Intracellular expression of IL-2Rγ in the different lymphocyte populations. (A) After cell permeabilization, intracellular staining was performed against IL-2Rγ and Bcl-2 protein as positive control. Two-color flow cytometry was performed on PBMC isolated from blood collected on sodique heparin for the upper and lower left panels. Results were confirmed for NK cells on purified CD56 cells as indicated (lower middle panel). Lower right panel shows a positive (YT) and a negative B-EBV cell line (B) derived from a XSCID child; background controls are identical with these two cell lines. (B) Blood was collected on sodique heparin and PBMC were isolated at d = 0. PBL, CD4 T lymphocytes and monocytes were purified and Western blots performed on their lysates as explained in Materials and Methods. Lane 1, YT cell line (positive control); lane 2, B-EBV cell line from a XSCID patient (negative control); lane 3, PBMC; lane 4, PBL; lane 5, monocytes; and lane 6, CD4 T lymphocytes.