HTLV-1–infected cells express increased amounts of c-FLIP. (A) Surface expression of CD95 on HuT-102, MT-2, and SLB-1 cells. CEM and H9 cells served as positive controls. Filled histograms represent the isotype control; open histograms represent CD95 surface expression. (B) Expression of components of the CD95 signaling pathway in HTLV-1–infected cells. Lysates of CEM, H9, HuT-102, MT-2, and SLB-1 cells were subjected to SDS-PAGE and Western blot analysis with antibodies against c-FLIP, FADD, caspase-8, Bcl-x_L, and Bcl-2. Analysis of Erk expression served as control for equal protein loading.