title: GAD65- and proinsulin-specific CD4+ T-cells detected by MHC class II tetramers in peripheral blood of type 1 diabetes patients and at-risk subjects.
abstract: In type 1 diabetes the major loss of insulin producing beta-cells is caused by autoreactive T-cells specific for antigens expressed by the pancreatic islets. In this study we have analyzed the prevalence of glutamate decarboxylase 65 (GAD65)- and proinsulin-specific CD4(+) T-cells in type 1 diabetes patients, at-risk subjects and in HLA-matched control children. Peripheral blood mononuclear cells were cultured in the presence of two different GAD65 peptides (555-567, 557I and 274-286) or with a proinsulin (B24-C36) peptide for 10-11days. The autoreactive T-cells were detected using antigen specific-MHC class II tetramers by flow cytometry. Our results show that 11 of 18 (61%) type 1 diabetes patients and 7 of the 20 (35%) at-risk subjects were positive for one of the three GAD65 or proinsulin-containing tetramers, whereas only 2 of 21 (9.5%) controls had tetramer binding cells (p = 0.0007 type 1 diabetes vs. controls and p = 0.0488 at-risk subjects vs. controls, Chi-square test). Type 1 diabetes patients responded to all three peptides. At-risk subjects recognized also the GAD65 555-567 557I peptide, while none of the controls responded to it. In conclusion, type 1 diabetes patients and at-risk subjects have a significantly higher prevalence of GAD65- and proinsulin-specific CD4(+) T-cells than the control subjects.
authors.affiliation: Department of Virology, University of Turku, Medicity, Biocity 4 krs., Tykistökatu 6 A, 20520 Turku, Finland. viveka.oling@utu.fi
authors.forename: Viveka
authors.initials: V
authors.lastname: Oling
authors.forename: Jane
authors.initials: J
authors.lastname: Marttila
authors.forename: Jorma
authors.initials: J
authors.lastname: Ilonen
authors.forename: William W
authors.initials: WW
authors.lastname: Kwok
authors.forename: Gerald
authors.initials: G
authors.lastname: Nepom
authors.forename: Mikael
authors.initials: M
authors.lastname: Knip
authors.forename: Olli
authors.initials: O
authors.lastname: Simell
authors.forename: Helena
authors.initials: H
authors.lastname: Reijonen
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000097:blood / Q000276:immunology*; D005968:Glutamate Decarboxylase / Q000097:blood / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000097:blood*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007527:Isoenzymes / Q000097:blood / Q000276:immunology*; D010446:Peptide Fragments / Q000097:blood / Q000276:immunology; D011384:Proinsulin / Q000097:blood / Q000276:immunology*; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D018984:Epitopes, T-Lymphocyte; D000949:Histocompatibility Antigens Class II; D007527:Isoenzymes; D010446:Peptide Fragments; D011384:Proinsulin; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2