TYRP1 and graft versus host disease: NK1.1+ cells have been shown to contribute to antitumor immunity in some models.24,26,27 In others, they have been observed to prevent autoimmunity, GVHD, and tumor immunity, and cause chronic exhaustion of T cells.30-36 Since tyrosinase related protein-1 (TRP-1) is a TAA and depletion of NK1.1+ cells leads to enhanced autoimmunity and increased T cell activity, we investigated the possibility that pre-mNK cells could be preventing antitumor immunity in our model.