Cell cycle and surface phenotype of skin-derived mast cells.

(A) Relative DNA content of skin-derived mast cells after about 4 weeks of culture in AIM-V media. Cells were incubated with 50 μg/mL PI for 10 minutes on ice just before (7 days after last rhuSCF feeding, left panel) and 24 hours (right panel) after a rhuSCF feeding, and analyzed by flow cytometry. (B) Surface Kit⁺ mast cells 1 day after their initial dispersion (left panel) and 7 days after rhuSCF feeding of cells grown in AIM-V suspension culture for 6 weeks (right panel). (C) FcεRI surface expression of Kit⁺ cells 1 day after their initial dispersion (left panel) and 7 days after rhuSCF feeding of cells grown in AIM-V suspension culture for 6 weeks (right panel). Shaded areas in panels B and C show anti-FcεRI and anti-Kit labeling, respectively; bold lines indicate negative IgG controls. Each panel is representative of 3 separate experiments.