IMMUNOLOGY

Detailed explanation-1: -The low-affinity IgE receptor, FcRII (CD23), is a Ca-dependent lectin that is expressed on B cells, as well as T cells, Langerhan cells, macrophage, monocytes, eosinophils, and platelets.

Detailed explanation-2: -Allergen-specific TH2 cells produce IL-4 and IL-13, which drive allergen-specific B cells to produce IgE. The specific IgE produced in response to the allergen binds to the high-affinity receptor for IgE on mast cells, basophils, and activated eosinophils.

Detailed explanation-3: -IgE binds to two types of Fc receptors, called Fc epsilon R1 (or high-affinity Fc epsilon R) and Fc epsilon R2 (or low-affinity Fc epsilon R). The Fc epsilon R1 is composed of four polypeptide chains, one alpha, one beta, and two gamma chains.

Detailed explanation-4: -The role of IgE in the activation of inflammatory cells is well established, but the potential roles of IgG in asthma have not been extensively examined. IgE can bind to both high-affinity IgE-Fc receptors (FcRI) on mast cells and basophils and low-affinity receptors (CD23) on monocytes and B-cells (2).