Figure 5.

Histopathology following SARS-CoV-2 challenge of SARS-CoV-2 SAM (LNP) and mock vaccinated hamsters

(A) Lung pathology grading, with respect to inflammation (A) and centriacinar/bronchioloalveolar epithelial hyperplasia (B) in male and female hamsters necropsied at 3, 7, and 21 dpi with SARS-CoV-2 virus. (C) Representative lung sections from a naive male hamster showing the background level of atelectasis that can occur during necropsy. (D) Representative lung sections from mock vaccinated, SAM low dose (0.03μg), and SAM high dose (3μg) vaccinated male animals infected with SARS-CoV-2 virus and necropsied at 3, 7, and 21 dpi (histopathological features in females are consistent with those in males, females not shown). Sections are stained with H&E, and whole slide images were obtained using P250 scanner (3D Histech). Representative low-power (bottom left, scale bar 5 mm), medium-power (top, scale bar 200 μm), and higher power (bottom right, scale bar 50 μm) photomicrographs are shown from each group. “#,” hyperplasia of type II pneumocytes and bronchiolization of alveoli; “G,” hyperplasia of goblet cells within bronchial epithelium; “H,” areas of alveolar wall necrosis and hemorrhage within regions of inflammation. Further description of the histopathology at each time point is provided in the main text.