Natural killer (NK) cells kill virus-infected or cancer cells through the release of cytotoxic granules into a tight intercellular contact. NK cell populations comprise individual cells with varying sensitivity to distinct input signals, leading to disparate responses. To resolve this NK cell heterogeneity, we have designed a novel assay based on ultrasound-assisted cell-cell aggregation in a m...

NK cells are required for early control of murine CMV (MCMV) infection, but the distribution of murine NK cells in situ has not been clearly defined. We tested the reactivity of all available NK cell receptor-specific mAbs by immunohistochemistry. Only one mAb, 4D11 (anti-Ly-49G2), was reactive with C57BL/6 tissue sections. mAb 4D11-reactive cells expressed the nuclear morphology and flow cytom...

Natural killer (NK) cells are important innate immune cells that can directly kill transformed or virus-infected cells. The adoptive transfer of NK cells has been used to treat hematological malignancies; however, the limited sources and quantities of NK cells have restricted their clinical application. Here, we acquired sufficient quantities of functional NK cells from CD34+ cells treated with...

Because NK cells secrete cytotoxic granules and cytokines that can destroy surrounding cells and help shape the subsequent immune response, they must be kept under tight control. Several mechanisms, at different levels, are in place to control NK cell function. In this study, we describe a novel mechanism regulating NK cell function in which NK cells acquire ligands for activating receptors fro...

Trail(+)DX5(-)Eomes(-) natural killer (NK) cells arise in the mouse fetal liver and persist in the adult liver. Their relationships with Trail(-)DX5(+) NK cells remain controversial. We generated a novel Eomes-GFP reporter murine model to address this question. We found that Eomes(-) NK cells are not precursors of classical Eomes(+) NK cells but rather constitute a distinct lineage of innate ly...

Natural killer (NK) cells kill infected and tumor cells and produce cytokines that modulate other immune cells. However, most of our current knowledge is derived from investigations of mouse splenic and human peripheral blood NK cells, "conventional" NK cells. Herein we discuss recent studies indicating that the liver contains two subpopulations of NK cells, one of which is liver-resident and b...

Natural killer (NK) cells are known to be activated by Th1-type cytokines, such as IL-2, -12, or -18, and they secrete a large amount of IFN-γ that accelerates Th1-type responses. However, the roles of NK cells in Th2-type responses have remained unclear. Because IL-4 acts as an initiator of Th2-type responses, we examined the characteristics of NK cells in mice overexpressing IL-4. In this stu...

In mice lacking IL-15, NK cell development is arrested at immature stages, providing an opportunity to investigate the earliest developing NK cells that would respond to IL-15. We show in this study that immature NK cells were present in the spleen as well as bone marrow (BM) and contained IL-15-high-responder cells. Thus, mature NK cells were generated more efficiently from IL-15(-/-) than fro...

Hepatic natural killer (NK) cells are located in the liver sinusoids adherent to the endothelium. Human and rat hepatic NK cells induce cytolysis in tumor cells that are resistant to splenic or blood NK cells. To investigate the mechanism of cell death, we examined the capacity of isolated, pure (90%) rat hepatic NK cells to kill the splenic/blood NK-resistant mastocytoma cell line P815. Cell d...

BACKGROUND FcRγ-deficient natural killer (NK) cells (g(-)NK cells) have been associated with cytomegalovirus (CMV) infection. However, the frequency of g(-)NK cells in a CMV-endemic area (i.e., Korea) has not yet been studied. We examined the frequency of g(-)NK cells and expression of CD57 on NK cells in cord blood (CB) and adult blood (AB). METHODS Of the 24 AB samples collected, 95.8% (23/...