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

V Öling, J Marttila, J Ilonen, WW Kwok, G Nepom… - Journal of …, 2005 - Elsevier
V Öling, J Marttila, J Ilonen, WW Kwok, G Nepom, M Knip, O Simell, H Reijonen
Journal of autoimmunity, 2005Elsevier
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 …
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.
Elsevier