Immunoglobulin E Fc region (IgE-Fc)

The **Immunoglobulin E Fc region (IgE-Fc)** is the constant portion of the IgE antibody comprising the Cε2, Cε3, and Cε4 domains, and is responsible for binding to high-affinity (FcεRI) and low-affinity (FcεRII/CD23) receptors on immune effector cells[1][3][4][5]. Interaction of IgE-Fc with FcεRI on mast cells and basophils leads to cell activation and degranulation upon allergen crosslinking, triggering immediate hypersensitivity (allergic) responses including asthma, rhinitis, and anaphylaxis[5][7][9]. The Fc region's structure allosterically modulates receptor binding and is a primary molecular target for therapies that neutralize IgE or block its effector functions, such as the monoclonal antibody omalizumab[5]. IgE-Fc-mediated mechanisms are also important in defense against parasitic infections[7][9]. High IgE levels or dysregulated IgE-Fc receptor interactions contribute to pathologic inflammation and allergic disease, making the IgE-Fc a validated therapeutic target.

Other names

IgE FcFc region of immunoglobulin EFc epsilon (Fcε)FcεIgE crystallizable fragment

Neutralization of IgE by antibodies (e.g., omalizumab) prevents IgE binding to FcεRI on mast cells and basophils, blocking activation and degranulation[5] - Interference with IgE-Fc binding to its high-affinity (FcεRI) or low-affinity (FcεRII/CD23) receptors, thus inhibiting downstream allergic reactions[1][3][5]