Journal article
Immunoblot Assay Using Recombinant Antigens as a Supplemental Test To Confirm the Presence of Antibodies to Trypanosoma cruzi
Clinical and vaccine immunology, Vol.14(4), pp.355-361
02/07/2007
DOI: 10.1128/CVI.00401-06
PMCID: PMC1865615
PMID: 17287316
Abstract
The diagnosis of chronic Chagas' disease is generally made by detecting antibodies to
Trypanosoma cruzi
. Most conventional serological tests are based on lysates of whole parasites or semipurified antigen fractions from
T. cruzi
epimastigotes grown in culture. The occurrence of inconclusive and false-positive results has been a persistent problem with the conventional assays, and there is no universally accepted gold standard for confirmation of positive test results. We describe here an immunoblot assay for detecting antibodies to
T. cruzi
in which four chimeric recombinant antigens (rAgs), designated FP3, FP6, FP10, and TcF, are used as target antigens. Each of these rAgs is composed of several antigenically distinct regions and includes repetitive as well as nonrepetitive sequences. Each rAg is coated as a discrete line on a nitrocellulose strip. Assay sensitivity was assessed by testing 345 specimens known to be positive for antibodies to
T. cruzi
. All 345 of these samples showed two to four reactive test bands in addition to the three on-board control bands that are on each strip. Assay specificity was determined by testing 500 specimens from random U.S. blood donors, all of which gave negative results. Based on the results obtained in this study, we propose the following scheme for interpretation of test results: (i) no bands or a single test band = a negative result; (ii) two or more test bands with at least one band showing intensity of 1+ or higher = a positive result; and (iii) multiple faint test bands (±) = indeterminate result. Based on this scheme, the prototype immunoblot assay showed sensitivity of 100% (
n
= 345) and specificity of 100% (
n
= 500). Additionally, all 269 potentially cross-reacting and
T. cruzi
antibody-negative specimens tested negative in our immunoblot assay. The rAg-based immunoblot assay has potential as a supplemental test for confirming the presence of antibodies to
T. cruzi
in blood specimens and for identifying false-positive results obtained with other assays.
Details
- Title: Subtitle
- Immunoblot Assay Using Recombinant Antigens as a Supplemental Test To Confirm the Presence of Antibodies to Trypanosoma cruzi
- Creators
- Kevin Y. Cheng - University of IowaChi-Deu Chang - University of IowaVince A. Salbilla - University of IowaLouis V. Kirchhoff - University of IowaDavid A. Leiby - American Red CrossGerald Schochetman - Emerging Pathogens InstituteDinesh O. Shah - Emerging Pathogens Institute
- Resource Type
- Journal article
- Publication Details
- Clinical and vaccine immunology, Vol.14(4), pp.355-361
- DOI
- 10.1128/CVI.00401-06
- PMID
- 17287316
- PMCID
- PMC1865615
- NLM abbreviation
- Clin Vaccine Immunol
- ISSN
- 1556-6811
- eISSN
- 1556-679X
- Publisher
- American Society for Microbiology
- Language
- English
- Date published
- 02/07/2007
- Academic Unit
- Psychiatry; Infectious Diseases; Epidemiology; Internal Medicine
- Record Identifier
- 9984280833902771
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