Expression of F4/80 and α_V integrin on central macrophages. Central macrophages isolated from erythroblastic islands were analyzed by immunofluorescence microscopy in double antibody label experiments using macrophage-specific probe antibody F4/80 (green), anti-CD51 (red), and DNA (Hoechst 33342; blue). Two representative cells are shown, one in the top 3 panels and the other in the bottom 3 panels. Merged image signals showed colocalization (yellow) of the 2 antibody markers indicating that central macrophages isolated from erythroblastic islands express the α_V integrin subunit. Bar represents 10 μm.