Histogenesis of the epithelial component of rat thymus: An ultrastructural and immunohistological analysis

Appearance and Maturation of T‐Cell Subsets During Rat Thymus Ontogeny

“…As previously reported (Vicente et al, 1996), the first T-cell precursors reached the rat thymus anlage at days 13-14 of gestation. These progenitor cells expressed CD45, CD53, and CD43 antigens ( Figure a).…”

“…Rat thymus anlage is colonized by cell precursors around days 13-14 of gestation (Vicente et al, 1996). These cells largely expressed CD45, CD43, and CD53 antigens.…”

“…Their appearance involves the fully maturation of thymic epithelial cells, the histological differentiation of a thymic cortex and the increase of both expression and number of MHC class I and class II positive cells (days 18-19) (Vicente et al, 1996).…”

“…The upregulation of TcRce/3/CD3 complex in the DP cells and the strong expression of MHC molecules on both epithelial cells and dendritic cells (Vicente et al, 1994(Vicente et al, , 1996 allow the intrathymic thymocyte selection. Nonselected apoptotic cells are eliminated by thymic macrophages, which mature in the last days of fetal life (Vicente et al, 1995).…”

“…Previously, we studied the ontogeny of rat thymic stromal-cell components, including epithelial cells, dendritic cells, and macrophages (Vicente et al, 1994(Vicente et al, , 1995(Vicente et al, , 1996. In the present study, we combine both immunohistochemistry and flow cytometry to analyze the appearance and differentiation of distinct rat T-cell subsets and /he influence of the thymic nonlymphoid cell microenvironments on these processes.…”