Cytokine release of human NK cells solely triggered with Poly I:C

Natural killer (NK) cells play a crucial role in innate immunity as effectors against tumor cells and pathogen-infected cells. Our data show for the first time that NK cells produce high levels of cytokines interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in response to stimulation with the artificial RNA analogue Poly I:C without additional cytokines or contact to other types of immune cells. An incubation period of 48 h is necessary to induce cytokine release by Poly I:C. These data suggest Poly I:C as a competent direct activator and immunomodulator of NK cell functions.