MFB-F11 cells are specific for TGF-βs. A: MFB-F11 cells (4 × 104/well) were stimulated with the indicated concentrations of TGF-β1, 2 and 3. Note the logarithmic scale. B: MFB-F11 cells (4 × 104/well) were stimulated with 0.1 ng (TGF-β1, 2, 3) or 10 ng (activin B, nodal, BMP2, BMP6, BDNF, bFGF) of growth factors. SEAP activity was measured after 24 h as described in Figure 2. Bars represent mean ± SEM of triplicate wells from 1 representative experiment. ** P < 0.001, Student's t test compared to control.