Fig. 5: Preparation of GEL loaded with α-2,6 sialic acid-overexpressing MV (sMV@GEL) and its protective effect against H1N1-CA07 aerosols.

a Schematic for the preparation and H1N1 virus entrapment mechanism of MV with α-2,6 sialic acid-overexpression (sMV). b CLSM images showing SA expression on different cells. White: sialic acid (SA); Blue: nuclei. c CLSM image of CFSE stained ST-293T cells (red) after 30 min of cytochalasin B treatment. d CLSM image showing SA expression on sMV. White: SA; Red: sMV. e TEM images of ultrathin section of sMV after 24 h of challenge H1N1-CA07. The red arrow indicated H1N1-CA07. f Representative photographs of Madin-Darby canine kidney (MDCK) cells after 3 days of challenge with H1N1-CA07 under different dose of nMV or sMV protection. g Relative level of H1N1-CA07 mRNA in MDCK cells of different groups (PBS, 50 μg nMV, and 50 μg sMV). h CLSM images of sMV@GEL showing sMV were embedded in the network of gel. Cyan: GEL in sMV@GEL; Red: sMV in sMV@GEL. i Schematic diagram for evaluating the in vivo protective effect of sMV@GEL against H1N1-CA07 aerosols in mice. j Relative level of H1N1-CA07 mRNA in the nasal cavity (left) and lung (right) in the PBS group and sMV@GEL group after 7 days of challenge with low dose of H1N1-CA07 aerosols. k, l Representative IHC (upper) and H&E (lower) sections of the nasal cavity (k) and lung (l) in PBS group (left) and sMV@GEL group (right) of j. The red arrows: N protein of H1N1-CA07 (brown). m Schematic of H1N1-CA07 transmission model. n Relative level of H1N1-CA07 mRNA in the IR nasal cavity (left) and lung (right) after 3 days exposed to donor. o Number of infected TR in each cage after 3 days exposed to PBS IR (left) or sMV@GEL IR (right). Data in g, j and n represent as means ± S.E.M., n = 3 biologically independent experiments (g), n = 6 biologically independent mice (j, n). Statistical significance was tested with two-tailed unpaired t-test (j, n) and one-way ANOVA with multiple comparison tests (g). All significant P-values are indicated. Source data are provided in the Source data file.