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Fig. 7
Virulence of ΔMAB_4780 is attenuated in a neutrophil-depleted host. (A) Maximum intensity projection of confocal images showing representative neutrophil activity (at 2 dpi) in pu.1 Tg(mpx:egpf) morphants i.v.-infected with Mabs R, ΔMAB_4780, or complemented strain expressing tdTomato. (B) Csf3r Tg(mpx:egpf) morphants showed highly reduced neutrophil numbers at 3 and 4 dpf, confirming the proper activity of the morpholino. The numbers of mpx-positive neutrophils counted in the trunk and tail at 3 dpf are depicted in the graph. (C) Survival curve of neutrophil-depleted larvae i.v.-infected with the Mabs R, ΔMAB_4780, and complemented strains (~150 cfu, n = 20 per group). These larvae were hypersusceptible to Mabs R and to the complemented strain (P < 0.001, log-rank test) but not to ΔMAB_4780 (statistically not different from PBS-injected controls). Shown are representative data from two independent experiments. (D) Representative fluorescence and DIC overlays of infected csf3r morphants at 2 and 3 dpi.