Thymic cysts originate from Foxn1 positive thymic medullary epithelium

Eric Vroegindeweij, Stijn Crobach, M Itoi, R Satoh, S Zuklys, C Happe, WTV Germeraad, Jan Cornelissen, Tom Cupedo, GA Hollander, H Kawamoto, W van Ewijk

Research output: Contribution to journalArticleAcademicpeer-review

15 Citations (Scopus)


Thymic epithelial cells (TECs), derived from polarized two-dimensional (2D) oriented endodermal cells, are distinguished from other epithelial cells by their unique three-dimensional (3D) phenotype However, sonic polarized epithelial cells remain present in the normal thymus, forming thymic cysts at the cortico-medullary junction Here, we analyse the dynamics, origin and phenotype of such thymic cysts. In time-course experiments, we show a reverse correlation between thymic cyst expansion and the presence of thymocytes, suggesting a default pathway for the development of TECs in the absence of thymocytes By transplanting isolated TEC Populations into El 5 fetal thymic lobes, we provide evidence that medullary thymic epithelial cells (mTECs), rather than cortical thymic epithelial cells (cTECs) contribute to the formation of thymic cysts Finally, thymi of reporter mice reveal that the cysts originate from epithelia committed to a thymic fate, as indicated by the expression of Foxn1. The 2D-phenotype of cyst-lining TECs is not caused by a downregulation of Foxn1 expression. since a significant proportion of these cells in the embryonic and adult thymus continues to express Foxn1 at the protein level. (C) 2009 Elsevier Ltd All rights reserved
Original languageUndefined/Unknown
Pages (from-to)1106-1113
Number of pages8
JournalMolecular Immunology
Issue number5
Publication statusPublished - 2010

Cite this