title: CCRL1 marks heterogeneity in cortical and medullary thymic epithelial cells.
abstract: Cortical thymic epithelial cells (cTECs) and medullary thymic epithelial cells (mTECs), which play essential roles in the establishment of a functionally competent and self-tolerant repertoire of T cells, are derived from common thymic epithelial progenitor cells (pTECs). Recent findings indicate that mTECs are derived from cells that express molecules that are abundant in cTECs rather than mTECs, and provide fresh insight into the characteristics of pTECs and their diversification pathways into TEC subpopulations. In this issue of the European Journal of Immunology, Ribeiro et al. [Eur. J. Immunol. 2014. 44: 2918-2924] focus on CCRL1, an atypical chemokine receptor that is highly expressed by cTECs rather than mTECs, and show that CCRL1-expressing embryonic TECs can give rise to mTECs. Interestingly, Ribeiro et al. further report that a fraction of postnatal mTECs express CCRL1 at a low level, suggesting novel complexity in mTECs.
authors.affiliation: Division of Experimental Immunology, Institute for Genomic Research, University of Tokushima, Tokushima, Japan.
authors.forename: Izumi
authors.initials: I
authors.lastname: Ohigashi
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Takahama
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000276:immunology*; D004847:Epithelial Cells / Q000166:cytology*; D054388:Receptors, CCR / Q000096:biosynthesis*; D013950:Thymus Gland / Q000166:cytology* / Q000254:growth & development*
chemical_list: D054388:Receptors, CCR
keywords: CCRL1; Cortex; Medulla; Thymic epithelial cell