Figure 5.
Antibody profiles are major drivers of neutrophil function
(A) Plasma SARS-CoV-2 spike (S) protein-specific IgA1 log10(MFI) values.
(B) Heatmaps displaying the signed (by FC) −log10(p) comparing levels of antigen-specific antibody isotypes between AMax1 and AMax2. Rows indicate antigens: SARS-CoV-2 (S, S1, S2, N, and receptor-binding domain [RBD]), human coronavirus OC43, influenza hemagglutinin (HA), and cytomegalovirus (CMV).
(C) Schematics for functional assays.
(D) Background-corrected antibody-dependent neutrophil phagocytosis (ADNP) assay.
(E) Log10 ratio of S-specific IgG1 to IgA1 MFI.
(F) Boxplots of background-corrected ADNP log10(MFI) values for severe patients on day 7, separated by IgG/IgA ratios.
(G) Paired-line plots of ADNP log10(MFI) values showing effects of SARS-CoV-2 S-specific IgG or IgA from day 7 plasma samples (n = 12 per condition).
(H) Reactive oxygen species luminescence of neutrophils exposed to IgG:S or IgA:S ICs or PBS. Color bars display the −log10(p) between IgG and IgA at each time point, with gray indicating no significant difference (n = 12 per condition).
(I) Representative microscopy images of neutrophil morphologies. PC, phase contrast; DAPI, DNA stain; NE, neutrophil elastase. Scale bars are indicated for each row of images.
(J) Mean percentage of cells undergoing any form of cell death quantified by fluorescence microscopy (controls n = 2 each, IgG/IgA n = 6 each).
(K) SYTOX Green Nucleic Acid Stain log10(RFU) from neutrophils exposed to free IgG or IgA (n = 12 per condition).
(L) MFI FC values of surface markers of neutrophil degranulation (controls n = 2 each, IgG/IgA n = 15 each).
p values for Wilcoxon rank-sum tests (A and L).