Conferring HLA-A*02 specificity to CD8⁺ Tregs improves their suppressive capacity on a HLA-A*02-mismatched proliferation in vitro. A2-CAR, Her2-CAR, and NT CD8⁺ Tregs were tested in a range of ratios to CD4⁺ (A) or CD8⁺ (B) Teffs stimulated by allogeneic HLA-A*02⁺ APCs. (Upper left) Schematic depicting cells cocultured and expression of HLA-A*02 target on cells. (Lower left) Representative histograms of CFSE profile in Teffs at day 5 of culture in the absence (filled gray) or in presence of A2-CAR (red line), Her2-CAR (blue line), or nontransduced (green line) CD8⁺ Tregs in a range of ratio Tregs:Teffs. (Right) Relative proportion of proliferating Teff cells normalized to proliferation in the absence of Tregs, in a range of Tregs:Teffs ratios. n = 6-8, as indicated on each figure. Means ± SEM are represented. Two-way RM ANOVA test and Bonferroni posttest, *P < .05; **P < .01; ***P < .001.