Characterization of an intratracheal aerosol challenge model of Brucella melitensis in guinea pigs
Fig 5
Histopathology of the spleen following Brucella infection.
(A) Representative images of histopathology and immunohistochemistry of the spleen following intratracheal inoculation with PBS (top), B. melitensis 16M at low dose (middle), or high dose (bottom) at 30-days post-inoculation. (B) Sections were scored for severity from 1–4 (S1 Table) based on accumulation of epithelioid macrophages, neutrophils, and necrosis. The white dashed box in the left panel indicates the section highlighted for higher magnification in the middle and right panels. Infection with B. melitensis induces accumulation of epithelioid macrophages (*). Brucella antigen was detected within epithelioid macrophages by immunohistochemistry (arrows). Magnification 4x (left, H&E, bar = 200 μm), 20x (middle, H&E, bar = 50 μm), 40x (right, Anti-Brucella IHC, bar = 20 μm).