Immune tolerance

Definition

Immune tolerance refers to the state in which the immune system does not mount a response against specific antigens, including self-antigens, thereby preventing autoimmune reactions. This concept is crucial for maintaining homeostasis in the immune system and is particularly important when discussing immunosuppressants and immunomodulators, as these agents can influence the mechanisms of tolerance to protect against unwanted immune responses.

5 Must Know Facts For Your Next Test

1. Immune tolerance can be divided into central tolerance, which occurs during lymphocyte development in the thymus and bone marrow, and peripheral tolerance, which occurs in the peripheral tissues after immune cells have matured.
2. The mechanisms underlying immune tolerance involve both cellular and molecular processes that help to silence autoreactive T and B cells, preventing them from causing harm.
3. Deficiencies in immune tolerance can lead to autoimmune disorders, where the body fails to recognize its own tissues and mounts an attack against them.
4. Immunosuppressants can be used therapeutically to induce immune tolerance in organ transplantation, ensuring that the recipient's immune system does not reject the donor organ.
5. Recent research is exploring how immunomodulators can enhance immune tolerance to treat various conditions, including allergies and autoimmune diseases, by reprogramming the immune response.

Review Questions

• How do T regulatory cells contribute to immune tolerance, and why are they significant in preventing autoimmune diseases?
  • T regulatory cells are essential for maintaining immune tolerance by suppressing the activation and proliferation of autoreactive T cells. They help to regulate immune responses, ensuring that the body does not attack its own tissues. By controlling these potentially harmful immune responses, T regulatory cells play a crucial role in preventing autoimmune diseases and promoting overall immune homeostasis.
• Discuss the different mechanisms through which central and peripheral tolerance are established in the immune system.
  • Central tolerance is established during lymphocyte development in the thymus and bone marrow, where developing T and B cells that recognize self-antigens are eliminated or rendered non-functional. Peripheral tolerance occurs after lymphocytes have matured and involves mechanisms such as anergy, deletion of autoreactive cells in peripheral tissues, and regulation by T regulatory cells. Together, these mechanisms ensure that potentially harmful immune responses against self-antigens are effectively controlled.
• Evaluate the potential benefits and risks of using immunosuppressants to induce immune tolerance in organ transplantation.
  • Using immunosuppressants to induce immune tolerance in organ transplantation can significantly improve graft survival rates by preventing rejection. However, there are risks involved, such as increased susceptibility to infections and malignancies due to a weakened immune response. Evaluating these benefits against potential complications is crucial for optimizing transplant outcomes. The goal is to achieve a balance where grafts are accepted without severely compromising the patient's overall immunity.

Related terms

Autoimmunity: A condition where the immune system mistakenly attacks the body's own tissues, leading to various diseases.

T regulatory cells: A subset of T cells that play a vital role in maintaining immune tolerance by suppressing the activation of the immune response.

Immunosuppression: The reduction of the immune response, often induced by drugs or therapies, to prevent rejection of transplanted organs or to treat autoimmune diseases.