a, Fold increase or decrease in IC50 of neutralizing monoclonal antibodies against B.1.1.7, B.1.351, B.1.1.7Δ8, B.1.351Δ9 and single-mutation pseudoviruses relative to the wild-type (WT) virus, presented as a heat map in which darker colours indicate a greater change. MPI with a downward arrow indicates that the maximum percentage inhibition is substantially reduced, confounding IC50 calculations. Red, resistance >3-fold; green, sensitization >3-fold. b, Neutralization of B.1.1.7, B.1.351 and wild-type viruses by NTD-directed monoclonal antibodies, the footprints of which are delineated by the colour tracings in the inset. The horizontal dotted lines on each graph indicate 50% and 0% neutralization. Data are mean ± s.e.m. of technical triplicates and represent one of two independent experiments. c, Changes in neutralization IC50 of authorized or investigational therapeutic monoclonal antibodies against B.1.1.7, B.1.351 and wild-type (WA1) viruses (left) as well as B.1.1.7Δ8, B.1.351Δ9 and wild-type (D614G) pseudoviruses (right).