title: Mapping of B-cell epitopes in a Trypanosoma cruzi immunodominant antigen expressed in natural infections.
abstract: Tc40 is an immunodominant antigen present in natural Trypanosoma cruzi infections. This immunogen was thoroughly mapped by using overlapping amino acid sequences identified by gene cloning and chemical peptide synthesis. To map continuous epitopes of the Tc40 antigen, an epitope expression library was constructed and screened with sera from human chagasic patients. A major, linear B-cell epitope spanning residues 403 to 426 (PAKAAAPPAA) was identified in the central domain of Tc40. A synthetic peptide spanning this region reacted strongly with 89.8% of the serum samples from T. cruzi-infected individuals. This indicates that the main antigenic site is defined by the linear sequence of the peptide rather than a conformation-dependent structure. The major B-cell epitope of Tc40 shares a high degree of sequence identity with T. cruzi ribosomal and RNA binding proteins, suggesting the existence of cross-reactivity among these molecules.
authors.affiliation: UMR 2714 CNRS-bioMérieux, IFR 128 BioScience Lyon-Gerland, CERVI-21, Lyon, France.
authors.forename: Mylène
authors.initials: M
authors.lastname: Lesénéchal
authors.forename: Laurence
authors.initials: L
authors.lastname: Becquart
authors.forename: Xavier
authors.initials: X
authors.lastname: Lacoux
authors.forename: Laurent
authors.initials: L
authors.lastname: Ladavière
authors.forename: Renata C P
authors.initials: RC
authors.lastname: Baida
authors.forename: Glaucia
authors.initials: G
authors.lastname: Paranhos-Baccalà
authors.forename: José Franco
authors.initials: JF
authors.lastname: da Silveira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D014355:Chagas Disease / Q000276:immunology*; D003429:Cross Reactions; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000737:chemistry*; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000276:immunology; D012261:Ribonucleoproteins / Q000737:chemistry / Q000276:immunology*; D016415:Sequence Alignment; D014349:Trypanosoma cruzi / Q000276:immunology*
chemical_list: D018985:Epitopes, B-Lymphocyte; D016056:Immunodominant Epitopes; D011993:Recombinant Fusion Proteins; D012261:Ribonucleoproteins