title: Epitope mapping of a single repetitive unit of the B13 Trypanosoma cruzi antigen as fusions to Escherichia coli LamB protein.
abstract: B13, one of the immunodominant antigens of Trypanosoma cruzi, is composed of repeats of a 12-amino-acid motif. Using synthetic peptides, the sequence FGQAAAGDK was previously shown to contain the B13 immunodominant epitope recognized by chagasic patients sera. To investigate the effects of neighboring sequences in the immunodominance, we tested serum recognition of two B13 sequences fused to LamB. GDKPSPFGQAAA-LamB and FGQAAAGDKPSP-LamB were recognized, respectively, by 15% and 80% of 80 sera reactive to B13 antigen. Recognition of FGQAAAGDKPSP-LamB was inhibited by AAAGDK-containing synthetic peptides. FGQAAAGDKPSP-LamB competed with a B13 recombinant protein containing 16.6 repeats for binding to chagasic antibodies. These results strengthen previous conclusions on the immunodominant epitope of B13 and provide a comparison of two methods for epitope mapping.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, UNIFESP, Rua Botucatu 862, CEP 04023-062 São Paulo, SP, Brazil. pereiracm@ecb.epm.br
authors.forename: Cátia M
authors.initials: CM
authors.lastname: Pereira
authors.forename: José
authors.initials: J
authors.lastname: Franco da Silveira
authors.forename: Márcia
authors.initials: M
authors.lastname: Duranti
authors.forename: Edécio
authors.initials: E
authors.lastname: Cunha-Neto
authors.forename: Bianca
authors.initials: B
authors.lastname: Zingales
authors.forename: Beatriz A
authors.initials: BA
authors.lastname: Castilho
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D014355:Chagas Disease / Q000276:immunology / Q000469:parasitology; D018604:Epitope Mapping / Q000379:methods; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology; D021382:Protein Sorting Signals / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics / Q000276:immunology*; D014349:Trypanosoma cruzi / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D029968:Escherichia coli Proteins; D016056:Immunodominant Epitopes; C085044:LamB signal peptide, E coli; D010455:Peptides; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins