A. AT-MSCs were cultured in the labelling media containing [35S]-Met/Cys and increasing concentrations of r.h. TGF-β1 at 0, 0.1, 0.3, 1, 3 and 10 ng/ml for overnight. Supernatants were harvested and incubated with TGF-β1 capture antibody. After washing the captured TGF-β1 was transferred to glass filter membrane, and the radioactivity was counted with a scintillation counter (black bars). The supernatants were incubated with new TGF-β1 capture antibody, and the radioactivity of captured TGF-β1 was counted again (white bars). The data is given as mean ± SD of 5 repeated measurements. CPM, count per minute. 