Fig. 4: Distribution of aMV@GEL after intranasal administration and its in vivo protective effect against SPV aerosols.

a Schematic diagram for evaluating the distribution of free aMV and aMV@GEL after intranasal administration. b Representative in vivo fluorescence images of mice at the indicated time points after intranasal administration of free aMV or aMV@GEL. aMV in both groups were stained with Cy5. c Relative fluorescence intensity (F.I.) of free aMV or aMV@GEL in mouse nasal cavity in b (left) and corresponding half-life (right). d Representative frozen section images and enlarged views of the mouse nasal cavity at 8 h after intranasal administration of free aMV or aMV@GEL. Red: Cy5 stained aMV; Blue: DAPI stained cell nuclei. e Representative ex vivo fluorescence images of various tissues (nasal cavity, brain, lung, heart, liver, spleen, and kidney) at 8 h after intranasal administration of free aMV or aMV@GEL. aMV in both groups were stained with Cy5. f Schematic diagram for evaluating the in vivo protective effect of aMV@GEL against SPV aerosols. g Representative frozen section images and enlarged views of mouse nasal cavity (left) and relative level of GFP mRNA in the nasal cavity by using q-PCR detection (right) after 3 days of challenge with SPV (wild-type) aerosols. GFP was produced by SPV-infected cells; Blue: DAPI stained cell nuclei. h Representative frozen section images and enlarged views of mouse lung (left) and relative level of GFP mRNA in the lung tissue by using q-PCR detection (right) after 3 days of challenge with SPV (wild-type) aerosols. GFP was produced by SPV-infected cells; Blue: DAPI stained cell nuclei. i Relative level of GFP mRNA that was produced by SPV-infected cell in nasal cavity and lung using q-PCR detection after 3 days of challenge with SPV (S protein B.1.1.529 mutation (Omicron)) aerosols. Quantitative data in c, g, h, and i represent as means ± S.E.M., n = 3 biologically independent mice. Statistical significance was calculated using two-tailed unpaired t-test (c, i) and one-way ANOVA with multiple comparison tests (g, h). All significant P-values are indicated. Source data are provided in the Source data file.