Figure 7: SARS-CoV-2 infection of Interleukin-2 receptor subunit gamma knockout hamsters (IL2RG^−/−) results in persistent infection and pneumonia.

IL2RG KO hamsters lacking mature B-cells, T-cells and NK cells, were infected with 5×10⁴ ID₅₀ (10^5 TCID₅₀) and followed for 24 days to determine if disease developed. Weights were collected daily and shedding from mucosal membranes and viral infectivity in the lungs were measured at the time points noted. (A) Daily weights. (B) Viral genome load recovered from oral and rectal swabs at each time point. (C) Infectious titers in the lungs. (D) Alveoli frequently contain macrophages, neutrophils and sloughed epithelial cells, and are lined by numerous hyperplastic type II pneumocytes (H&E, 200x). (E) Immunoreactivity is observed in hyperplastic type II pneumocytes and macrophages (Anti-SARS-CoV-2 nuclear protein, 200x). Note (B): blue circles, oral swabs; red circle, rectal swabs. Size bar is 100um.