CD27-mediated activation of murine NK cells

CD27, a member of the TNF receptor superfamily, has been implicated in T ce ll activation, T cell development, and T cell-dependent Ab production by B cells. In the present study we examined the expression and function of CD27 on murine NK cells. Murine NK cells constitutively expressed CD27 on their surface. Stimulation with immobilized anti-CD27 mAb or murine CD27 ligand (CD70) transfectans solely could induce proliferation and IFN-gamma product ion of freshly isolated NK cells and enhanced the proliferation and IFN-gam ma production of anti-NK1.1-sutimulated NK cells. Although NK cell cytotoxi city was not triggered by anti-CD27 mAb or against CD70 transfectants, pres timulation via CD27 enhanced the cytotoxic activity of NK cells in an IFN-g amma-dependent manner. These results suggest that CD27-mediated activation may be involved in the NK cell-mediated innate immunity against virus-infec ted or transformed cells expressing CD70.