Engagement of NK receptor NKG2D, but not 2B4, results in self-reactive CD8+T cells and autoimmune vitiligo

In this study, we demonstrate that engagement of two different natural killer receptors (NKRs) can lead to contrasting effects in the development of self-reactive CD8+T cells and autoimmune vitiligo. Specifically, using a mouse model, we show that CD8+T-cell targeting of a melanocyte antigen, tyrosinase-related protein-1 (TRP-1) in combination with delivery of the NKG2D ligands (Rae-1ε or H60), results in strong CD8+T-cell responses against TRP-1 and in the development of autoimmune vitiligo. In contrast, targeting of TRP-1 in combination with delivery of CD48, the natural ligand for the NKR 2B4, leads to reduced formation of TRP-1-reactive CD8+T-cell responses and decreased development of vitiligo. These data indicate that autoimmune vitiligo is limited by insufficient signals, despite plentiful self-reactive T cells in the peripheral immune system. To our knowledge, this is the first experimental evidence supporting the role of NKRs in modulating CD8+T-cell autoimmune vitiligo. This study supports the utilization of NKR signaling as a therapeutic avenue toward prevention of vitiligo and other autoimmune diseases.