Fig. 4.

Chondroitin sulfate inhibits TGF-β bioactivity in preterm human milk. A: chondroitin sulfate inhibited the biological activity of endogenous TGF-β in a dose-dependent fashion. Bar diagram (means ± SE) shows TGF-β bioactivity (pM) in human preterm milk measured by using the MLE reporter cells. Data represent milk samples from four different mothers. B: preincubation of rTGF-β₂ with chondroitin sulfate in vitro (in phosphate-buffered saline) inhibited the biological activity of rTGF-β₂. Line diagram (means ± SE) shows TGF-β bioactivity (pM; MLE cells). C: recombinant biglycan inhibited endogenous TGF-β bioactivity in milk. When added to milk samples already treated with chondroitin sulfate, recombinant biglycan provided additional inhibition of TGF-β bioactivity. Bar diagram (means ± SE) shows TGF-β bioactivity (pM) in human preterm milk from four mothers measured by using MLE cells. **P < 0.01, ***P < 0.001.