title: Identification of strain-specific B-cell epitopes in Trypanosoma cruzi using genome-scale epitope prediction and high-throughput immunoscreening with peptide arrays.
abstract: BACKGROUND
  The factors influencing variation in the clinical forms of Chagas disease have not been elucidated; however, it is likely that the genetics of both the host and the parasite are involved. Several studies have attempted to correlate the T. cruzi strains involved in infection with the clinical forms of the disease by using hemoculture and/or PCR-based genotyping of parasites from infected human tissues. However, both techniques have limitations that hamper the analysis of large numbers of samples. The goal of this work was to identify conserved and polymorphic linear B-cell epitopes of T. cruzi that could be used for serodiagnosis and serotyping of Chagas disease using ELISA.
  
  
  METHODS
  By performing B-cell epitope prediction on proteins derived from pair of alleles of the hybrid CL Brener genome, we have identified conserved and polymorphic epitopes in the two CL Brener haplotypes. The rationale underlying this strategy is that, because CL Brener is a recent hybrid between the TcII and TcIII DTUs (discrete typing units), it is likely that polymorphic epitopes in pairs of alleles could also be polymorphic in the parental genotypes. We excluded sequences that are also present in the Leishmania major, L. infantum, L. braziliensis and T. brucei genomes to minimize the chance of cross-reactivity. A peptide array containing 150 peptides was covalently linked to a cellulose membrane, and the reactivity of the peptides was tested using sera from C57BL/6 mice chronically infected with the Colombiana (TcI) and CL Brener (TcVI) clones and Y (TcII) strain.
  
  
  CONCLUSIONS
  A total of 36 peptides were considered reactive, and the cross-reactivity among the strains is in agreement with the evolutionary origin of the different T. cruzi DTUs. Four peptides were tested against a panel of chagasic patients using ELISA. A conserved peptide showed 95.8% sensitivity, 88.5% specificity, and 92.7% accuracy for the identification of T. cruzi in patients infected with different strains of the parasite. Therefore, this peptide, in association with other T. cruzi antigens, may improve Chagas disease serodiagnosis. Together, three polymorphic epitopes were able to discriminate between the three parasite strains used in this study and are thus potential targets for Chagas disease serotyping.
authors.affiliation: Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
authors.forename: Tiago Antônio de Oliveira
authors.initials: TA
authors.lastname: Mendes
authors.forename: João Luís
authors.initials: JL
authors.lastname: Reis Cunha
authors.forename: Rodrigo
authors.initials: R
authors.lastname: de Almeida Lourdes
authors.forename: Gabriela Flávia
authors.initials: GF
authors.lastname: Rodrigues Luiz
authors.forename: Lucas Dhom
authors.initials: LD
authors.lastname: Lemos
authors.forename: Ana Rita Rocha
authors.initials: AR
authors.lastname: dos Santos
authors.forename: Antônia Cláudia Jácome
authors.initials: AC
authors.lastname: da Câmara
authors.forename: Lúcia Maria da Cunha
authors.initials: LM
authors.lastname: Galvão
authors.forename: Caryn
authors.initials: C
authors.lastname: Bern
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.forename: Ricardo Toshio
authors.initials: RT
authors.lastname: Fujiwara
authors.forename: Ricardo Tostes
authors.initials: RT
authors.lastname: Gazzinelli
authors.forename: Daniella Castanheira
authors.initials: DC
authors.lastname: Bartholomeu
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology / Q000302:isolation & purification; D014355:Chagas Disease / Q000175:diagnosis*; D019295:Computational Biology / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D040081:Protein Array Analysis / Q000379:methods*; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods; D014349:Trypanosoma cruzi / Q000235:genetics / Q000276:immunology*
chemical_list: D000953:Antigens, Protozoan; D018985:Epitopes, B-Lymphocyte