Tnf-α

Definition

TNF-α, or tumor necrosis factor-alpha, is a pro-inflammatory cytokine produced mainly by activated macrophages that plays a critical role in cellular and humoral immunity. It is involved in the regulation of immune cells, inflammatory responses, and cell death, making it vital for the body's defense mechanisms against infections and tumors. This cytokine not only enhances the activity of other immune cells but also contributes to systemic inflammation, influencing various physiological processes.

5 Must Know Facts For Your Next Test

1. TNF-α is primarily secreted by activated macrophages and plays a significant role in mediating inflammation.
2. It promotes the activation and proliferation of T-cells and B-cells, enhancing both cellular and humoral immunity.
3. Excessive levels of TNF-α are associated with various inflammatory diseases, such as rheumatoid arthritis and Crohn's disease.
4. This cytokine can induce apoptosis, or programmed cell death, which is important for removing damaged or infected cells from the body.
5. TNF-α interacts with specific receptors on target cells, leading to various signaling pathways that regulate immune responses.

Review Questions

• How does TNF-α influence the activation of immune cells?
  • TNF-α significantly influences the activation of immune cells by promoting the proliferation and differentiation of T-cells and B-cells. This cytokine acts as a signaling molecule that enhances the overall immune response to pathogens. It achieves this by increasing the expression of co-stimulatory molecules on antigen-presenting cells, making them more effective at activating naive T-cells.
• Discuss the role of TNF-α in inflammatory diseases and its potential therapeutic targets.
  • TNF-α plays a pivotal role in the pathogenesis of many inflammatory diseases, including rheumatoid arthritis and inflammatory bowel disease. Elevated levels of this cytokine contribute to chronic inflammation and tissue damage. As a therapeutic target, several anti-TNF-α drugs have been developed to block its action or reduce its production, leading to improved outcomes for patients suffering from these conditions.
• Evaluate the dual role of TNF-α in both promoting immune responses and contributing to tissue damage during chronic inflammation.
  • TNF-α has a dual role in the immune system; it is essential for mounting effective immune responses against infections but can also lead to tissue damage during chronic inflammation. While its pro-inflammatory properties help recruit immune cells to sites of infection, excessive TNF-α production can result in persistent inflammation that damages surrounding tissues. This balance is crucial because dysregulation can lead to autoimmune diseases where the body attacks its own tissues instead of just responding to pathogens.

Related terms

Cytokines: Small proteins released by cells that have a specific effect on the interactions and communications between cells in the immune system.

Macrophages: A type of white blood cell that engulfs and digests cellular debris, foreign substances, and pathogens, acting as key players in the immune response.

Inflammation: The body's protective response to injury or infection, characterized by redness, heat, swelling, and pain, which helps to eliminate the initial cause of cell injury.