Effect of proteasome inhibitors on normal lymphocytes. (A) Effects on normal lymphocytes. Isolated peripheral blood lymphocytes from normal donors were incubated in the presence of 10 μmol/L MG132 or 10 μmol/L methylprednisolone with or without 25 μmol/L zAPFcmk for 16 hours, and apoptosis was assessed by PI staining and FACS analysis. Results of one experiment are representative of three independent replicates. (B) Effects on hematopoietic progenitor cells. G-CSF–mobilized CD34⁺CD45⁺ progenitor cells were incubated in the absence or presence of 25 μmol/L zAPFcmk or 10 μmol/L MG-132 and DNA fragmentation was measured after 16 hours by PI staining and FACS analysis.