title: Effect of secondary anchor amino acid substitutions on the immunogenic properties of an HLA-A*0201-restricted T cell epitope derived from the Trypanosoma cruzi KMP-11 protein.
abstract: The TcTLE peptide (TLEEFSAKL) is a CD8(+) T cell HLA-A*0201-restricted epitope derived from the Trypanosoma cruzi KMP-11 protein that is efficiently processed, presented and recognized by CD8(+) T cells from chagasic patients. Since the immunogenic properties of wild-type epitopes may be enhanced by suitable substitutions in secondary anchor residues, we have studied the effect of introducing specific mutations at position 3, 6 and 7 of the TcTLE peptide. Mutations (E3L, S6V and A7F) were chosen on the basis of in silico predictions and in vitro assays were performed to determine the TcTLE-modified peptide binding capacity to the HLA-A*0201 molecule. In addition, the functional activity of peptide-specific CD8(+) T cells in HLA-A2(+) chagasic patients was also interrogated. In contrast to bioinformatics predictions, the TcTLE-modified peptide was found to have lower binding affinity and stability than the original peptide. Nevertheless, CD8(+) T cells from chronic chagasic patients recognized the TcTLE-modified peptide producing TNF-α and INF-γ and expressing CD107a/b, though in less extension than the response triggered by the original peptide. Overall, although the amino acids at positions 3, 6 and 7 of TcTLE are critical for the peptide affinity, they have a limited effect on the immunogenic properties of the TcTLE epitope.
authors: Laboratorio de Parasitología Molecular, Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá D.C., Colombia; Grupo de Inmunobiología y Biología Celular, Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá D.C., Colombia; Instituto de Parasitología y Biomedicina López Neyra, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n.18016, Granada, Spain.
authors: Paola
authors: P
authors: Lasso
authors: Núcleo de Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, Curauma, Valparaíso, Chile.
authors: Constanza
authors: C
authors: Cárdenas
authors: Núcleo de Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, Curauma, Valparaíso, Chile.
authors: Fanny
authors: F
authors: Guzmán
authors: Instituto de Arritmias Joseph Brugada, Fundación Clínica Abood Shaio, Diagonal 115A No. 70C-75, Bogotá D.C., Colombia.
authors: Fernando
authors: F
authors: Rosas
authors: Instituto de Parasitología y Biomedicina López Neyra, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n.18016, Granada, Spain.
authors: María Carmen
authors: MC
authors: Thomas
authors: Instituto de Parasitología y Biomedicina López Neyra, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n.18016, Granada, Spain.
authors: Manuel Carlos
authors: MC
authors: López
authors: Grupo de Ciencias Básicas Médicas, Facultad de Medicina, Universidad de los Andes, Carrera 1 No. 18A-10, Bogotá D.C., Colombia.
authors: John Mario
authors: JM
authors: González
authors: Grupo de Inmunobiología y Biología Celular, Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá D.C., Colombia.
authors: Adriana
authors: A
authors: Cuéllar
authors: Departament de Fisicoquímica, Facultat de Farmàcia and Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain.
authors: Josep Maria
authors: JM
authors: Campanera
authors: Departament de Fisicoquímica, Facultat de Farmàcia and Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain.
authors: F Javier
authors: FJ
authors: Luque
authors: Laboratorio de Parasitología Molecular, Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá D.C., Colombia. Electronic address: cpuerta@javeriana.edu.co.
authors: Concepción Judith
authors: CJ
authors: Puerta
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D001665:Binding Sites; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D002460:Cell Line; D014355:Chagas Disease / Q000276:immunology / Q000469:parasitology; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D005786:Gene Expression Regulation; D015789:HLA-A2 Antigen / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology; D052118:Lysosomal-Associated Membrane Protein 1 / Q000235:genetics / Q000276:immunology; D052119:Lysosomal-Associated Membrane Protein 2 / Q000235:genetics / Q000276:immunology; D009154:Mutation; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology* / Q000494:pharmacology; D011485:Protein Binding; D015800:Protozoan Proteins / Q000737:chemistry / Q000276:immunology*; D014349:Trypanosoma cruzi / Q000737:chemistry* / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D018984:Epitopes, T-Lymphocyte; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D052118:Lysosomal-Associated Membrane Protein 1; D052119:Lysosomal-Associated Membrane Protein 2; D010455:Peptides; D015800:Protozoan Proteins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma
keywords: CD8(+) T cells; Chagas disease; MHC class I; Peptides