Fig. 5

Increased phagocytosis of mgtC mutant by neutrophils upon subcutaneous injection of zebrafish embryos.

(A) Survival of embryos subcutaneously injected at 3 dpf with approximately 50–100 CFU of wild-type M. marinum, mgtC mutant, complemented strain or PBS as control (n = 24). Results are from a representative experiment (infection with 119 CFU for wild-type, 74 CFU for mgtC mutant and 32 CFU for complemented strain) out of three independent experiments. A drawing of the injection site is shown. (B) Maximum intensity projection of neutrophil-phagocytosed bacteria at the site of injection, at 4 hpi by confocal microscopy. (C) Quantification of bacterial phagocytosis by neutrophils. The number of neutrophils containing phagocytosed bacteria at the site of injection was counted at 4 hpi using confocal microscope of a minimum of 10 embryos. Results are expressed+SD from a representative (104 CFU for wild-type, 82 CFU for mgtC mutant and 34 CFU for complemented strain) of three independent experiments. Asterisk indicates statistical significance (* P<0.05).