Fig. 5. The IV formulation provides enhanced protection in mice compared to the S formulation, indicating ameliorated lung pathology, reduced viral titers and expression of virus antigens in the lungs of mice with IV or S.

Representative results of hematoxylin-eosin (HE) staining (×400) in the lungs of mock-treated or immunized mice (a). Immunohistochemistry staining (×400) with anti-S and anti-NP mAbs (b). Lung virus titers 3 days after MERS-CoV challenge (c) as detected by virus isolation and titration at day 3 post-challenge. Values are the means ± SEM. Significant values are defined by ***P < 0.001