Programmed cell death 1 (PD-1) regulates the effector function of CD8 T cells via PD-L1 expressed on target keratinocytes.

Programmed cell death 1 (PD-1) regulates the effector function of CD8 T cells via PD-L1 expressed on target keratinocytes. J Autoimmun. 2014 Jul 18; Authors: Okiyama N, Katz SI Abstract Programmed cell death 1 (PD-1) is an inhibitory molecule expressed by activated T cells. Its ligands (PD-L1 and -L2; PD-Ls) are expressed not only by a variety of leukocytes but also by stromal cells. To assess the role of PD-1 in CD8 T cell-mediated diseases, we used PD-1-knockout (KO) OVA-specific T cell-receptor transgenic (Tg) CD8 T cells (OT-I cells) in a murine model of mucocutaneous graft-versus-host disease (GVHD). We found that mice expressing OVA on epidermal keratinocytes (K14-mOVA mice) developed markedly enhanced GVHD-like disease after transfer of PD-1-KO OT-I cells as compared to those mice transferred with wild-type OT-I cells. In addition, K14-mOVA × OT-I double Tg (DTg) mice do not develop GVHD-like disease after adoptive transfer of OT-I cells, while transfer of PD-1-KO OT-I cells caused GVHD-like disease in a Fas/Fas-L independent manner. These results suggest that PD-1/PD-Ls-interactions have stronger inhibitory effects on pathogenic CD8 T cells than does Fas/Fas-L-interactions. Keratinocytes from K14-mOVA mice with GVHD-like skin lesions express PD-L1, while those from mice without the disease do not. These findings reflect the fact that primary keratinocytes express PD-L1 when stimulated by interferon-γ in vitro. When co-cu...
Source: Journal of Autoimmunity - Category: Allergy & Immunology Authors: Tags: J Autoimmun Source Type: research