Performance of recombinant chimeric proteins in the serological diagnosis of Trypanosoma cruzi infection in dogs

PLoS Negl Trop Dis. 2019 Jun 26;13(6):e0007545. doi: 10.1371/journal.pntd.0007545. eCollection 2019 Jun.

Abstract

Background: Dogs are considered sentinels in areas of Trypanosoma cruzi transmission risk to humans. ELISA is generally the method of choice for diagnosing T. cruzi exposure in dogs, but its performance substantially depends on the antigenic matrix employed. In previous studies, our group has developed four chimeric antigens (IBMP-8.1, 8.2, 8.3, and 8.4) and evaluated their potential for diagnosing T. cruzi exposure in humans. For human sera, these chimeric antigens presented superior diagnostic performances as compared to commercial tests available in Brazil, Spain, and Argentina. Therefore, in this study we have evaluated the potential of these antigenic proteins for detection of anti-T. cruzi IgG antibodies in dog sera.

Methodology/principal findings: The IBMP-ELISA assays were optimized by checkerboard titration. Subsequently, the diagnostic potential was validated through analysis of ROC curves and the performance of the tests was determined using double entry tables. Cross-reactivity was also evaluated for babesiosis, ehrlichiosis, dirofilariosis, anaplasmosis, and visceral leishmaniasis. Best performance was shown by IBMP-8.3 and IBMP-8.4, although all four antigens demonstrated a high diagnostic performance with 46 positive and 149 negative samples tested. IBMP-8.3 demonstrated 100% sensitivity, followed by IBMP-8.4 (96.7-100%), IBMP-8.2 (73.3-87.5%), and IBMP-8.1 (50-100%). The highest specificities were achieved with IBMP-8.2 (100%) and IBMP-8.4 (100%), followed by IBMP-8.3 (96.7-97.5%) and IBMP 8.1 (89.1-100%).

Conclusions/significance: The use of chimeric antigenic matrices in immunoassays for anti-T. cruzi IgG antibody detection in sera of infected dogs was shown to be a promising tool for veterinary diagnosis and epidemiological studies. The chimeric antigens used in this work allowed also to overcome the common hurdles related to serodiagnosis of T. cruzi infection, especially regarding variation of efficiency parameters according to different strains and cross-reactivity with other infectious diseases.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Protozoan / blood*
  • Chagas Disease / diagnosis
  • Chagas Disease / veterinary*
  • Dog Diseases / diagnosis*
  • Dogs
  • Immunoglobulin G / blood
  • ROC Curve
  • Recombinant Fusion Proteins / immunology*
  • Sensitivity and Specificity
  • Serologic Tests / methods*
  • Trypanosoma cruzi / immunology*

Substances

  • Antibodies, Protozoan
  • Immunoglobulin G
  • Recombinant Fusion Proteins

Grants and funding

This work was supported by Gonçalo Moniz Institute (Research Excellence Program - PROEP/IGM, Grant: 400904/2013-6; Internal Research Support Program - PIAP Jovem+, Grant: PIAP-001/2017), and in part by the Coordination of Superior Level Staff Improvement - Brazil (CAPES, Grant PROEX 0720/2018). Brazilian National Council for Scientific and Technological Development (CNPq) and Research Support Foundation for the State of Rio de Janeiro (FAPERJ). MGR, NITZ, CMC, ABR and AMJ are research fellows of CNPq. This study was funded by Oswaldo Cruz Foundation- FIOCRUZ; Vice-Presidency of Research and Reference Laboratories (VPPLR/FIOCRUZ) for investing in our research; the European Union Seventh Framework Program Grant 223034 – ChagasEpiNet. Serum samples from panel 3 were collected under the frame of a research sponsored by Bayer Animal Health [27]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.