Ab150187

For immunostaining, organoids were recovered from Matrigel and then fixed in 4% paraformaldehyde overnight. The fixed organoids were then treated with 0.3% Triton X‐100 for 30 min. After washing with 1 × PBS 3 times, the organoids were blocked by 5% BSA at 37 °C for 1.5 h. To mark taste receptors in the organoid, rabbit anti‐OTOP1 (Antibodies‐online, ABIN7075125) and pig anti‐TAS1R2 (NOVUS, NBP2‐80499) were used as primary antibodies, while goat anti‐rabbit IgG (Abcam, ab150077) and goat anti‐pig IgG (Abcam, ab150187) were used as secondary antibodies, respectively. All primary antibodies were diluted 300 times and all secondary antibodies were diluted 500 times. Both stainings using primary antibodies and secondary antibodies were followed by washing with 1 × PBS 3 times. The nucleus was stained using a DAPI solution (Solarbio). An Olympus FV3000 confocal microscope was used to acquire images.

BHK-21 cells and CHO cell lines on glass-bottom cell culture dishes (20 mm, NEST) were inoculated with the sample preparations of the specific viruses at a multiplicity of infection (MOI) of 10 for 1 h adsorption at 4 °C. The virus suspensions were then removed and the inoculated cells were washed with ice-cold PBS and incubated in fresh medium at 37 °C. At the appropriate times, cells were fixed with 4% paraformaldehyde, permeabilized with 0.1% Tween 20 in PBS and blocked with 1% bovine serum albumin. After washing three times with PBS, the fixed cells were incubated with guinea pig anti-FMDV (serotype O) polyclonal antibody (1:300; CNFMDRL, Lanzhou, China), and clathrin heavy chain monoclonal antibody (1:1000, Thermo Fisher Scientific) or caveolin-1 polyclonal rabbit antibody (1:400, Thermo Fisher Scientific) overnight at 4 °C. The cells were washed again with PBS and incubated with the goat anti-guinea pig IgG H&L (ab150187, Abcam), and goat anti-mouse IgG H&L (ab6785, Abcam) or goat anti-rabbit IgG H&L (ab6939, Abcam) for 1 h at 37 °C. Following immunofluorescence, the antibody-incubated cells were washed with PBS, nuclei-stained with DAPI (1:10,000, Beyotime) for 5 min at room temperature, then washed, mounted and viewed under a Leica TCS SP8 confocal microscope. The images were captured digitally and processed by using Adobe Photoshop software.