The disclosure provides polypeptides that specifically bind to HLA-DQ8 for treating Type 1 Diabetes (TID) and methods using same for reducing autoimmune destruction of pancreatic islet beta cells. In particular, the present disclosure relates to peptides containing at least one D-amino acid that are capable of blocking the presentation of antigenic islet peptides (e.g., lnsB:9-23) by HLA-DQ8, and to their uses, especially as it relates to the prevention and/or treatment of TID.