Figure 3.
Analysis of CD4+ T-cell responses to citGRP78 peptides using in vitro Tmr assays. To identify immunogenic citrullinated peptides derived from GRP78, PBMCs from six patients with type 1 diabetes (T1D) and six healthy control (HC) subjects were expanded for 2 weeks by stimulating with peptide and then stained with the corresponding DRB1*04:01 Tmr. The representative FACS plots depict Tmr+ CD4+ T cells (percentages shown in each upper-right quadrant) directed against the citGRP78 peptide 195–209X (A and B), 498–512X (C and D), or 500–514X (E and F) in HC subjects (A, C, and E) and in patients with T1D (B, D, and F). With use of a previously established cutoff, Tmr staining of twice the mean value of the negative (Neg.) control (Tmr staining of unstimulated T cells) (G) was considered to be a positive response (H).