Intrathymic Selection and Defects in the Thymic Epithelial Cell Development

• Published in: Cells (Basel, Switzerland) Switzerland), 2020-10, Vol.9 (10), p.2226
• Main Authors: García-Ceca, Javier, Montero-Herradón, Sara, Zapata, Agustín G.
• Format: Article
• Language: English
• Subjects: Antigens; Cell adhesion; Cell development (Biology); Cell differentiation; Eph/ephrins; Ephrins; Epithelial cells; Immunosurveillance; Ligands; Lymphocytes T; Peptides; Physiological aspects; Physiological research; Population; regulatory T-cells; Review; thymic epithelial cells; thymocyte education; Thymocytes; Thymus; Thymus gland
• ISSN: 2073-4409; 2073-4409
• DOI: 10.3390/cells9102226

Intimate interactions between thymic epithelial cells (TECs) and thymocytes (T) have been repeatedly reported as essential for performing intrathymic T-cell education. Nevertheless, it has been described that animals exhibiting defects in these interactions were capable of a proper positive and negative T-cell selection. In the current review, we first examined distinct types of TECs and their possible role in the immune surveillance. However, EphB-deficient thymi that exhibit profound thymic epithelial (TE) alterations do not exhibit important immunological defects. Eph and their ligands, the ephrins, are implicated in cell attachment/detachment and govern, therefore, TEC–T interactions. On this basis, we hypothesized that a few normal TE areas could be enough for a proper phenotypical and functional maturation of T lymphocytes. Then, we evaluated in vivo how many TECs would be necessary for supporting a normal T-cell differentiation, concluding that a significantly low number of TEC are still capable of supporting normal T lymphocyte maturation, whereas with fewer numbers, T-cell maturation is not possible.