Fig. 11.

Mice (n=4–6 mice per group/time point) were injected with either S. aureus strain RN6390- or S. aureus strain Reynolds-beads (10⁴CFU) as described in the Materials and methods. Animals were euthanized at the indicated time points, whereupon brain tissues were flash frozen on dry ice for subsequent cryostat sectioning. Serial 10 μm thick sections were prepared throughout the entire abscess, subjected to immunofluorescence staining for tryptase (red), and imaged by confocal microscopy (magnification 63×). Nuclei were visualized using Hoechst 33342 (blue). Tryptase immunoreactivity was prominent at day 7 in the abscess area. Results are representative of two independent experiments.