Figure 2.

(a) Representative imaging flow single-cell images depicting bright-field (left column) and melanocortin 1 receptor (MC1R) expression in CD4⁺ and CD8⁺ T cells (right column). (b) Representative plots quantifying membrane MC1R expression on nonpermeabilized CD4⁺ and CD8⁺ T cells compared with isotype staining (negative control), and (c) membrane MC1R quantification as mean florescence intensity (MFI). Data are mean + standard error of the mean (SEM) of 2 independent experiments with 2–4 donors each. (d) Representative plots of FOXP3⁺ T_REG at the end of 5 day-induction assay in the presence of α-melanocyte-stimulating hormone (α-MSH) (bottom) or vehicle control (top). Naïve human CD4⁺CD45RA⁺CD45RO⁻ T cells were cultured with anti-CD3/anti-CD28 mAb (1 μg/ml), interleukin-2 (100 IU/ml), and transforming growth factor-β (10 ng/ml) ± α-MSH. (e) Quantification of FOXP3 expression measured by flow cytometry 5 days later. Data are represented as mean + SEM of 3 different experiments with 3 different donors.