Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)

Definition

Antibody-dependent cell-mediated cytotoxicity (ADCC) is an immune response mechanism in which antibodies bound to target cells, such as cancer cells or virus-infected cells, trigger the destruction of those cells by effector cells, such as natural killer (NK) cells or macrophages. This process is a crucial component of the immune system's defense against certain diseases.

5 Must Know Facts For Your Next Test

1. ADCC is an important mechanism in the immune system's response to cancer and viral infections, as it can help eliminate transformed or infected cells.
2. The process of ADCC involves the binding of antibodies to specific antigens on the surface of target cells, which then recruit and activate effector cells, such as NK cells and macrophages, to destroy the marked cells.
3. ADCC is mediated by the Fc region of the antibody, which interacts with Fc receptors on the surface of effector cells, triggering their cytotoxic response.
4. The effectiveness of ADCC can be influenced by the type of antibody, the density of target antigens, and the activation state of the effector cells involved.
5. ADCC is a key mechanism in the action of some monoclonal antibody-based cancer therapies, where the antibodies bind to tumor cells and recruit immune effector cells to destroy them.

Review Questions

• Explain the role of ADCC in the immune system's response to cancer and viral infections.
  • ADCC is an important mechanism in the immune system's defense against cancer and viral infections. In this process, antibodies bind to specific antigens on the surface of transformed or infected cells, marking them for destruction by effector cells such as natural killer (NK) cells and macrophages. The binding of the antibody's Fc region to Fc receptors on the effector cells triggers their cytotoxic response, leading to the lysis and elimination of the target cells. This ADCC-mediated killing of cancer cells and virus-infected cells is a crucial component of the immune system's efforts to control the spread of these diseases.
• Describe how the effectiveness of ADCC can be influenced by different factors.
  • The effectiveness of ADCC can be influenced by several factors, including the type of antibody involved, the density of target antigens on the surface of the target cells, and the activation state of the effector cells. The specific antibody isotype and its ability to bind to Fc receptors on effector cells can impact the strength of the ADCC response. The number and distribution of target antigens on the cell surface can also affect the efficiency of antibody binding and the subsequent recruitment of effector cells. Additionally, the activation state of the effector cells, such as natural killer (NK) cells and macrophages, can influence their cytotoxic capabilities and the overall potency of the ADCC-mediated immune response.
• Explain how ADCC is utilized in the development of monoclonal antibody-based cancer therapies.
  • ADCC is a key mechanism in the action of some monoclonal antibody-based cancer therapies. In these treatments, the administered monoclonal antibodies bind to specific antigens expressed on the surface of tumor cells. This antibody binding then recruits and activates immune effector cells, such as natural killer (NK) cells and macrophages, to destroy the marked cancer cells through the ADCC process. The effectiveness of these therapies can be influenced by factors like the antibody's ability to bind to Fc receptors on effector cells, the density of target antigens on the tumor cells, and the activation state of the recruited immune cells. By harnessing the ADCC-mediated killing of cancer cells, monoclonal antibody-based therapies can enhance the immune system's ability to fight and eliminate certain types of malignancies.

Related terms

Antibody: A protein produced by B cells that recognizes and binds to specific foreign substances, such as pathogens or cancer cells, to neutralize or mark them for destruction by other immune cells.

Natural Killer (NK) Cells:

A type of lymphocyte that can directly kill infected or transformed cells without prior sensitization, and also play a role in ADCC by binding to antibody-coated target cells and triggering their lysis.

Effector Cells: Immune cells that carry out the direct killing or removal of target cells, such as NK cells, macrophages, and cytotoxic T cells, which can be activated by the binding of antibodies to target cells in the ADCC process.