Antibodydependent

Antibody-dependent is an adjective used to describe immune processes that require antibodies to mediate their action, typically through the Fc region of the antibody engaging Fc receptors or activating the complement system. These processes depend on antibodies to recognize a target and to recruit other components of the immune response.

The main antibody-dependent mechanisms include antibody-dependent cellular processes such as ADCP and ADCC. In antibody-dependent cellular phagocytosis (ADCP), phagocytes like macrophages and neutrophils recognize antibody-coated targets via Fc receptors and engulf them. In antibody-dependent cellular cytotoxicity (ADCC), natural killer cells bind to antibody-coated cells through Fc receptors and release cytotoxic molecules to destroy the target. Complement-dependent cytotoxicity (CDC) is another antibody-dependent pathway where antibodies activate the classical complement cascade, leading to target cell lysis. A related, contrasting concept is antibody-dependent enhancement (ADE), in which antibodies can facilitate pathogen entry or replication in certain contexts, potentially worsening disease and influencing vaccine or therapeutic antibody design.

Receptors and cells involved include Fc receptors (such as Fcγ receptors and Fcα receptors) distributed on various immune cells, as well as complement receptors that interact with antibody–complement complexes. The specific antibody isotype, affinity, and epitope targeting can affect the efficiency of these dependent processes.

In clinical and research settings, antibody-dependent mechanisms influence the efficacy of vaccines and therapeutic antibodies, inform the design of antibody-based treatments, and are assessed using assays that measure ADCC, ADCP, and related activities.