Related Experiment Videos
Studies on thymic epithelial cells in vitro
K L Anderson1, N C Moore, D E McLoughlin
1Anatomy Department, Medical School, University of Birmingham, UK.
Insights
Thymic epithelial cells (TECs) are crucial for T-cell development. In vitro culture methods significantly impact TEC function, with 3D aggregates preserving their essential capabilities better than 2D cultures.
Area of Science:
- Immunology
- Developmental Biology
- Cell Biology
Background:
- Thymic epithelial cells (TECs) are vital for T-cell development, supporting positive selection and thymocyte maturation.
- Understanding TEC proliferation and function in vitro is crucial for studying thymic development and immunity.
Purpose of the Study:
- To develop a method for measuring TEC proliferation using flow cytometry.
- To investigate the impact of different in vitro culture conditions on TEC function and gene expression.
- To determine the optimal culture strategy for maintaining TEC function in vitro.
Main Methods:
- Developed a flow cytometry technique combining BrdU and pancytokeratin labeling to measure TEC proliferation.
- Assessed TEC proliferation at different gestational days (d15, d16, d18).
- Compared TEC function in organ cultures, 2-deoxyguanosine (2-dGuo)-treated cultures, 3D aggregates, and 2D monolayers.
Main Results:
- TEC proliferation declines significantly from d15 to d18 of gestation.
- TEC proliferation is independent of the lymphoid population, as shown in 2-dGuo-treated cultures.
- Purified TECs in 3D aggregates maintain the ability to support thymocyte maturation and whn gene expression.
- 2D monolayer culture impairs TEC function, reduces whn gene expression, and hinders reaggregate formation.
Conclusions:
- Intact thymic lobes and 3D TEC aggregates are superior for maintaining TEC function and gene expression in vitro.
- Culture method significantly influences TEC behavior, highlighting the importance of 3D structures for preserving function.
- Findings provide a basis for improved in vitro models of thymic epithelial cell biology.
Abstract:
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.