title: Frequency of specific CD8+ T cells for a promiscuous epitope derived from Trypanosoma cruzi KMP-11 protein in chagasic patients.
abstract: The K1 peptide is a CD8(+)T cell HLA-A*0201-restricted epitope derived from the Trypanosoma cruzi KMP-11 protein. We have previously shown that this peptide induces IFN-gamma secretion by CD8(+)T cells. The aim of this study was to characterize the frequency of K1-specific CD8(+)T cells in chagasic patients. Nineteen HLA-A2(+)individuals were selected from 50 T. cruzi infected patients using flow cytometry and SSP-PCR assays. Twelve HLA-A*0201(+)noninfected donors were included as controls. Peripheral blood mononuclear cells were stained with HLA-A2-K1 tetramer, showing that 15 of 19 infected patients have K1-specific CD8(+)T cells (0.09-0.34% frequency) without differences in disease stages or severity. Of note, five of these responders were A*0205, A*0222, A*0226, A*0259 and A*0287 after molecular typing. Thus, a phenotypic and functional comparison of K1-specific CD8(+)T cells from non-HLA-A*0201 and HLA-A*0201(+)infected patients was performed. The results showed that both non-HLA-A*0201 and HLA-A*0201(+)individuals have a predominant effector memory CD8(+)T cell phenotype (CCR7-, CD62L-). Moreover, CD8(+)T cells from non-HLA-A*0201 and HLA-A*0201(+)individuals expressed IL-2, IFN-gamma and perforin without any differences. These findings support that K1 peptide is a promiscuous epitope presented by HLA-A2 supertype molecules and is highly recognized by chagasic patients.
authors.affiliation: Laboratorio de Parasitología Molecular, Pontificia Universidad Javeriana, Bogotá, Colombia.
authors.forename: P
authors.initials: P
authors.lastname: Lasso
authors.forename: D
authors.initials: D
authors.lastname: Mesa
authors.forename: A
authors.initials: A
authors.lastname: Cuéllar
authors.forename: F
authors.initials: F
authors.lastname: Guzmán
authors.forename: N
authors.initials: N
authors.lastname: Bolaños
authors.forename: F
authors.initials: F
authors.lastname: Rosas
authors.forename: V
authors.initials: V
authors.lastname: Velasco
authors.forename: M Del Carmen
authors.initials: Mdel C
authors.lastname: Thomas
authors.forename: M C
authors.initials: MC
authors.lastname: Lopez
authors.forename: J M
authors.initials: JM
authors.lastname: Gonzalez
authors.forename: C J
authors.initials: CJ
authors.lastname: Puerta
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D014355:Chagas Disease / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005260:Female; D005838:Genotype; D015789:HLA-A2 Antigen / Q000235:genetics / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D054353:Perforin / Q000096:biosynthesis; D015800:Protozoan Proteins / Q000276:immunology*; D014349:Trypanosoma cruzi / Q000276:immunology*
chemical_list: D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D007376:Interleukin-2; D015800:Protozoan Proteins; D054353:Perforin; D007371:Interferon-gamma