Highly purified populations of lymphocytes were obtained from the murine intestinal mucosa using EDTA-collagenase isolation procedures in combination with discontinuous density centrifugation. Intraepithelial lymphocytes (IEL) were separated from lamina propria lymphocytes (LPL) and, within these two populations, fractions enriched or depleted in gut granular lymphocytes (gGL) were obtained. Us...

Studies of chemokine receptors (CKR) in natural killer- (NK-) cells have already been published, but only a few gave detailed information on its differential expression on blood NK-cell subsets. We report on the expression of the inflammatory and homeostatic CKR on normal blood CD56(+low) CD16(+) and CD56(+high)  CD16(-/+low) NK-cells. Conventional CD56(+low) and CD56(+high) NK-cells present in...

Natural killer (NK) cells have innate antibacterial activity that could be targeted for clinical interventions for infectious disease caused by naturally occurring or weaponized bacterial pathogens. To determine a potential role for NK cells in immunity to Bacillus anthracis, we utilized primary human and murine NK cells, in vitro assays, and in vivo NK cell depletion in a murine model of inhal...

Dendritic cells (DC) play a key role in establishing protective adaptive immunity in intracellular bacterial infections, but the cells influencing DC function in vivo remain unclear. In this study, we investigated the role of NK cells in modulating the function of DC using a murine Chlamydia infection model. We found that the NK cell-depleted mice showed exacerbated disease after respiratory tr...

Natural killer (NK) cells are critical in eliminating tumors and viral infections, both of which occur at a high incidence in the elderly. Previous studies showed that aged NK cells are less cytotoxic and exhibit impaired maturation compared to young NK cells. We evaluated whether extrinsic or intrinsic factors were responsible for the impaired maturation and function of NK cells in aging and w...

Previously, we showed that 2B4 is a dominant inhibitory receptor in SHIP-deficient NK cells that prevents efficient cytolysis of complex targets. We show in this study that 2B4 deficiency restores homeostatic control and cytolytic function to SHIP-deficient NK cells. However, 2B4(-/-)SHIP(-/-) NK cells still exhibit a profound disruption of their NK receptor repertoire and are compromised for i...

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/...

The mechanisms for NK cell activation during infection by intracellular bacterial pathogens are not clearly defined. To dissect how Listeria monocytogenes infection elicits NK cell activation, we evaluated the requirements for activation of naive splenic NK cells by infected bone marrow-derived dendritic cells (BMDCs). We found that NK cell activation in this setting required infection of BMDCs...

Natural killer (NK) cells contribute to not only innate but also to adaptive immunity by interacting with dendritic cells (DCs) and T cells. All activated human NK cells express HLA-DR and can initiate MHCII-dependent CD4(+) T-cell proliferation; however, the expression of MHCII by mouse NK cells and its functional significance are controversial. In this study, we show that NK-DC interactions r...

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...