Self-Tolerance

Definition

Self-tolerance is the ability of the immune system to recognize and not mount an immune response against the body's own healthy cells and tissues. It is a crucial mechanism that prevents autoimmune diseases by ensuring the immune system does not attack the host's own cells.

5 Must Know Facts For Your Next Test

1. Self-tolerance is essential for preventing autoimmune diseases, where the immune system attacks the body's own healthy cells and tissues.
2. Central tolerance mechanisms in the thymus and bone marrow eliminate or inactivate self-reactive T cells and B cells during their development.
3. Peripheral tolerance mechanisms, such as anergy, deletion, and suppression by regulatory T cells, maintain self-tolerance in mature lymphocytes that have escaped central tolerance.
4. Breakdown in self-tolerance can lead to the development of various autoimmune disorders, including type 1 diabetes, rheumatoid arthritis, and systemic lupus erythematosus.
5. Understanding the mechanisms of self-tolerance is crucial for developing therapies to treat autoimmune diseases and for designing effective vaccines that do not induce autoimmunity.

Review Questions

• Explain the role of self-tolerance in the context of specific adaptive immunity (18.1 Overview of Specific Adaptive Immunity)
  • Self-tolerance is a critical component of the specific adaptive immune response, as it ensures that the immune system does not mount an attack against the body's own healthy cells and tissues. By eliminating or inactivating self-reactive T cells and B cells during their development in the thymus and bone marrow (central tolerance), and maintaining tolerance in mature lymphocytes through peripheral tolerance mechanisms, the immune system is able to recognize and respond to foreign pathogens while avoiding autoimmunity. This delicate balance between self-tolerance and the ability to mount an effective adaptive immune response is essential for maintaining homeostasis and protecting the host from both infectious agents and autoimmune diseases.
• Describe how a breakdown in self-tolerance can lead to the development of autoimmune disorders (19.2 Autoimmune Disorders)
  • A breakdown in self-tolerance can result in the development of autoimmune disorders, where the immune system mistakenly attacks the body's own healthy cells and tissues. This can occur due to failures in central tolerance mechanisms that allow self-reactive lymphocytes to escape elimination or inactivation during their development, or due to breakdowns in peripheral tolerance that allow these self-reactive cells to become activated and mount an autoimmune response. The specific autoimmune disorder that develops depends on the target of the autoimmune attack, which can range from the pancreatic beta cells in type 1 diabetes to the joint tissues in rheumatoid arthritis. Understanding the mechanisms underlying the loss of self-tolerance is crucial for developing effective therapies to treat autoimmune diseases and prevent their onset.
• Evaluate the importance of self-tolerance in the context of both specific adaptive immunity and autoimmune disorders, and discuss the potential implications for the development of immunotherapies
  • Self-tolerance is a fundamental concept that underpins the delicate balance between the immune system's ability to mount a protective response against pathogens and the need to avoid attacking the body's own healthy cells and tissues. In the context of specific adaptive immunity, self-tolerance mechanisms ensure that self-reactive lymphocytes are eliminated or inactivated, allowing the immune system to effectively recognize and respond to foreign antigens without triggering autoimmunity. Conversely, a breakdown in self-tolerance can lead to the development of autoimmune disorders, where the immune system mistakenly attacks the host's own cells and tissues. Understanding the complex mechanisms that regulate self-tolerance, including central tolerance in the thymus and bone marrow, as well as peripheral tolerance in mature lymphocytes, is crucial for the development of effective immunotherapies. By leveraging this knowledge, researchers can design targeted therapies that either restore self-tolerance to treat autoimmune diseases or overcome self-tolerance to enhance the immune system's ability to recognize and eliminate cancer cells. The careful balance and interplay between self-tolerance and immune responsiveness is a key area of ongoing research, with significant implications for the future of personalized medicine and immunotherapy.

Related terms

Autoimmunity: A condition where the immune system mistakenly attacks the body's own healthy cells and tissues, leading to autoimmune disorders.

Central Tolerance:

The process by which self-reactive T cells and B cells are eliminated or inactivated during their development in the thymus and bone marrow, respectively.

Peripheral Tolerance:

The mechanisms that maintain self-tolerance in mature T cells and B cells that have escaped central tolerance, including anergy, deletion, and suppression by regulatory T cells.