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. 2021 Oct 5;118(41):e2107208118. doi: 10.1073/pnas.2107208118

Fig. 3.

Fig. 3.

HLA restrictions of preproinsulin and insulin DRiP–reactive CD8 T cells. (A–C) TCR transductants were cultured with or without peptides in the presence of K562 antigen–presenting cells expressing each HLA class I molecule. Peptides contained in one or two peptide pools that induced the strongest response in the screening test were used as stimulus, and responses to each peptide are shown in the order listed in SI Appendix, Table 6a. Peptide sequences are shown in SI Appendix, Table 6b. Responses in the presence of antigen-presenting cells expressing each HLA-A, HLA-B, and HLA-C molecule are shown in red, blue, and green bars, respectively, and HLA alleles tested for each TCR transductant are indicated in SI Appendix, Table 6a. Results for first and second HLA alleles listed in the table are shown in dark and light colors in the figures, respectively. ZsGreen-1 expression levels in wells without peptides are indicated in the most Left bars for each HLA allele. Results for preproinsulin-reactive TCR clonotypes derived from T1D donors, insulin DRiP–reactive TCRs derived from T1D donors, and preproinsulin-reactive TCR clonotypes derived from nondiabetic control donors are shown in panels A, B, and C, respectively. Mean values ± SEM obtained from three independent experiments are plotted, and a determined HLA allele is indicated in the Upper Right corner of each panel. (D) The numbers of clonotypes restricted by HLA-A, -B, and -C molecules are indicated. Individual colors represent TCR clonotypes derived from different donors. (E) Among 21 clonotypes derived from donors having HLA-A*02:01, the numbers of clonotypes restricted by A*02:01 and those restricted by alleles other than A*02:01 are shown. The dashed line indicates an expected probability of restriction by each allele (i.e., 21 divided by 6 possible alleles in each individual). An exact binomial test was used to test whether the proportion of TCR clonotypes restricted with HLA-A*02:01 was equal to 1/6, and this was not the case as 10/21 (48%) restricted to HLA-A*02:01 (P < 0.001).