en el curso de la enfermedad en pacientes con enfermedad de Chagas procedentes de Argentina, Chile, Brasil, Bolivia y Ecuador (13)(14)(15)(16)(17)(18)(19)(20). Además, la evaluación de la ELISA basada en el antígeno TcF en pacientes de Brasil y Argentina mostró porcentajes de sensibilidad y especificidad de 100 y 98,94 %, respectivamente (12).…”

Advances in Serological Diagnosis of Chagas' Disease by Using Recombinant Proteins

“…The studies have been supported by bioinformatic prediction of putative proteins and antigenicity predictors. (Goto et al, 2008;Cooley et al, 2008;Hernandez et al, 2010) Using these tools, it has been possible to choose antigens which display the lowest homology level with proteins of organisms related to T. cruzi. (Hernandez et al, 2010) Moreover, the bioinformatic analysis has allowed describing for the first time a specific antigen to type discrete typing units (DTUs).…”

“…(Goto et al, 2008;Cooley et al, 2008;Hernandez et al, 2010) Using these tools, it has been possible to choose antigens which display the lowest homology level with proteins of organisms related to T. cruzi. (Hernandez et al, 2010) Moreover, the bioinformatic analysis has allowed describing for the first time a specific antigen to type discrete typing units (DTUs). (Di Noia et al, 2002) The results published by many different laboratories point towards considering recombinant proteins as the chosen molecules to be used in immunoassays to diagnose T. cruzi infection.…”