Fc region of antibody (Fc region)

The **Fc region of antibody** (Fragment crystallizable region) is the constant tail portion of an antibody molecule that interacts with cell surface Fc receptors on immune cells (such as macrophages, NK cells, and neutrophils) and with components of the complement system[1][2][7]. This region mediates effector functions such as antibody-dependent cellular cytotoxicity, phagocytosis, and complement activation[1][7]. The Fc region determines the isotype of the antibody (e.g., IgG, IgA, IgE) and is structurally composed of the constant domains of the heavy chains, with distinct features depending on antibody class (e.g., presence or absence of glycosylation, domain architecture)[1][2][5]. Therapeutically, many monoclonal antibodies leverage the Fc region to recruit immune effector mechanisms for disease treatment, especially in cancer, autoimmune disorders, and infections[1][7]. **Note:** - The submitted target "Fc region of target-bound antibodies" is not a conventional therapeutic target by itself. Instead, it is a structural component of an antibody that becomes functionally relevant after the antibody binds its target, enabling recruitment of the immune system via interaction with Fc receptors and complement proteins[1][2][7]. - While many therapeutic agents are designed to exploit Fc-dependent mechanisms (e.g., engineered antibodies with optimized Fc regions), the Fc region itself is not typically targeted by drugs but rather is a mediator of immune activity. - Some experimental therapeutics (such as Fc receptor blockers or engineered bispecifics) target Fc-Fc receptor interactions, but "Fc region of target-bound antibodies" is not a single defined molecule or conventional receptor, enzyme, etc. - This entry is therefore likely to be flagged as "is_incorrect: true" due to its ambiguous and structural, not molecular, target nature.

Other names

Fragment crystallizable regionFc fragmentFc domainFc portion

Antibody-dependent cellular cytotoxicity (ADCC), Antibody-dependent cellular phagocytosis (ADCP), Complement-dependent cytotoxicity (CDC), Inhibition or stimulation of immune cell signaling via Fc receptors