TGF-β1 and TGF-β2 increase ASM α-SMA expression and contractility. Bar chart illustrating the fold change over control of α-SMA GMFI expression by ASM assessed by flow cytometry after culture with TGF-β1 or TGF-β2 (0.25, 2, or 10 ng/ml) (n = 9 ASM donors) (A) or TGF-β1 (2 ng/ml) with or without TGF-β1 neutralizing Ab or appropriate isotype control for 1, 3, or 7 days (n = 3 ASM donors) (B). C, Time course after 100 μM/ml histamine stimulation of collagen gel contraction in gels previously impregnated with TGF-β1 (2 ng/ml) in the presence or absence of TGF-β1 neutralizing Ab or appropriate isotype control for 48 h (n = 3 ASM donors). *, p < 0.05.