Figure 8.

Tissue macrophages interact with endothelial cells at sites of vessel fusion in the developing zebrafish trunk. Series of laser confocal projections extracted from a time-lapse video (supplemental Video 1) showing the interaction of 3 tissue macrophages (red; 1-3) with blood vessels (green); the time elapsed after starting the video at 28 hpf is indicated in hours:minutes in the bottom left of each panel; 3 adjacent intersegmental blood vessels are imaged over a period of 4:16. (A) A macrophage (1) migrates into a region where the tip cell from the caudal sprout of one intersomitic vessel fuses with the tip cell of a rostral sprout of the next intersomitic vessel; arrows indicate the direction of macrophage migration. (B) A macrophage (2) migrates to a site where a dividing endothelial cell in the forming DLAV (clear arrowhead) transiently loses contact with the intersomitic vessel (arrowheads); it remains in this position while the connection is re-established (forked arrowheads); yet another macrophage (3) interacts with filopodial protrusions from opposing tip cells (wavy arrow). Scale bar represents 50 μm.