Gating strategy and protein expression levels related to Fig. 2 . (A) Upper: Experimental scheme depicting the method of gating Tregs or Raji cells in coculture. Lower: Flow cytometry contour maps or histograms before and after mixing of Tregs and VF-405 prestained Raji cells. (B) Flow cytometry histograms showing the CD28 and CTLA4 total levels on Jurkat (CD28^+/+) and Jurkat (CD28^−/−CTLA4^high) cells. (C) Flow cytometry histograms showing the MHC II (anti–HLA-DR) levels on Jurkat and Raji cells. (D) Flow cytometry histograms showing the CD28 levels on Jurkat (CD28^+/+) and Jurkat (CD28^−/−) cells.