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CD5- dendritic epidermal T cells are derived from CD5+ precursor cells
1Department of Dermatology, University of Vienna Medical School, Vienna International Research Cooperation Center, Vienna, Austria.
European Journal of Immunology
|June 1, 1994
Summary
Murine dendritic epidermal T cells (DETC) are CD5-negative, but their precursors express CD5. This study shows CD5 expression is downregulated during DETC maturation and migration to the epidermis.
Area of Science:
- Immunology
- T cell development
- Cell surface markers
Background:
- Murine Thy-1+, TcR V gamma 3/V delta 1+ dendritic epidermal T cells (DETC) are unique among T cell subsets due to their lack of CD4, CD8, and CD5 expression.
- The developmental stage at which these antigens are downregulated is unclear, leaving open whether their absence is an intrinsic feature or a maturational characteristic.
Purpose of the Study:
- To investigate the phenotype of TcR V gamma 3+ fetal thymocytes, the precursor cells of DETC, to determine if they express CD4, CD8, and CD5.
- To trace the expression of CD5 on DETC precursors during intrathymic maturation and migration to the fetal skin.
- To understand the regulation of CD5 expression during T cell development.
Main Methods:
- Phenotypic analysis of TcR V gamma 3+ fetal thymocytes using flow cytometry.
- In vivo studies involving the injection of fetal thymic suspensions into athymic nude mice.
- In vitro culture of TcR V gamma 3+ cells with and without PMA and ionomycin.
Main Results:
- TcR V gamma 3+ fetal thymocytes, precursors of DETC, express CD5, CD8, and some express CD4, differing from mature CD5-negative DETC.
- Injection of CD5+ TcR V gamma 3+ thymocytes into nude mice led to the appearance of CD5-negative donor-type DETC in the epidermis.
- CD5 expression is progressively downregulated on TcR V gamma 3+ cells during intrathymic maturation, fetal blood circulation, and epidermal migration, a process not prevented by PMA/ionomycin.
Conclusions:
- TcR V gamma 3+ thymocytes are indeed precursors of CD5-negative DETC, with CD5 downregulation being a critical step in their maturation.
- The study establishes a model system to investigate the function of CD5 and the mechanisms regulating its expression during T cell development.
- This research provides insights into the developmental trajectory of a unique T cell subset and the regulation of cell surface marker expression.