GAD-specific T cells display different TCR avidities. (A) PBMCs from a patient with type 1 diabetes were stimulated with 10 μg/mL GAD_555-567 peptide for 10 days and subsequently on GAD-loaded plate-bound MHC monomer and soluble anti-CD28 mAb for an additional 5 days. Control and GAD TMr staining of PBMCs after in vitro expansion is shown. Dashed boxes indicate the cytometry gates for high and low tetramer-binding populations. (B) GAD TMr^high and GAD TMr^low T-cell populations were single-cell sorted from the dashed areas indicated in panel A and further expanded. GAD TMr (black profiles) versus control TMr (dashed profiles) staining of representative clonal populations obtained are shown. Percents of GAD TMr⁺ cells are indicated. (C) TCR and CD4 expression in GAD TMr^high (black profiles) and TMr^low (gray profiles) T cells.