IgE, IgE Receptors and Anti-IgE Biologics: Protein Structures and Mechanisms of Action

The evolution of IgE in mammals added an extra layer of immune protection at body surfaces to provide a rapid and local response against antigens from the environment. The IgE immune response employs potent expulsive and inflammatory forces against local antigen provocation, at the risk of damaging host tissues and causing allergic disease. Two well-known IgE receptors, the high-affinity FceRI and low-affinity CD23, mediate the activities of IgE. Unlike other known antibody receptors, CD23 also regulates IgE expression, maintaining IgE homeostasis. This mechanism evolved by adapting the function of the complement receptor CD21. Recent insights into the dynamic character of IgE structure, its resultant capacity for allosteric modulation, and the potential for ligand-induced dissociation have revealed previously unappreciated mechanisms for regulation of IgE and IgE complexes. We describe recent research, highlighting structural studies of the IgE network of proteins to analyze the uniquely versatile activities of IgE and anti-IgE biologics.

Automated summary

The evolution of IgE in mammals provided an additional layer of immune protection at body surfaces for rapid and local response against environmental antigens. The IgE immune response includes expulsive and inflammatory forces against local antigen stimulation, but it may also cause tissue damage and allergic disease. Two well-known IgE receptors, FceRI and CD23, mediate IgE activities. Unlike other antibody receptors, CD23 also regulates IgE expression to maintain IgE homeostasis. Recent research has revealed previously unknown mechanisms for regulation of IgE and IgE complexes, such as the dynamic structure of IgE and its allosteric modulation capacity.