Fig 2: Infection of the olfactory mucosa by SARS-CoV-2, related to Figure 5Confocal images of sections through the olfactory mucosa of COVID #8 (A and B), COVID #7 (C-H), COVID #57 (I), and COVID #25 (J). (A and B) SARS-CoV-2-N puncta occur throughout the apical-basal width of the olfactory epithelium. KRT8-IR signal labels a patch of uninfected sustentacular cells (stippled line) and cells lining gland ducts in the lamina propria (A). Infected sustentacular cells are low on or negative for UGT2A1 puncta and ERMN-IR signal, in contrast to uninfected sustentacular cells (B). (C-E) SARS-CoV-2-N puncta occur throughout the apical layer of sustentacular cells, in a mutually exclusive manner with CNGA2 puncta and TUBB3-IR signal (C and D) or GNAL puncta (E) in the middle layer of OSNs. (F) Sustentacular cells harbor SOX2 puncta across their apical-basal width. The stippled lines outline two sustentacular cells harboring perinuclear SARS-CoV-2-orf1ab-sense puncta reflecting ongoing viral replication. (G and H) Three infected sustentacular cells harbor densely packed SARS-CoV-2-N puncta, reflecting a high viral load. The stippled lines in H outline two sustentacular cells that are in the plane of focus of this confocal image: their KRT18-IR signal is depleted, in contrast to the strong KRT18-IR signal in nearby uninfected sustentacular cells. (I) Remnants of TUBB3-IR OSNs do not contain nucleocapsid-IR signal. (J) A patch of disintegrating olfactory epithelium containing nucleocapsid-IR signal is flanked by two areas of olfactory epithelium that do not contain nucleocapsid-IR signal but contain numerous TUBB3-IR OSNs.