Fig. 3. PRL-dependent up-regulation of the Bcl-2 protein. A, Bcl-2 and Bcl-X protein levels were quantified by intracellular stainings of cells incubated for 20 min on ice with the specific mAb diluted in 0.5% saponin/2% FCS/PBS and later revealed with FITC-labeled anti-hamster immunoglobulin antibody. Background signals of irrelevant mAbs were electronically adjusted during cell acquisition. , BaF-3 + IL-3; - - -, W53 + IL-3; , W53 + 1 ng/ml PRL; , W53 + 30 ng/ml PRL. This is one representative of three independent experiments (days 35 of the cell culture). B, Bcl-2 and Bcl-XL protein expression levels were determined by Western blot analysis on total cell extracts of BaF-3 cells + IL-3 and W53 cells + 30 ng/ml PRL, as described in "Materials and Methods."