Fig. 4.

SLAMF3 costimulation promotes the differentiation of human naïve CD4⁺ T cells into functional Tregs. Isolated naïve CD4⁺ T cells were cultured under Th1, Th2, Th17, and Treg polarizing conditions for 6 d. Intracellular cytokine staining was performed after 6 h of stimulation with PMA and ionomycin. Foxp3 was assessed after nuclear permeabilization for Treg differentiation. (A) Representative flow plots. (B) Cumulative data (mean ± SEM); n = 5–8. Human naïve CD4⁺ T cells were coactivated in the presence of anti-SLAMF3 mAb (solid line) or an isotype control (dashed line) and polarized under Treg conditions. After 6 d, increasing ratios of induced Tregs were cocultured in the presence of CFSE-labeled Tconv cells. Tconv proliferation was assessed after 5 d of coculture. (C) Representative flow plots. (D) Cumulative data (mean ± SEM); n = 7.