Fig. (2) Stat3 activation is CD45 resistant in the malignant T cells. (A) Malignant T cells (MyLa2000) were incubated for 90 minutes with medium or platebound rabbit anti-mouse (RαM), anti-CD45 or isotype control Abs. Then, the cells were lysed and the total cell lysates analysed by western blotting using anti-pY-Stat3, anti-Stat3 and anti-Erk-1/2 (loading control) Abs. (B) Non-malignant (MyLa1928) and malignant (MyLa2000) T cells were co-stained with Alexa flour 488 conjugated anti-pYStat3 and anti-CD45-PE mAbs or respective conjugated isotype control mAbs. The level of pYStat3 was measured by flow cytometry in the total cell population (CD45^Total) together with pYStat3 levels in the 10% highest (CD45^Low) and lowest (CD45^Neg) CD45 expressing cells.