Natural Killer Cells

Definition

Natural killer (NK) cells are a type of cytotoxic lymphocyte that play a crucial role in the body's innate immune response. They are able to recognize and destroy infected, stressed, or cancerous cells without prior sensitization, making them an important component of the Biologic Response Modifiers.

5 Must Know Facts For Your Next Test

1. Natural killer cells are able to recognize and kill cells that are missing or have reduced expression of self-MHC class I molecules, a common feature of virus-infected and tumor cells.
2. NK cells release cytotoxic granules containing perforin and granzymes, which can induce apoptosis in target cells.
3. The activation of NK cells is regulated by a balance of activating and inhibitory signals, including the interaction of NK cell receptors with MHC class I molecules on target cells.
4. NK cells play a crucial role in the body's defense against viral infections and in the surveillance and elimination of tumors.
5. Certain cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-γ), can enhance the cytotoxic activity of NK cells.

Review Questions

• Describe the role of natural killer cells in the innate immune response.
  • Natural killer cells are a key component of the innate immune system, as they are able to recognize and destroy infected, stressed, or cancerous cells without prior sensitization. They accomplish this through the release of cytotoxic granules containing perforin and granzymes, which can induce apoptosis in target cells. The activation of NK cells is regulated by a balance of activating and inhibitory signals, including the interaction of NK cell receptors with MHC class I molecules on target cells.
• Explain how natural killer cells contribute to the body's defense against viral infections and tumor surveillance.
  • Natural killer cells play a crucial role in the body's defense against viral infections and in the surveillance and elimination of tumors. They are able to recognize and kill cells that are missing or have reduced expression of self-MHC class I molecules, a common feature of virus-infected and tumor cells. Certain cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-γ), can enhance the cytotoxic activity of NK cells, further strengthening their ability to target and destroy these abnormal cells.
• Discuss the significance of natural killer cells in the context of Biologic Response Modifiers and their potential therapeutic applications.
  • Natural killer cells are an important component of the Biologic Response Modifiers, as they play a crucial role in the body's innate immune response. Their ability to recognize and destroy infected, stressed, or cancerous cells without prior sensitization makes them a valuable target for potential therapeutic interventions. Researchers are exploring ways to harness the cytotoxic capabilities of NK cells, such as through the use of cytokines like IL-2 and IFN-γ, to enhance their anti-tumor and anti-viral activities. Understanding the regulation and function of natural killer cells is crucial for the development of novel immunotherapies and Biologic Response Modifiers that can effectively combat a range of diseases.

Related terms

Cytotoxic Lymphocytes: A type of lymphocyte that can directly kill target cells, including virus-infected cells and tumor cells.

Innate Immune Response: The body's first line of defense against pathogens, which does not require prior exposure or sensitization.

Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC): A mechanism by which NK cells can recognize and destroy target cells that are coated with antibodies.