Fig. 3. Expression of Bcl-2 protein in transfected U-937/ptsp53 cells. Bcl-2-transfected U-937/ptsp53 clones and wild-type U-937 cells were subjected to IP, followed by Western Blot (IP-Western) using the mouse monoclonal anti-bcl-2-antibody 1550 as described in "Materials and Methods." Arrow on the right, position of Bcl-2 protein at Mr 26,000. Low amounts of Bcl-2 protein were detected in U-937 wild-type cells. Left, positions of molecular weight standards (in thousands).