Fig 2. CV804 binds to SARS-CoV-2 and its variants, but does not neutralize them.

(A) Five humanized CV804 antibodies were analyzed by flow cytometric assay of titrated candidates against SARS-CoV-2 spike protein expressing cells. Four parameter logistic curve fitted with EC₅₀ in parentheses. Normalized by secondary alone and saturation signal. Representative data of two independent experiments are shown. (B) Evaluation of hCV804-40 antibody, REGN10987, and LY-CoV1404 antibody binding to cells infected with SARS-CoV-2 variants. "+++", "++", "+" indicate positive binding; "-" indicates negative binding. (C) Evaluation of antibody-dependent cell-mediated cytotoxicity ADCC activity against spike-expressing cells for mouse derived antibodies. (D) In vitro cell infection inhibition experiments were conducted. The viral strains used were hCoV-19/Japan/TY/WK-521/2020 (top) and SARS-CoV-2/Japan/TY-501/2020 (bottom), with VeroE6/TMPRSS2 cells being used as the target cells. The hCV804-35 antibody, REGN10987, and LY-CoV 1404 were measured in this experiment. The antibody concentration that inhibited cell death by 50% was defined as the IC₅₀.