Fig. 2

EGFR inhibition leads to complement activation in sensitive cell lines. (a) Immunofluorescence microscopy (IFM) shows deposition of complement activation fragments C3 (green) and terminal complement complex TCC (red) on surface of sensitive cell lines HN5 and HN8 after 48 h of Iressa treatment and subsequent incubation with normal human serum (NHS). (b) whereas no change in deposition of C3 or TCC is seen in resistant cell lines HN4 and HN7. Heat-inactivated serum (HIS) was used as a negative control. Scale bars, 10 μM. (c) IFM quantification of terminal complement complex (TCC) deposition on cell lines after 48 h of EGFR stimulation (TGF-a) or inhibtion (Iressa), and subsequent incubation with NHS. Control incubated with NHS was set to 100%. Error bars represent standard deviation. * p < 0.05, ** p < 0.01