Skip to main content
. Author manuscript; available in PMC: 2017 Jun 1.
Published in final edited form as: J Allergy Clin Immunol. 2016 Jun;137(6):1631–1645. doi: 10.1016/j.jaci.2016.04.009

FIG 2.

FIG 2

Structures of the mature ε-heavy chain gene and IgE protein. The ε-heavy chain gene generated in the IgH locus through deletional CSR (Fig 1) contains a VDJ cassette encoding the heavy chain variable regions juxtaposed to the Cε exons encoding the constant domains. A hybrid Sµ/Sε sequence remains between the VH and Cε exons, a by product of the isotype-switching process. The secreted IgE protein has 4 constant regions, 1 more of these domains than IgG. Intrachain disulfide bonds are contained within each of the immunoglobulin domains. IgE molecules are heavily glycosylated (7 N-linked sites as indicated by ovals). The N394 oligosaccharide is essential for IgE-FcεRI binding. The transmembrane form of IgE, which contains M1 and M2 exons encoded by ε-mRNA splice isoforms, is expressed at the surface of IgE+ B cells.