We have recently shown that Natural Killer (NK) cells control survival and differentiation of Cancer Stem-like Cells (CSCs) through two distinct phenotypes of cytotoxic and anergic NK cells, respectively. In this report, brain CSCs and their serum and NK cell differentiated counterparts were studied. Serum-differentiated brain CSCs were significantly less susceptible to NK cells and CTL direct ...

Natural killer (NK) cells are critical innate immune lymphocytes capable of destroying virally infected or cancerous cells through targeted cytotoxicity and further assisting in the immune response by releasing inflammatory cytokines. NK cells are thought to contribute to the process of tumor killing by certain therapeutic monoclonal antibodies (mAb) by directing antibody-dependent cellular cyt...

Natural killer (NK) cells are innate effector lymphocytes that control the growth of major histocompatibility complex class I negative tumors. We show here that T lymphocytes, expanded in vitro in the presence isopentenylpyrophosphate (IPP), induce NK cell–mediated killing of tumors that are usually resistant to NK cytolysis. The induction of cytotoxicity toward these resistant tumors requires ...

Perforin (Prf1) and granzyme B (GzmB) are essential effector molecules for natural killer (NK)-cell cytotoxicity, but how Prf1 and GzmB expression is regulated during arming of NK cells is poorly defined. We show that human microRNA (miR)-27a* is a negative regulator of NK-cell cytotoxicity by silencing Prf1 and GzmB expression. Human miR-27a* specifically bound to the 3' untranslated regions o...

Myelodysplastic syndromes (MDS) are clonal stem cell disorders characterized by ineffective hematopoiesis that lead to leukemia. Disorders of the immune system serve important functions in the pathophysiology and progression of this disease. Different levels or mechanisms of natural killer (NK) cells in patients with MDS have been measured in previous studies, making it challenging to understan...

We examined the relationship between natural killer (NK) cell-mediated cytotoxicity, the produced active-oxygen and cytotoxic factor (CF) release in co-culturing canine NK cells with tumor cells (CL-1 target cells). In co-culturing, the adding of n-propyl gallate (active-oxide scavenger) removed the produced active-oxygen, which inhibited NK cell-mediated cytotoxicity and the CF release. Moreov...

The spontaneous natural killer (NK) and lymphokine-activated killer (LAK) cytotoxicity of highly purified CD56+CD3- NK cells (90 to 95%) against NK-sensitive and NK-insensitive target cells was drastically enhanced when a rhamnogalacturonan contained in a commercially available Viscum album extract was present during 4-h cytotoxicity assays. This enhancement correlated strictly with an increase...

Natural killer (NK) cells directly lyse tumor or viral-infected cells but also an important role for NK cell cytotoxicity in regulating the extent of immune responses is emerging. Here, we show that autologous human macrophages activated NK cell proliferation and cytokine secretion, increased expression of activating receptors, and primed NK cell cytotoxicity against susceptible target cells. L...

The aim of the present study was to investigate the effects of Ginseng polysaccharides (GPS) on natural killer (NK) cell cytotoxicity in immunosuppressed mice. Cyclophosphamide (Cy) was used to construct an immunosuppressed mouse model. The mice in each group were submitted to gavages with 200 or 400 mg/kg GPS every day for 10 days. Magnetic-activated cell sorting was used to isolate spleen NK ...