Antibody-dependent cell-mediated cytotoxicity

Definition

Antibody-dependent cell-mediated cytotoxicity (ADCC) is an immune response mechanism where antibodies, bound to target cells, facilitate the destruction of those cells by immune effector cells. This process enhances the body's ability to eliminate infected or malignant cells, linking the humoral and cellular immune responses. It plays a crucial role in the recognition and elimination of pathogens, particularly in the context of viral infections and cancer.

5 Must Know Facts For Your Next Test

1. ADCC is primarily mediated by effector cells like Natural Killer (NK) cells, macrophages, and neutrophils that recognize antibody-coated target cells.
2. The binding of antibodies to the Fc receptors on effector cells initiates the ADCC process, leading to the release of cytotoxic substances that kill the target cell.
3. ADCC can effectively target virus-infected cells and tumor cells by marking them for destruction through specific antibodies.
4. This mechanism is utilized in various therapeutic strategies, including monoclonal antibody treatments for cancer, where antibodies target specific tumor antigens to enhance destruction by the immune system.
5. ADCC is different from direct cytotoxic T-cell activity, as it relies on antibodies rather than T-cell receptor recognition of antigens presented on major histocompatibility complex (MHC) molecules.

Review Questions

• How does antibody-dependent cell-mediated cytotoxicity enhance the immune response against infections?
  • Antibody-dependent cell-mediated cytotoxicity enhances the immune response by linking the recognition of pathogen-infected or malignant cells through antibodies with the killing capabilities of immune effector cells. When antibodies bind to specific antigens on these target cells, they act as a bridge for effector cells like Natural Killer (NK) cells. This interaction triggers a response where NK cells release cytotoxic agents that lead to the destruction of the target cell, thus boosting the overall effectiveness of the immune response against infections.
• Discuss the roles of various immune cells involved in antibody-dependent cell-mediated cytotoxicity.
  • Several immune cells play vital roles in antibody-dependent cell-mediated cytotoxicity. Natural Killer (NK) cells are among the primary effectors that recognize antibody-coated target cells via their Fc receptors. Upon recognition, they release perforin and granzymes, leading to target cell lysis. Macrophages and neutrophils also contribute by engulfing antibody-coated targets and releasing inflammatory mediators. The collaboration between these diverse immune cells amplifies the effectiveness of ADCC in combating infections and tumor growth.
• Evaluate how understanding antibody-dependent cell-mediated cytotoxicity could impact therapeutic strategies for cancer treatment.
  • Understanding antibody-dependent cell-mediated cytotoxicity provides critical insights for developing targeted cancer therapies using monoclonal antibodies. By engineering antibodies that bind specifically to tumor antigens, clinicians can leverage ADCC to direct immune effector cells toward cancerous cells. This targeted approach not only enhances tumor elimination but also reduces collateral damage to healthy tissues compared to traditional therapies. Additionally, combining ADCC-based strategies with other immunotherapies may lead to more effective treatments that improve patient outcomes and survival rates.

Related terms

Natural Killer Cells: A type of lymphocyte that plays a critical role in the innate immune response, capable of recognizing and killing infected or transformed cells without prior sensitization.

Monoclonal Antibodies: Laboratory-produced molecules that can mimic the immune system's ability to fight off harmful pathogens such as viruses and bacteria, used in therapies targeting specific antigens.

Complement System: A group of proteins that work with antibodies to destroy pathogens; it can enhance phagocytosis and lead to cell lysis through a series of enzymatic reactions.