B Vero E6 cells were inoculated with SARS-CoV-2, fixed with paraformaldehyde after two days, stained with 30 nM of the indicated Alexa Fluor 488 (AF488)-labeled anti-RBD VHH antibodies, and imaged by confocal laser scanning microscopy (CLSM). C Immunofluorescence (IF) staining as in B, but with the indicated AF568-labeled anti-S1ΔRBD VHH antibodies. 