Fig. 6

Macrophages, but not neutrophils, contribute to increased bacterial burden and pro-inflammatory responses towards subcutaneously introduced B. cenocepacia.

(A) Mpeg1/umn⁺ embryos were subcutaneously injected with B. cenocepacia K56-2 expressing Turquoise. Fluorescent overlay images were taken at 90 min and 5 h post infection, showing infected macrophages (red). Scale bars, 10 μm. (B) Images (red and blue overlay and below slightly enlarged individual fluorescence images with blue filter) of the indicated area (see drawing) of an mpx/umn⁺ (B1) and an mpeg1/umn⁺ (B2) embryo subcutaneously injected with B. cenocepacia K56-2 expressing Turquoise. B1 shows an embryo followed in time displaying neutrophil infiltration (red) and increase in bacterial burden (blue, see Fig 7A for quantification). B2 shows the image of an embryo with macrophage infiltration (red) and high bacterial burden at 24 hpi. Arrow head points at mCherry positive debris. See non-infected mpx/umn⁺ and mpeg1/umn⁺ control embryos in S6 Fig for comparison. Scale bars, 100 μm. (C) Image of the infected area of a representative mpx/umn⁺ embryo depleted of neutrophils with Mtz, and subcutaneously injected with B. cenocepacia K56-2 (Turquoise) at 24 hpi. Scale bar 100 μm, and 50 μm for inset. See also S6D Fig. (D) Image of a representative mpeg1/umn⁺ embryo depleted of macrophages with Mtz and subcutaneously injected with B. cenocepacia K56-2 (Turquoise) at 24 hpi. Scale bar 100 μm, and 50 μm for inset.