NK1.1 / CD161bc (also known as NKRP1, Ly55c, or Ly59) is a cell surface antigen expressed on NK cells and NK-T cells of certain mouse strains, which is being used for identification or antibody-mediated depletion of these cells in the respective strains. This antigen participates in NK cell activation, including production of interferon gamma, and release of cytotoxic granules.