Extended Data Fig. 8: SARS-CoV-2 live virus neutralization.

a, HeLa cells expressing DC-SIGN are refractory to SARS-CoV-2 infection. HEK293T or HeLa cells stably expressing DC-SIGN were infected with SARS-CoV-2-Nluc at MOI 0.04 in the presence of the indicated antibodies. Infection was analyzed by quantification of luminescent signal at 24 h post infection (n=2 biologically independent replicates). b, Neutralization of infection by SARS-CoV-2-Nluc pre-incubated with the stem helix antibody S2P6 on HEK293T cell lines stably overexpressing lectins or ACE2. Infection was measured by luciferase signal 24h post infection (n = 3 biologically independent replicates) c, Infection neutralization by authentic SARS-CoV-2-Nluc pre-incubated with indicated mAbs on HEK293T cell lines stably overexpressing L-SIGN (n=3 biologically independent replicates). Infection was measured by luciferase signal 24h post infection (n = 3 biologically independent replicates). d, HEK293T cells stably expressing ACE2 or lectins were infected with SARS-CoV-2 at MOI 0.02 in the presence of the indicated mAbs. Cells were fixed 24h post infection, viral nucleocapsid protein was immunostained and positive cells were quantified (n = 3 biologically independent replicates). e, Summary of the mechanisms of action of different classes of spike-specific mAbs based on this and previous studies. *, mAb-mediated inhibition of fusion between CHO-spike cells and ACE2⁺ Vero-E6 cells; **, based on mAb-dependent activation of human FcgRs performed with a bioluminescent reporter assay as in ref. ^{25 æ}, S2X58 binds to open RBD due to a conformational clash with neighboring NTD.