Figure 6. Histopathological analysis and viral antigen detection in the lung.

Seven or 10 days after challenge, lungs were harvested, and multiple sections of lung were evaluated histologically and immunohistochemically for the presence of SARS-CoV-2–related inflammation and SARS-CoV-2 virus antigen. Representative images were from lungs harvested day 7 from 1 animal in the naive group (A) and 1 animal in vaccinated group 1 (B). Each animal was blindly scored by a pathologist based on the degree of inflammation in the lung. In the box and whiskers plot, the median, other quartiles, and minimum and maximum are shown. Mann-Whitney U tests corrected for multiple comparisons by the Hochberg method were used to compare the lung inflammation between SARS-CoV-2 naive control and vaccination groups (C). Scale bars: 200 μm (original magnification, ×4) and 100 μm (original magnification, ×10). n = 6 for groups 1 and 2 and naive group.