Panel A: Line graphs showing ELISA binding curves of I g D r m A b s and control antibodies to environmental antigens. Panel B: Heatmap showing binding intensity of I g G r m A b s from M E B cells across multiple antigens. Panel C: Flow cytometry histograms showing binding of I g D r m A b s from I g D-M E B cells to bacterial isolates. Panel D: Heatmap showing percentage of bacterial binding by I g D r m A b s from I g D-G C B cells. Panel E: Flow cytometry histograms showing bacterial binding of I g D r m A b s and control antibodies from I g D-G C B cells. Panel F: Sequence alignment showing I G H V gene usage in wild type and germline I g D monoclonal antibodies. Panel G: Violin plots showing reactivity of circulating I g D polyclonal antibodies (p A b s) to various antigens across patient groups. Panel H: Line graphs showing reactivity curves of circulating I g E polyclonal antibodies (p A b s) in H I E S patients.
IgD antibodies recognize environmental, commensal, and autologous antigens. (A) ELISA-determined binding curves of 23 IgD rmAbs from tonsillar IgD-GC B cells (red) and 10 control (blue) rmAbs from circulating ME B cells to birch pollen (Bet v 1) and whole casein. Control rmAbs were isolated from ME B cells purified from the peripheral blood of SARS-CoV-2 patients. Dashed lines, reactivity thresholds. (B) Heatmap summarizing binding intensity of IgG rmAbs (10 μg/ml) from tonsillar IgG-ME B cells to antigens as in Fig. 7 B. (C) Flow cytometry showing binding of IgD rmAbs from IgD-ME B cells to isolated bacterial strains. 2ry ab, secondary antibody alone; ctrl rmAbs, control rmAbs. (D) Heatmap summarizing the percentage of selected bacterial isolates bound by IgD rmAbs from IgD-GC B cells determined as in Fig. 7 C. (E) Flow cytometry showing binding of IgD rmAbs from IgD-GC B cells or ctrl rmAbs to isolated bacterial strains as in D. (F) IGHV4-34 and IGHV3-30 gene sequences from mutated wild-type (WT) mAbs 47 and 48, respectively, and their GL counterparts. Dashes represent missing GL nucleotides. (G) Violin plots representing reactivity to ovalbumin, ⍺-s-casein, and ssDNA by circulating IgD pAbs from HCs, HIDS patients, and HIES patients. (H) Reactivity curves of circulating IgE pAbs from HIES patients. Symbols indicate distinct HIES-inducing mutations. Data are from one experiment with multiple biological replicates (A–E, G, and H). Significance was determined by the Kruskal–Wallis test (G). *P < 0.05 and **P < 0.01. GL, germline.