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UVB-irradiated dendritic cells induce nonproliferating, regulatory type T cells
J C Simon1, H Hara, R W Denfeld
1Department of Dermatology, University of Freiburg, Freiburg, Germany. jancsimon@haut.ukl.uni-freiburg.de
Skin Pharmacology and Applied Skin Physiology
|September 20, 2002
Summary
Low-dose UVB radiation generates regulatory T cells from dendritic cells. These UVB-induced T cells suppress naive T cell proliferation and increase TGF-beta, suggesting a tolerogenic immune response.
Area of Science:
- Immunology
- Dermatology
- Cell Biology
Background:
- Low-dose ultraviolet B (UVB) radiation is known to inhibit antigen-presenting cell (APC) function in Langerhans cells.
- UVB-irradiated dendritic cells (UVB-DC) suppress T cell proliferation and tolerize primed T cells.
Purpose of the Study:
- To investigate the mechanism by which UVB-irradiated dendritic cells (UVB-DC) affect T cell responses.
- To determine if UVB-DC induce regulatory T cells.
Main Methods:
- Coculture of naive OVA-specific T cells with unirradiated dendritic cells (DC) or UVB-DC.
- Flow cytometry (FACS) analysis of T cell activation markers (CD25, CD69).
- Enzyme-linked immunosorbent assay (ELISA) to measure cytokine levels (IFN-gamma, IL-2, IL-4, TGF-beta).
Main Results:
- UVB-DC dose-dependently inhibited OVA-specific T cell proliferation.
- T cells cocultured with UVB-DC showed an activated phenotype but reduced proliferation upon restimulation.
- Supernatants from UVB-DC cocultures had decreased pro-inflammatory cytokines but increased TGF-beta.
- Nonproliferating T cells from UVB-DC cocultures suppressed naive T cell proliferation.
Conclusions:
- UVB-irradiated dendritic cells (UVB-DC) induce nonproliferating T cells with regulatory functions.
- These regulatory T cells exhibit increased TGF-beta production and suppress naive T cell proliferation.
- UVB-DC promote a tolerogenic immune response by generating regulatory T cells.