Western blot analysis of CD23 after stimulation of IL-4, GM-CSF, IL-4/GM-CSF. Alpha-smooth muscle isoactin positive huASMC (Clonetics) in T-75 flasks were starved for 24 h in 0.1% FBS containing medium M199. The cells were then stimulated with BSA (1 μg/ml) (vehicle control), IL-4 (0.5 nM), GM-CSF (0.4 nM), or IL-4/GM-CSF (0.5 nM/0.4 nM) for 24 h. The cell lysates in RIPA buffer were subjected to western blot analysis for CD23. Mouse anti-human CD23 monoclonal antibody (clone M-L233, BD Biosciences, 1 μg/5 ml) was used as the primary antibody and anti-mouse horseradish peroxidase linked antibody as the secondary antibody (Amersham). The immunoreactive protein bands were detected by enhanced chemiluminescence light (ECL) (Amersham). Paxillin mouse monoclonal IgG1 (Transduction Laboratories) was used as an irrelevant isotype control.