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Table 1 Comparison of central versus peripheral tolerance mechanisms

From: The immunobiology of the mammalian epididymis: the black box is now open!

 

When?

Where?

How?

Central tolerance

Fetal life (setting)

Thymus (T lymphocytes)

Apoptotic death (deletion) of immature self antigen-specific lymphocytes

Throughout life (maintenance)

Bone marrow (B lymphocytes)

Peripheral tolerance

Throughout life

Whole organism (except thymus and bone marrow)

Apoptotic death (deletion) of mature self antigen-sepcific lymphocytes

   

OR

   

Functional inactivation (anergy)

   

OR

   

Suppression of lymphocyte activation and functions by regulatory T cells (Tregs) or by other immunosuppressive effectors such as IDO, kynurenines, cytokines (IL-10), growth factors (TGF-β1)…

  1. Central tolerance is a very early mechanism that is maintained throughout life. It takes place in the primary lymphoid organs (thymus and bone marrow) and consists in the deletion of self antigen-specific B and T cells as soon as they are produced. Peripheral tolerance is set up after central tolerance and is maintained in the whole organism throughout life. Three mechanisms can act: deletion and anergy of mature self antigen-specific lymphocytes, and effector T cell (Th17, Th1, Th2) suppression by regulatory T cells (Tregs) or by immunosuppressive molecules (indoleamine 2,3-dioxygenase = IDO, kynurenines, IL-10, TGF-β1…).
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Basic and Clinical Andrology

ISSN: 2051-4190