Depletion of macrophage population in irf8 MO^sp morphants. (A-B) WISH shows csf1r RNA expression in the yolk sac of 22 hpf control embryo (n = 42/42) and 22 hpf irf8 MO^sp morphant (n = 40/40). (C-D) WISH shows csf1r RNA expression in the CHT of 30 hpf control embryo (n = 38/38) and 30 hpf irf8 MO^sp morphant (n = 36/36). Blue arrows indicate myeloid cells whereas black arrowheads represent neural crest-derived pigment cells. (E-F) WISH shows apoeb RNA expression in the brain region of 3 dpf control (n = 45/45) and irf8 MO^sp morphant (n = 43/43) embryos. (G-H) Double staining of DsRed and GFP with antibodies shows macrophages loaded with E. coli. (red, blue arrows) and neutrophils (green) in the CHT of 40 hpf control embryo (n = 23/27) and irf8 MO^sp morphant (n = 21/22).