Fas-ligand expression in CD34⁺ cells. (A) RT-PCR of cells exposed to various doses of IFN-γ showed constitutive expression, no inductive effect of IFN-γ, and repression of fas-L at the 50 ng/mL dose. (B) Immunoblot of CD34⁺ cell lysates probed with anti-fas-L antibody. CD34⁺ cells were incubated in the absence (lanes 1 and 3) or presence (lanes 2 and 4) of IFN-γ for 24 hours (lanes 1 and 2) or 48 hours (lanes 3 and 4). (Each lane was loaded with 50 μg total protein.)