IL-6–induced macrophage-differentiation of 1A9-M cells. (A) 1A9-M cells were cultured with (right panel) or without (left panel) 20 ng/mL IL-6 for 48 hours. The cells were prepared by cytospin, stained by May-Grunwald-Giemsa, and photographed at 1,000× magnification. (B) 1A9-M cells were cultured with or without 20 ng/mL IL-6 for 24 hours. Surface expression of CD32/CD16 and a F4/80 antigen was evaluated by flow cytometry.