Extended Data Fig. 5: Removal of sialic acid from IgE.
From: Sialylation of immunoglobulin E is a determinant of allergic pathogenicity
a, Protein gel stain and lectin blots of IVIG, native human IgE purified from patients with allergies, and fetuin. MALI, Maackia amurensis lectin I. b, HPLC glycan traces of undigested (Utx) allergic hIgE and fetuin; of allergic hIgE and fetuin digested with sialidase from A. ureafaciens to release α2,3-, α2,6-, α2,8- and α2,9-linked sialic acids (α2-3, 6, 8, 9 NEU-tx); and allergic hIgE and fetuin digested with sialidase from Streptococcus pneumoniae to release α2,3-linked sialic acids (α2-3 NEU-tx). c, HPLC glycan traces of undigested or recombinant OVA-specific mIgE digested with sialidase from A. ureafaciens. d, Left, quantification of vascular leakage by Evan’s blue dye (n = 6 mouse ears per group) after PCA in mice sensitized with PBS or with SiamIgE or AsmIgE specific for DNP; right, representative ear images. e, Gating strategy for IgE loading on mouse skin ear mast cells. Shown are representative FACS plots used to identify mast cells in mouse ears and to determine IgE levels on mouse ear mast cells. SSC, side scatter. f, Binding of OVA-specific SiamIgE and AsmIgE to OVA, as determined by ELISA. n = 2 technical replicates per group, representative of three biologically independent experiments. g, h, OVA-elicited systemic anaphylaxis as measured by temperature drop in mice sensitized with PBS, OVA-specific SiamIgE (g, n = 4; h, n = 6) or OVA-specific AsmIgE (g, n = 5; h, n = 6) by intravenous (g) or intraperitoneal (h) injection. i, Serum levels of DNP-specific SiamIgE (n = 4) and AsmIgE (n = 3) in mice at defined times after systemic administration, determined by ELISA. Data are means ± s.e.m. and are representative of three experiments. P values determined by two-tailed paired t-test (d) or two-way ANOVA with Tukey’s multiple comparison test (g, h).
