IFNγ-induced Fas expression on lin⁻spleen and bone marrow cells. Flow cytometry analysis was performed on at least 20,000 events gated from the population without lineage markers. Splenocytes (A and B) and bone marrow cells (C and D) were stained directly or after 24 hours of incubation with 100 U/mL of mrIFNγ. The broken line represents control PE-conjugated hamster MoAb.