Fig. 1: BA.5 infection in hACE2.Tg mice results in attenuated pulmonary viral load and pathology.
From: Omicron sub-lineage BA.5 infection results in attenuated pathology in hACE2 transgenic mice
Mice were challenged with ancestral Wuhan strain (Wuhan-Hu-1), Omicron (B.1.1.529) or omicron-sub-lineage (BA.5) strain intranasally with 105 pfu virus/ mice. Clinical signs and body weight were recorded for 6 days post challenge or until they become moribund for immunopathological studies. For survival study animals were monitored till day 14 post infection. a line graph showing mean percentage changes in body mass of the mice as compared to the day 0 body mass. b Percentage survival of mice till day 14 after different challenge strains. c Representative images of harvest lungs on day 6 post infection showing regions of inflammation & pneumonitis (black arrow). d Representative H & E stained images of lung section at 40X showing pneumonitis (blue arrow), lung injury (red arrow), inflammation (black arrow). e Representative IHC images for N antigen (black arrow) in the lung sections (f) blinded scoring of IHC stain by trained pathologist on the scale of 0 to 5 (where 0 meant no stain & 5 meant highest brown color stain distribution). g Viral titer in the trachea expressed as TCID50. h Viral titer in the lungs expressed as TCID50. i longitudinal viral titer in the lungs expressed as TCID50 at day 14 and 21 post infection (j) relative mRNA expression of hACE2 gene in the mice lungs. For all experiment n = 5. One way-Anova using non-parametric Kruskal–Wallis test for multiple comparison. ns non-significant, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.
