Regulatory T Cells

Definition

Regulatory T cells, or Tregs, are a specialized subset of T cells that play a crucial role in maintaining immune tolerance and preventing autoimmunity by suppressing immune responses. They help to regulate the immune system's activity, ensuring it does not overreact to harmless substances or the body’s own tissues, which is essential for a balanced immune response.

5 Must Know Facts For Your Next Test

1. Regulatory T cells express the transcription factor FoxP3, which is critical for their development and function.
2. Tregs can be divided into natural and induced types; natural Tregs develop in the thymus while induced Tregs are generated in peripheral tissues in response to specific signals.
3. One of the main mechanisms through which Tregs exert their function is by secreting inhibitory cytokines such as IL-10 and TGF-β.
4. Dysfunction or deficiency of regulatory T cells is linked to various autoimmune diseases and inflammatory conditions, where the immune system fails to regulate itself properly.
5. In cancer therapy, regulatory T cells can sometimes hinder effective anti-tumor responses, leading to ongoing research into strategies that target Tregs to enhance immunotherapy.

Review Questions

• How do regulatory T cells contribute to immune tolerance within the immune system?
  • Regulatory T cells play a vital role in promoting immune tolerance by suppressing excessive immune responses against self-antigens and foreign substances. They achieve this through various mechanisms such as the secretion of inhibitory cytokines like IL-10 and TGF-β, which dampen the activity of other immune cells. By maintaining this balance, Tregs prevent autoimmune reactions and ensure that the immune system can distinguish between harmful pathogens and harmless entities.
• Discuss the differences between natural regulatory T cells and induced regulatory T cells in terms of their development and function.
  • Natural regulatory T cells develop in the thymus during the maturation of T cells and are essential for maintaining self-tolerance from an early age. In contrast, induced regulatory T cells are generated in peripheral tissues when conventional T cells encounter specific antigens under particular conditions, often involving cytokine signals. Both types share similar functions in suppressing immune responses, but their developmental origins highlight different pathways through which immune regulation is achieved.
• Evaluate the implications of regulatory T cell dysfunction in autoimmune diseases and cancer therapies.
  • Dysfunction or inadequate numbers of regulatory T cells can lead to autoimmune diseases because without proper suppression, the immune system may attack its own tissues. This highlights their importance in maintaining self-tolerance. Conversely, in cancer therapies, regulatory T cells may inhibit effective anti-tumor responses by suppressing effector T cell activity. Understanding these dynamics has prompted research into manipulating Treg functions to improve therapeutic outcomes, illustrating their dual roles in health and disease.

Related terms

Cytokines: Small signaling molecules released by cells that influence the behavior of other cells, playing a key role in cell communication and the immune response.

Autoimmunity: A condition arising from an inappropriate immune response against the body’s own tissues, which can be modulated by the actions of regulatory T cells.

Immune Tolerance: The process by which the immune system learns to recognize and not respond to self-antigens, significantly influenced by regulatory T cells.