Studies on thymic epithelial cells in vitro.
Thymic epithelial cells are unique in their ability to support positive selection and are essential throughout thymocyte development. Here, we describe a technique for measuring the proliferation of thymic epithelial cells by flow cytometry using a combination of BrdU and pancytokeratin labelling, and we examine the effects of different in vitro culture strategies on thymic epithelial cell function. We find that at d15 gestation, 74% (+/- 0.4%) of thymic epithelial cells are in cycle, which declines to 63% (+/- 1.3%) by d16, and to 34% (+/- 1.9%) by d18. This decline in proliferation is also found in organ cultures and in cultures depleted of lymphoid cells by 2-dGuo, suggesting that the cell cycle status of thymic epithelial cells is independent of the lymphoid population. When cultured in vitro as 3-dimensional aggregates, purified MHC class II+ thymic epithelial cells retain the ability to support thymocyte maturation. In contrast, 2-dimensional monolayer culture abrogates the ability of these cells to support positive selection, causes a reduction in whn gene expression and reduces their ability to re-form coherent reaggregate structures. Intact lobes and 3-dimensional aggregates are therefore the best way of maintaining thymic epithelial cell function and gene expression in vitro.
Anatomy Department, Medical School, University of Birmingham, UK.
K L
KL
Anderson
N C
NC
Moore
D E
DE
McLoughlin
E J
EJ
Jenkinson
J J
JJ
Owen
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism; D015870:Gene Expression; D000949:Histocompatibility Antigens Class II; D051379:Mice; D008807:Mice, Inbred BALB C; D013950:Thymus Gland / Q000166:cytology* / Q000196:embryology
D000949:Histocompatibility Antigens Class II