To begin to address this, we sequenced T cell receptor β-chain (TCRB) CDR3 regions of GAD-specific bifunctional T cells obtained from two of the T cell lines (one donor HLA-DRB1*0301/DQA1*0501/DQB1*0201 genotype, one HLA-DRB1*0404/DQA1*0301/DQB1*0302) and matched these against a repository of TCRB CDR3 sequences from circulating naive, and central memory CD4+ T cell subsets that we obtained previously from a separate cohort of non-GAD immunised, new-onset type 1 diabetes individuals and HLA-matched, non-diabetic healthy individuals [18]. Here, GAD1 is linked to type 1 diabetes mellitus.