Intrathymic Selection and Defects in the Thymic Epithelial Cell Development

• Main Authors: Javier García-Ceca, Sara Montero-Herradón, Agustín G. Zapata
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Cells
• Subjects: thymic epithelial cells; thymocyte education; regulatory T-cells; Eph/ephrins
• Online Access: https://www.mdpi.com/2073-4409/9/10/2226

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.