Figure 5.
Vaccination with the indicated inactivated SARS-CoV-2 strains confers protection to infection of hamster lungs with SARS-CoV-2 Alpha variant. (A) Virus challenge scheme. Vaccinated hamsters were intranasally inoculated with 105 PFU (in 50μl) of SARS-CoV-2 Alpha variant. At 4 dpi (i.e. 33 days after vaccination), viral titers in hamster nasal wash were quantitated by RT-qPCR, whereas tracheal and lung samples were analysed by RT-qPCR (B). Broken lines in bar plots indicate detection limit. (C) Proinflammatory cytokine and chemokine gene expression in Alpha-infected hamsters. Transcripts of representative chemokines and cytokines in the lung tissue homogenates of the indicated groups were quantitated by RT-qPCR. Results are shown as means ± SEM. Statistical analysis was performed by Student's t test (n.s.: not significant; *: P < 0.05; **: P < 0.01; ***: P < 0.001). (D) Impact of vaccination on histopathological changes in lungs of SARS-CoV-2 Alpha variant-infected hamsters. Lung histopathological changes of each vaccinated hamster group at 4 dpi. Representative lung tissue sections were stained with hematoxylin and eosin. Bar, 200 μm. (E) Pathological changes in Alpha-infected lungs from the indicated vaccinated groups (**: P < 0.01).