Extended Data Fig. 7: Viral genome load in upper (URT) and lower (LRT) respiratory tract tissue of ferrets in the competitive transmission experiment between SARS-CoV-2 Alpha and wt-S614G.
From: Enhanced fitness of SARS-CoV-2 variant of concern Alpha but not Beta
(a) Absolute quantification was performed by RT–qPCR analysis of tissue homogenates of donor, contact I and contact II ferrets in relation to a set of defined standards. Tissue samples were collected at euthanasia (Euth.). Pie chart colors illustrate the ratio of variants detected in each sample at the indicated dpi or dpc. Pie chart sizes are proportional to the total viral genome copies reported below. Grey pies indicate values below the LOD (<103 viral genome copies per sample). (b–e) Representative micrographs of hematoxylin and eosin staining of 3 μm sections of nasal conchae of donor ferrets (n = 6) 6 dpi with wt-S614G and Alpha. Micrographs are representative of 5 consecutive tissue samples of each animal. Insets show immunohistochemistry staining of SARS-CoV-2 with anti-SARS nucleocapsid antibody with hematoxylin counterstain. The respiratory (b, c) and olfactory (d, e) nasal mucosa exhibited rhinitis with varying severity. Lesion-associated antigen was found in ciliated cells of the respiratory epithelium (b, c) and in sustentacular cells of the olfactory epithelium (d, e) in all donor animals (n = 6) at 6 dpi. Scale bars are 100 μm.
