For Western blot assay, infected Vero E6 cells were collected and lysed at 72 h post-infection with the recombinant viruses at an MOI = 1. Samples were electrophoresed in SDS-10% polyacrylamide gels, and the proteins were transferred onto nitrocellulose membranes. Western blot detection was performed with mouse anti-S serum at a dilution of 1:1000 (Invitrogen, Oregon, USA) and HRP-labeled goat anti-mouse IgG at a dilution of 1:3000 (Genscript, Nanjing, China). The bands were visualized with Azure C300–C500 (Cycloud, Beijing, China).
For indirect immunofluorescence assay, Vero E6 cells were planted onto 24-well plates and infected with the recombinant viruses at an MOI = 1. At 36 h post-infection, the infected cells were fixed and subjected to indirect immunofluorescence with mouse anti-S serum as the primary antibody at a dilution of 1:100 (Invitrogen, Oregon, USA), and Alexa Fluor 568-conjugated goat anti-mouse IgG as the secondary antibody at a dilution of 1:2000 (Invitrogen, Oregon, USA). Cell nuclei were stained with Hoechst 33342 (Invitrogen, Oregon, USA). The Staining cells were analyzed with LSM880-ZEISS confocal laser scanning microscopy with fast Airyscan (Carl Zeiss, Germany).
For indirect immunofluorescence assay, Vero E6 cells were planted onto 24-well plates and infected with the recombinant viruses at an MOI = 1. At 36 h post-infection, the infected cells were fixed and subjected to indirect immunofluorescence with mouse anti-S serum as the primary antibody at a dilution of 1:100 (Invitrogen, Oregon, USA), and Alexa Fluor 568-conjugated goat anti-mouse IgG as the secondary antibody at a dilution of 1:2000 (Invitrogen, Oregon, USA). Cell nuclei were stained with Hoechst 33342 (Invitrogen, Oregon, USA). The Staining cells were analyzed with LSM880-ZEISS confocal laser scanning microscopy with fast Airyscan (Carl Zeiss, Germany).