Fig. 4. Determination of phagocytic activity and dendritic differentiation potential. (A-C) BMMs, pOCs and pOCs treated with (+SP) or without (–SP) SP for 24 hours were incubated with FITC-labeled zymosan for 45 minutes as described in the Materials and Methods. After washing, cells were permeabilized and incubated with propidium iodide. (A) Cells that have taken up zymosan appear yellow because of overlap of green (FITC-zymosan) and red (propidium iodide) fluorescences in confocal microscopy when images were merged. (B) The cells were also analyzed for FITC fluorescence by flow cytometry. n.c., negative control cells incubated without FITC-zymosan and stained with FITC-Ig. The x-axes represent fluorescence intensity for FITC-zymosan-positive cells. (C) Histograms show the percentage of phagocytic cells determined by flow cytometry. Error bars represent s.d. from triplicate samples. Results are representative of three independent experiments. (D,E) BMMs, and –SP and +SP cells were stained for CD11c and F4/80 before and after culture in dendritic-differentiation medium as described in the Materials and Methods. The percentage of dendritic cells (DCs) (F4/80^–CD11c⁺) and macrophage (M) population (F4/80⁺CD11c^–) was determined by flow cytometry.