IL8-dependent recruited neutrophils phagocytize Mabs at initial sites of infection.
(A) qRT-PCR measurement of il8 transcripts during Mabs R- or S-infections (≈150 CFU) in whole embryos at 2 and 5dpi. Mean log10 ± SEM of three independent experiments. (B) WT or il8 morphants Tg(mpx:eGFP) embryos were infected into the muscle (left), the hindbrain (middle) or the otic vesicle (right) with ≈100 R or S Mabs. Number of recruited neutrophils in injection sites at 3 hpi (two independent experiments, horizontal lines indicate the median values). (C) Microscopy showing representative neutrophil recruitment to R-abscesses in the brains of WT versus il8 morphants Tg(mpx:eGFP) larvae at 5 dpi. Scale bar, 100 μm. (D and E) WT or il8 morphants were iv infected with either R or S (tdTomato, ≈150 CFU). (D) Survival of R-(left) or S-infected (right) embryos (n = 50–60, average of two independent experiments). (E) Representative images of infected larvae at 3 dpi. Scale bars, 200 μm. (F and G) WT or csf3r morphants were iv infected with either R or S expressing tdTomato (≈150 CFU). (G) Survival of R-(left) or S-infected (right) embryos (n = 50–60, two independent experiments). (H) Representative images of infected larvae at 3 dpi. Scale bars, 200 μm. Statistical significance was determined by Kruskal-Wallis test with Dunns post-test (A), one-tailed unpaired Student’s t test (B) or by log-rank test (D and F).