Peripheral tolerance
Peripheral Tolerance
Peripheral tolerance (pronunciation: puh-rif-er-uhl tol-er-uhns) is a mechanism by which the immune system avoids attacking the body's own cells and tissues, thus preventing autoimmunity. This process occurs in the peripheral lymphoid organs, where mature lymphocytes are exposed to self-antigens.
Etymology
The term "peripheral tolerance" is derived from the words "peripheral," which refers to the outer areas of the body, and "tolerance," which in this context refers to the immune system's ability to tolerate the presence of self-antigens without initiating an immune response.
Mechanisms of Peripheral Tolerance
Peripheral tolerance is achieved through several mechanisms, including anergy, immunological ignorance, regulatory T cells, and clonal deletion.
- Anergy is a state of unresponsiveness by T cells or B cells to antigen stimulation. This can occur when the cell receives a signal from the antigen but not from co-stimulatory molecules.
- Immunological ignorance refers to the immune system's lack of response to self-antigens due to their low concentration or sequestration in certain areas of the body.
- Regulatory T cells (Tregs) play a crucial role in maintaining peripheral tolerance by suppressing the activation and proliferation of self-reactive lymphocytes.
- Clonal deletion involves the removal of self-reactive lymphocytes through apoptosis, or programmed cell death.
Related Terms
- Central tolerance: This is the process by which self-reactive T cells and B cells are eliminated or altered in the thymus or bone marrow, respectively, during their development.
- Autoimmunity: This is a condition in which the immune system mistakenly attacks the body's own cells and tissues.
- Immunological tolerance: This is the immune system's ability to distinguish between self and non-self antigens and to respond appropriately.
See Also
External links
- Medical encyclopedia article on Peripheral tolerance
- Wikipedia's article - Peripheral tolerance
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