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Examination of Thymic Positive and Negative Selection by Flow Cytometry
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Examination of Thymic Positive and Negative Selection by Flow Cytometry

Published on: October 8, 2012

Presentation of neuroendocrine self in the thymus: a necessity for integrated evolution of the immune and

Vincent Geenen1

  • 1University of Liege, GIGA-Research Center of Immunoendocrinology, Sart Tilman, Belgium. vgeenen@ulg.ac.be

Annals of the New York Academy of Sciences
|July 25, 2012
PubMed

During evolution, from ancestor thymoids scattered in gill baskets of the lamprey, the first unique thymus appeared in jawed cartilaginous fishes around 450-500 millions years ago, concomitantly or shortly after the emergence of recombinase-dependent adaptive immunity. The major biological function of the thymus is to generate a diverse repertoire of T cell receptors that are self tolerant. The thymus achieves this role by using two complementary and intimately associated mechanisms: apoptotic deletion of T cell clones bearing a TCR with high affinity for self-antigens presented by MHC proteins on thymic epithelial cells (TECs) and dendritic cells (DCs); and generation of self-antigen-specific natural regulatory T (nT(reg)) cells. Moreover, the escape from thymic central self-tolerance plays a primary role in the development of autoimmune diseases that are a significant burden for the quality of life and health-care cost. Our new knowledge in thymus physiology and physiopathology is currently translated into innovative therapeutic strategies against these devastating chronic diseases.

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