Bcl-Xl and Bcl-2 are maintained in HCD57-SREI cells when EPO is withdrawn. HCD57 cells (lanes A, B, E, and F) and HCD57-SREI cells (lanes C, D, G, and H) were cultured for 72 hours in either medium containing 1 U EPO/mL (lanes B, D, F, H) or no EPO (lanes A, C, E, G). Ten micrograms of cellular protein was analyzed by Western blotting using anti-Bcl-Xl (lanes A through D) or anti–Bcl-2 (lanes E through H) antisera. The proteins of interest were visualized with ECL and are marked by an arrow.