Fig. 1
Disruption of epithelial integrity by SARS-CoV-2 WT and Omicron BA.5 can be avoided by pre-treatment with 1% P80 spray. (a) Pseudostratified epithelia were infected by apical addition of SARS-CoV-2 WT and BA.5 (MOI 0.01) with or without 1% P80 pretreatment and incubated for up to 96 h (4 dpi). Uninfected samples treated with 1% P80 were used as negative controls (UI). TEER was measured on 2 dpi (left), 3 dpi (middle) and 4 dpi (right) using an EVOM volt-ohm-meter. TEER in Ω/cm2 was determined for all conditions (UI, WT, WT + P80 1%, Omicron, Omicron + P80 1%) and plotted on a bar graph. Bars represent the mean + SD from 3 independent pseudostratified epithelia. Statistical significance was calculated using One-way ANOVA with Tukey´s multiple comparisons test. (b, c) Viral RNA (b) and plaques (c) were analyzed from subnatants of UI, WT, WT + P80 1%, Omicron, Omicron + P80 1% cultures of pseudostratified epithelia on 4 dpi. The experiment was repeated at least 3 times and statistically significant differences were determined by one-way ANOVA with Tukey´s multiple comparisons test. All values are means ± SD. Left, copy numbers are depicted, while the right panel shows plaque forming units (PFU) from 3 independent experiments (bar graph) and one representative plaque assay (images). (d) Immunofluorescence analyses of Omicron and Omicron/P80 1%-infected tissues are illustrated at a 5xAIR (upper panel) and 63xWater (lower panel) magnification. The 5x magnification shows an overview on the virus-infected tissue slides minus (left)/plus (right) 1% P80 pre-treatment, while the xyz view using the 63xW objective illustrates the tissue protection by P80 treatment (right) compared to solely infected (left) cultures. Tissues were stained using MUC5AC (Mucus, orange), SARS-CoV-2 N (SARS-CoV-2, green), acetylated tubulin (Cilia, red) and Hoechst (Nuclei, blue). (e) Percentages of SARS-CoV-2-infected HAE tissue samples using both, WT and Omicron variants (SARS-CoV-2), are depicted. At least 500 cells were quantified per condition, significant differences were determined using GraphPad Prism and one-way ANOVA