Neutrophil development in WHIM-GFP larvae. (A-F) Sudan Black staining in the CHT of wild-type (WT) (A,C,E) or WHIM-GFP (B,D,F) larvae at 3 (A,B), 7 (C,D), and 13 (E,F) dpf. Lateral view, anterior to the left. Arrows point to neutrophils over the gut (C) or in clumps in the CHT (B,D,F). Arrowheads point to neutrophils along the dorsal ridge (C) or midline (F). (G-L) Lateral view (G,I,K) or ventral view (H,J,L) of the head of WT (G-J) or WHIM-GFP (K,L) 3-dpf larvae stained with Sudan Black (G,H,K,L) or for SDF1a expression (I,J) by WISH. Arrows point to area of dark SDF1a expression (I,J) or areas of neutrophil accumulation (K,L) on the ventral side of the head under the jaw. (M-P) Sudan Black staining to show neutrophils in the kidney (arrows) in 7 (M-N) and 13 (O-P) dpf WT (M,O) or WHIM-GFP (N,P) larvae. Lateral view, g indicates gut. Bar = 200 μm (A-P).