T cells differentiated with ^HGFMo acquire cell-contact-dependent suppressor activity. (A-B) CD4⁺ T cells activated for 7 days with ^HGFMo in the primary MLR were added to an independently generated MLR, consisting of autologous CD4⁺CD25^- T cells and the same allogeneic GM4-DCs used in the primary MLR (DC/T-cell ratio equal to 1:3). The ratio of DC-activated T cells recovered from the primary MLR to autologous CD4⁺CD25^- T cells plated in the secondary MLR is indicated. Control cultures were established in the absence of added T cells (B). CFSE fluorescence and background staining with isotype-matched fluorochrome-conjugated irrelevant mAbs in unstimulated CD4⁺ T cells are shown in panel A. The PI of alloreactive T cells is reported. One representative experiment of 4 with similar results is shown. (C) CD4⁺ T cells activated with ^HGFMo in the primary MLR were plated in the upper compartment of a Transwell and were restimulated with the same ^HGFMo used in the primary MLR (DC/T-cell ratio equal to 1:3). Autologous unstimulated CD4⁺CD25^- T cells were plated in the lower compartment of the Transwell and were activated with third-party immunogenic GM4-DCs (DC/T-cell ratio equal to 1:3). The PI of alloreactive T cells is reported. One representative experiment of 4 with similar results is shown.