Immunoglobulin E

Commonly referred to as IgE

IgE

IgE - B. Catchpole, RVC 2008

Unlike IgM, IgG and IgA, IgE does not function as a soluble antibody and is found in low levels in blood plasma. Like IgA it is produced by plasma cells and is mainly localised to mucosal surfaces.

Structure

IgE is Y-shaped with heavy chain type ε, and exists as a monomer.

Note: Janeway states that IgE has no hinge region whereas Tizard indicates that it does.

Production

It is produced when Th2 cells stimulate CD40 and produce Il-4 and Il-13 which causes B cell differentiation to plasma cells and class switching to IgE production.

Function

• IgE triggers acute inflammation by binding to the FCεRI receptors on mast cells in the lamina propria and basophils, causing degranulation
• It is involved in type I hypersensitivity reactions
• Cross-linking of IgE molecules by antigen triggers mast cell degranulation and an inflammatory response

• IgE has considerable involvement in producing immunity to parasitic worms and particularly nematode parasites
  • It may mediate their expulsion or killing via mast cell activity, cytotoxic eosinophils, macrophages, and so on

References

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^{Immunoglobulins: Immunoglobulin A, Immunoglobulin D, Immunoglobulin E, Immunoglobulin G & Immunoglobulin M}