Figure 4.

Histopathological analysis of aortic valves in comparison to the five experimental groups 24 h post induction of IE: naïve controls, sham-operated mice and mice infected with S. aureus isolates 17, 30 or 33 in the IE model. Hematoxylin-eosin staining (a; left column: ×4 magnification; middle column: ×10 magnification) and Gram staining (a; right column: ×10 magnification) showing massive immune cell infiltration. Immunofluorescence staining using CD45 as pan-leukocyte marker (b, red fluorescence, left column: ×10 magnification) and F4/80 as mouse macrophage marker (b, red fluorescence, right column: ×10 magnification) in representative tissue samples of the aortic valve. Blue fluorescence represents DAPI nucleic acid staining. The scale bars in the images illustrate 100 µm