Receptors for IgE

There are two cell surface receptors for IgE: FceRI and FceRII (also known as CD23). Their properties are set out in Table 2.

FceRI comprises four polypeptide chains: one a, one (3 and two y chains (Table 2). Only the first possesses an appreciable length of extracellular sequence; this contains two immunoglobulin-like domains and can be modelled on the nuclear mag-

Figure 2 IgE adopts a bent conformation in solution. The immunoglobulin domains of IgE are represented by ellipses, and are arranged in a conformation compatible with available structural data. Also indicated is the measurement between the ends of the molecules as determined by fluorescence energy transfer methods; the diagram is to scale.

Figure 2 IgE adopts a bent conformation in solution. The immunoglobulin domains of IgE are represented by ellipses, and are arranged in a conformation compatible with available structural data. Also indicated is the measurement between the ends of the molecules as determined by fluorescence energy transfer methods; the diagram is to scale.

netic resonance and crystal structures of two homologous proteins (CD4 and CD2). It is known to form the binding site for IgE. The other three chains have more extensive intracellular sequences and are responsible for signal transduction. The affinity of FceRI for IgE (KA ~ lO^M"1) is at least 1-2 orders of magnitude higher than that of any other Fc receptor-antibody interaction. FceRI forms a 1:1 complex with IgE, attaching to one or both of the Q3 domains. Ce4 sequences, however, are required for binding with full high affinity, probably because of their influence on the structure or disposition of the Ce3 domains. The activities of FceRI are a function of the cells in which it is expressed, and include IgE antibody-dependent antigen presentation in Langer-

How To Bolster Your Immune System

How To Bolster Your Immune System

All Natural Immune Boosters Proven To Fight Infection, Disease And More. Discover A Natural, Safe Effective Way To Boost Your Immune System Using Ingredients From Your Kitchen Cupboard. The only common sense, no holds barred guide to hit the market today no gimmicks, no pills, just old fashioned common sense remedies to cure colds, influenza, viral infections and more.

Get My Free Audio Book


Post a comment