D614G mutation does not alter antibody binding to either spike variant. A, Raw absorbance (optical density [OD] at 450–650 nm) values for 88 donors from a high-incidence community and 100 archival pre-2019 donors. B, Absorbance signals of D614 (original) and G614 (new dominant variant) spike proteins for immunoglobulin (Ig) G, IgM, and IgA antibody classes. C, Correlation of signal intensity of IgG after normalization of high-incidence samples to mean of archival negative controls (linear range, OD <3).