TGF-β1 dose-dependently inhibited the generation of CD11b^−/dullCD11c⁺ and CD11b^+hiCD11c⁺ DC precursors at day 6 from murine Lin⁻c-kit⁺ HPCs stimulated with GM-CSF + SCF + TNF. (A) The percentage of CD11b^−/dullCD11c⁺ and CD11b^+hiCD11c⁺ DC precursors. (B) The absolute numbers of CD11b^−/dullCD11c⁺ and CD11b^+hiCD11c⁺DC precursors. The data represent the mean value ± SD of the percentage and numbers of the two DC precursor subpopulations observed in more than five experiments. *P < .05 significance as compared with those cultures in the absence of TGF-β1.