Immune tolerance

Definition

Immune tolerance is the state in which the immune system does not attack the body's own cells, tissues, or antigens. This mechanism is crucial for preventing autoimmune disorders, where the immune system mistakenly targets healthy cells, and is fundamental in maintaining homeostasis and ensuring that the immune response is directed appropriately against foreign pathogens while sparing self-components.

5 Must Know Facts For Your Next Test

1. Immune tolerance can be classified into central tolerance, which occurs during lymphocyte development in the thymus and bone marrow, and peripheral tolerance, which takes place after lymphocytes have matured and entered circulation.
2. Mechanisms of immune tolerance include deletion of self-reactive T cells, anergy (functional inactivation), and suppression by regulatory T cells.
3. Failure of immune tolerance can lead to various autoimmune diseases, such as type 1 diabetes, rheumatoid arthritis, and multiple sclerosis.
4. Immune tolerance is not only important for autoimmunity but also plays a significant role in organ transplantation to prevent rejection of transplanted tissues.
5. Research into enhancing immune tolerance is ongoing, with potential implications for treating autoimmune diseases and improving transplant outcomes.

Review Questions

• How does the concept of immune tolerance relate to the development of autoimmune diseases?
  • Immune tolerance is critical in preventing autoimmune diseases because it ensures that the immune system recognizes and spares the body's own cells from attack. When this tolerance breaks down, self-reactive lymphocytes can become activated and target healthy tissues, leading to autoimmune disorders. Therefore, understanding how immune tolerance operates can provide insights into the mechanisms behind conditions such as lupus or multiple sclerosis.
• What roles do regulatory T cells play in maintaining immune tolerance and preventing autoimmune responses?
  • Regulatory T cells (Tregs) are essential for maintaining immune tolerance as they help suppress inappropriate immune responses that could harm the body's own tissues. They exert their effects through various mechanisms, including producing anti-inflammatory cytokines and directly inhibiting other immune cells. By regulating these responses, Tregs are crucial in preventing the development of autoimmune diseases and ensuring that the immune system remains balanced.
• Evaluate the implications of manipulating immune tolerance in clinical settings for patients with autoimmune disorders or those undergoing organ transplants.
  • Manipulating immune tolerance presents significant opportunities in clinical settings. For patients with autoimmune disorders, enhancing immune tolerance could lead to innovative therapies that reset the immune system to stop it from attacking self-tissues. In organ transplantation, inducing tolerance could help prevent rejection without lifelong immunosuppression, reducing complications and improving patient outcomes. However, careful consideration is needed to avoid compromising the ability to fight infections or develop malignancies due to reduced immune responses.

Related terms

Autoimmunity: A condition in which the immune system fails to distinguish between self and non-self, leading to the attack of the body's own tissues.

Tregs (Regulatory T Cells): A subset of T cells that play a key role in maintaining immune tolerance by suppressing excessive immune responses and preventing autoimmunity.

Anaphylaxis: A severe and rapid allergic reaction that occurs when the immune system overreacts to a harmless substance, contrasting with the principle of immune tolerance.