Sphingosine-1-phosphate receptor 2 restrains egress of {gamma}{delta} T cells from the skin

Maintenance of a population of IL-17–committed T cells in the dermis is important in promoting tissue immunity. However, the signals facilitating T cell retention within the dermis remain poorly understood. Here, we find that sphingosine-1-phosphate receptor 2 (S1PR2) acts in a cell-intrinsic manner to oppose T cell migration from the dermis to the skin draining lymph node (dLN). Migration of dermal T cells to the dLN under steady-state conditions occurs in an S1PR1-dependent manner. S1PR1 and CD69 are reciprocally expressed on dermal T cells, with loss of CD69 associated with increased S1PR1 expression and enhanced migration to the dLN. T cells lacking both S1PR2 and CD69 are impaired in their maintenance within the dermis. These findings provide a mechanism for how IL-17+ T cells establish residence within the dermis and identify a role for S1PR2 in restraining the egress of tissue-resident lymphocytes.

Source: The Journal of Experimental Medicine - June 30, 2019 Category: Internal Medicine Authors: Laidlaw, B. J., Gray, E. E., Zhang, Y., Ramirez-Valle, F., Cyster, J. G. Tags: Mucosal Immunology Brief Definitive Reports Source Type: research