Prediction of HLA class I-restricted T-cell epitopes of islet autoantigen combined with binding and dissociation assays.

Identification of cognate peptides recognized by human leucocyte antigen (HLA)/T cell receptor (TCR) complex provides insight into the pathogenic process of type 1 diabetes (T1D). We hypothesize that HLA-binding assays alone are inadequate metrics for the affinity of peptides. Zinc transporter-8 (ZnT8) has emerged in recent years as a novel, major, human autoantigen. Therefore, we aim to identify the HLA-A2-restricted ZnT8 epitopes using both binding and dissociation assays. HLA class I peptide affinity algorithms were used to predict candidate ZnT8 peptides that bind to HLA-A2. We analyzed 15 reported epitopes of seven β-cell candidate autoantigens and eight predicted candidate ZnT8 peptides using binding and dissociation assays. Using IFN-γ ELISpot assay, we tested peripheral blood mononuclear cells (PBMCs) from recent-onset T1D patients and healthy controls for reactivity to seven reported epitopes and eight candidate ZnT8 peptides directly ex vivo. We found five of seven recently reported epitopes in ...