NK-1.1 surface antigen is encoded by the NKR-P1B/NKR-P1C gene, also known as CD161b/CD161c and Ly-55. It is expressed on NK cells and NK-T cells in some mouse strains, including C57BL/6, FVB/N, and NZB, but not AKR, BALB/c, CBA/J, C3H, DBA/1, DBA/2, NOD, SJL, and 129. Expression of NKR-P1C antigen has been correlated with lysis of tumor cells in vitro and rejection of bone marrow allografts in vivo. NK-1.1 has also been shown to play a role in NK cell activation, IFN- gamma production, and cytotoxic granule release. NK-1.1 and DX5 are commonly used as mouse NK cell markers. The PK136 antibody has been reported to deplete NK cells, induce redirected lysis, block NK cell function, and induce NK cell proliferation.
