Fig. 4.

An inhibitor of ALK5 reverses the effect of transforming growth factor (TGF)-β1. Neutrophils were incubated for 15 min with (a) dimethylsulphoxide or (b) 1 µM SB431542. Medium or TGF-β1 at 1 or 10 pg/ml was then added and the cells cultured for a further 45 min. They were then challenged with lipopolysaccharide and supernatants harvested for lactoferrin determination after 2 h. Results are representative of three separately conducted experiments. Differences between cultures with and without TGF were analysed by paired t-test: *P < 0·05; **P < 0·01; ***P < 0·001.