Aryl hydrocarbon receptor is critical for homeostasis of invariant γδ T cells in the murine epidermis

S Kadow, B Jux, SP Zahner, B Wingerath… - The Journal of …, 2011 - journals.aai.org
S Kadow, B Jux, SP Zahner, B Wingerath, S Chmill, BE Clausen, J Hengstler, C Esser
The Journal of Immunology, 2011journals.aai.org
An immunoregulatory role of aryl hydrocarbon receptor (AhR) has been shown in
conventional αβ and γδ T cells, but its function in skin γδ T cells (dendritic epidermal T cells
[DETC]) is unknown. In this study, we demonstrate that DETC express AhR in wild-type mice,
and are specifically absent in the epidermis of AhR-deficient mice (AhR-KO). We show that
DETC precursors are generated in the thymus and home to the skin. Proliferation of DETC in
the skin was impaired in AhR-KO mice, resulting in a> 90% loss compared with wild type …
Abstract
An immunoregulatory role of aryl hydrocarbon receptor (AhR) has been shown in conventional αβ and γδ T cells, but its function in skin γδ T cells (dendritic epidermal T cells [DETC]) is unknown. In this study, we demonstrate that DETC express AhR in wild-type mice, and are specifically absent in the epidermis of AhR-deficient mice (AhR-KO). We show that DETC precursors are generated in the thymus and home to the skin. Proliferation of DETC in the skin was impaired in AhR-KO mice, resulting in a> 90% loss compared with wild type. Surprisingly, DETC were not replaced by αβ T cells or conventional γδ T cells, suggesting a limited time frame for seeding this niche. We found that DETC from AhR-KO mice failed to express the receptor tyrosine kinase c-Kit, a known growth factor for γδ T cells in the gut. Moreover, we found that c-kit is a direct target of AhR, and propose that AhR-dependent c-Kit expression is potentially involved in DETC homeostasis. DETC are a major source of GM-CSF in the skin. Recently, we had shown that impaired Langerhans cell maturation in AhR-KO is related to low GM-CSF levels. Our findings suggest that the DETCs are necessary for LC maturation, and provide insights into a novel role for AhR in the maintenance of skin-specific γδ T cells, and its consequences for the skin immune network.
journals.aai.org