Induction of dendritic cell differentiation in the presence of GM-CSF and its inhibition by c-Fos expression.

(A) The c-Kit⁺c-Fms⁺RANK⁻ cells were cultured in liquid medium containing M-CSF alone; or M-CSF, sRANKL, and GM-CSF; or 1.2% methylcellulose medium containing M-CSF and sRANKL for 6 days, and the expression of CD11c and Mac-1 was examined by FACS. Expression of CD11c was induced by addition of GM-CSF. (B) The c-Kit⁺c-Fms⁺RANK⁻cells were prepared from wild-type littermates (i) and Mx–c-fos mice (ii) and cultured in the presence of GM-CSF alone; GM-CSF and sRANKL; and GM-CSF, sRANKL, and IFN-α/β. After 6 days of cultivation, cells were harvested and stained with CD11c and Mac-1. The CD11c⁺Mac-1⁺ cells were induced by GM-CSF, and the CD11c⁺Mac-1⁻ cells appeared in the presence of GM-CSF and sRANKL in both wild-type littermates and Mx–c-fos mice. However, the expression of CD11c was reduced by induction of c-Fos in Mx–c-fos mice.