Differential processing of self-antigens by subsets of thymic stromal cells

Curr Opin Immunol. 2012 Feb;24(1):99-104. doi: 10.1016/j.coi.2012.01.008. Epub 2012 Jan 30.


The stromal network of the thymus provides a unique environment that supports the development of mature CD4(+) and CD8(+) T cells expressing a very diverse repertoire of T cell receptors (TCR) with limited reactivity to self-antigens. Thymic cortical epithelial cells (cTECs) are specialized antigen-presenting cells (APCs) that promote the positive selection of developing thymocytes while medullary thymic epithelial cells (mTECs) and thymic dendritic cells (tDCs) induce central tolerance to self-antigens. Recent studies showed that cTECs express a unique set of proteases involved in the generation of self-peptides presented by major-histocompatibility encoded molecules (pMHC) and consequently may express a unique set of pMHC complexes. Conversely, the stromal cells of the medulla developed several mechanisms to mirror as closely as possible the constellation of self-peptides derived from peripheral tissues. Here, we discuss how these different features allow for the development of a highly diverse but poorly self-reactive repertoire of functional T cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Antigen Presentation / immunology*
  • Antigen-Presenting Cells / immunology*
  • Autoantigens / immunology*
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Epithelial Cells / immunology
  • Humans
  • Receptors, Antigen, T-Cell / immunology
  • Thymus Gland / immunology*


  • Autoantigens
  • Receptors, Antigen, T-Cell