Figure 5

Scatchard analysis of (¹²⁵I)TGF-β1 binding to N-SP and CLP-SP fibroblasts treated or not with RA. The cells were preincubated at 37 °C for 2 h in serum-free medium containing 0.1% BSA, 25 mM Hepes, pH 7.4, then incubated at 4 °C for 3 h in serum-free medium containing TGF-β1. Cell monolayers were than washed with ice-cold Hanks buffered saline containing 0.1% BSA, 1% Triton X-100, 10% glycerol, and 20 mM Hepes, pH 7.4. Specifically bound (B) and free (F) ligands were measured as described in Materials and Methods. C and RA represent untreated and 10 µM RA-treated fibroblasts, respectively. Data are from a representative determination. Similar results were seen in 4 independent experiments for each of the 4 patients; each experiment was performed in quadruplicate.