Concentration dependency of Jo2-induced growth suppression of Lin− BM progenitor cells in the absence and presence of TGF-β1 . Two thousand Lin− cells were plated in IMDM-based 1.2% methylcellulose (final concentration), and supplemented with 20% FCS, GM-CSF (20 ng/mL), and TNF-α (20 ng/mL). As indicated, cultures were incubated in the absence (▥) or presence () of TGF-β1 (20 ng/mL) and increasing concentrations of Jo2. After 7 to 9 days of incubation cultures were scored for colony formation (<50 cells). Irrelevant hamster control IgG antibody at concentrations up to 1 μg/mL had no effect on colony formation (data not shown). Results represent the mean values from four separate experiments with duplicate determinations; error bars show SEM.
