title: Heterogeneity of epithelial cells in the rat thymus.
abstract: The morphological heterogeneity of the thymic epithelium has been well documented both at the light and electron microscopic level. Immunohistochemistry has revealed four broad classes of epithelial cells (EC): subcapsule/perivascular, cortical, medullary EC, and medullary Hassall's corpuscles. Ultrastructural analysis has revealed further heterogeneity. In the cortex, four EC subtypes have been described ultrastructurally: subcapsular/perivascular, "pale," "intermediate," and "dark" EC. These subtypes are also present in the medulla. Two additional EC subtypes are restricted to the medulla: an undifferentiated subtype, and a subtype displaying signs of high metabolic activity. Based on the morphological features of the epithelium, it has been hypothetized that the thymic EC subtypes represent a process of differentiation.
authors.affiliation: National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands.
authors.forename: E J
authors.initials: EJ
authors.lastname: De Waal
authors.forename: L H
authors.initials: LH
authors.lastname: Rademakers
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D004847:Epithelial Cells; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D051381:Rats; D013950:Thymus Gland / Q000166:cytology* / Q000648:ultrastructure