Chagas disease-specific antigens: characterization of epitopes in CRA/FRA by synthetic peptide mapping and evaluation by ELISA-peptide assay.

Publisher: BioMed Central Country of Publication: England NLM ID: 100968551 Publication Model: Electronic Cited Medium: Internet ISSN: 1471-2334 (Electronic) Linking ISSN: 14712334 NLM ISO Abbreviation: BMC Infect Dis Subsets: MEDLINE

Original Publication: London : BioMed Central, [2001-

Antigens, Protozoan/*chemistry ; Antigens, Protozoan/*immunology ; Chagas Disease/*parasitology ; Enzyme-Linked Immunosorbent Assay/*methods ; Trypanosoma cruzi/*immunology; Amino Acid Sequence ; Antibodies, Protozoan/immunology ; Antigens, Protozoan/genetics ; Chagas Disease/diagnosis ; Chagas Disease/immunology ; Enzyme-Linked Immunosorbent Assay/instrumentation ; Epitope Mapping ; Female ; Humans ; Male ; Molecular Sequence Data ; Peptide Mapping ; Peptides/chemical synthesis ; Peptides/genetics ; Peptides/immunology ; Trypanosoma cruzi/chemistry ; Trypanosoma cruzi/genetics

Background: The identification of epitopes in proteins recognized by medically relevant antibodies is useful for the development of peptide-based diagnostics and vaccines. In this study, epitopes in the cytoplasmic repetitive antigen (CRA) and flagellar repetitive antigen (FRA) proteins from Trypanosoma cruzi were identified using synthetic peptide techniques and pooled sera from Chagasic patients. The epitopes were further assayed with an ELISA assay based on synthetic peptides.
Methods: Twenty-two overlapping synthetic peptides representing the coding sequence of the T. cruzi CRA and FRA proteins were assessed by a Spot-synthesis array analysis using sera donated by patients with Chagas disease. Shorter peptides were selected that represented the determined epitopes and synthesized by solid phase synthesis to evaluate the patterns of cross-reactivities and discrimination through an ELISA-diagnostic assay.
Results: The peptide Spot-synthesis array successfully identified two IgG antigenic determinants in the CRA protein and four in FRA. Bioinformatics suggested that the CRA antigens were unique to T. cruzi while the FRA antigen showed similarity with sequences present within various proteins from Leishmania sp. Subsequently, shorter peptides representing the CRA-1, CRA-2 and FRA-1 epitopes were synthesized by solid phase synthesis and assayed by an ELISA-diagnostic assay. The CRA antigens gave a high discrimination between Chagasic, Leishmaniasis and T. cruzi-uninfected serum. A sensitivity and specificity of 100% was calculated for CRA. While the FRA antigen showed a slightly lower sensitivity (91.6%), its specificity was only 60%.
Conclusions: The epitopes recognized by human anti-T. cruzi antibodies have been precisely located in two biomarkers of T. cruzi, CRA and FRA. The results from screening a panel of patient sera through an ELISA assay based on peptides representing these epitopes strongly suggest that the sequences from CRA would be useful for the development of diagnostic reagents that could improve upon the sensitivity and specificity of currently available diagnostic tests. Overall, the results provide further evidence of the usefulness of identifying specific linear B-cell epitopes for improving diagnostic tools.

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0 (Antibodies, Protozoan)
0 (Antigens, Protozoan)
0 (Peptides)
0 (cytoplasmic antigen, Trypanosoma)

Date Created: 20131205 Date Completed: 20140623 Latest Revision: 20211021

20240104

PMC3890492

10.1186/1471-2334-13-568

24299278