Home  About us  Contact
 

Peripheral NK Cells (peripheral + nk_cell)

Distribution by Scientific Domains
Medical Sciences100%

Selected Abstracts

Increased natural cytotoxicity receptor expression and relevant IL-10 production in NK cells from chronically infected viremic HCV patients

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2007
Andrea De Maria M. D.
Abstract Hepatitis C virus (HCV) readily establishes high-level lifelong persistent infection in the majority of immunocompetent adults with failure of HCV-specific CD8+ CTL to clear viral replication. Virus-induced conditioning of innate immune responses is a possible mechanism that may contribute to the impairment of virus-specific CD8+ CTL responses. Here, we analyzed whether triggering of NK cell receptor expression and function is affected during chronic viremic HCV infection. Flow cytometric analysis of purified resting peripheral NK cells showed no evidence of NK cell activation, while analysis of natural cytotoxicity receptors (NCR) showed that NK cells from HCV-infected patients had selective increased expression of NKp30 and NKp46. NK cells had corresponding conserved cytotoxic activity against all targets with the exception of HepG2 hepatoma cells. Freshly separated NK cells from HCV patients showed significant production of IL-10 and normal concentrations of IFN-, upon cell-mediated triggering. Thus, increased expression of NKp30 during HCV infection with increased IL-10 production could contribute, once NK cells localize in the liver, to a NK-DC crosstalk leading to skewing of subsequent adaptive immune responses and lack of virus control. [source]

Exogenous IL-15 in Combination With IL-15R, Rescues Natural Killer Cells From Apoptosis Induced by Chronic Alcohol Consumption

ALCOHOLISM, Issue 3 2009
Hui Zhang
Background:, Chronic alcohol consumption reduces the percentage and number of peripheral natural killer (NK) cells in mice and in humans. The underlying mechanism for these changes is only partly known. We recently found that chronic alcohol consumption inhibits NK cell release from the bone marrow (BM) and that this is associated with a decrease in splenic NK cells. The number of peripheral NK cells is tightly controlled by homeostatic proliferation. It is not known whether this mechanism is initiated in response to the reduction in splenic NK cells, or if so, why the steady state levels of NK cells are not restored. Methods:, To examine this mechanism, female C57BL/6 mice were given 20% w/v alcohol in the drinking water for 3 months. NK cell proliferation and apoptosis were determined before and after treatment with IL-15 alone or combined with its alpha receptor. Results:, Chronic alcohol consumption invoked homeostatic proliferation of splenic NK cells in an attempt to return NK cells to normal levels; however, this did not happen due to enhanced apoptosis of NK cells relative to proliferation. Chronic alcohol consumption decreased IL-15 producing cells in the spleen but not in the BM. The numbers of NK cells in the alcohol-consuming mice returned to normal levels in the spleen and were higher than normal in the BM after 2 daily injections of IL-15; however, the enhanced rate of apoptosis due to alcohol consumption was not decreased in the spleen or BM. Combined IL-15 and IL-15R, treatment decreased apoptosis of NK cells from alcohol-consuming mice to levels similar to untreated water-drinking mice and greatly increased the percentage and number of NK cells in both the spleen and BM. Conclusion:, Chronic alcohol consumption causes a self-unrecoverable loss of NK cells in the spleen by compromising NK cell release from the BM and enhancing splenic NK cell apoptosis that can be reversed with IL-15/IL-15R, treatment. [source]

The effects of phototherapy on the numbers of circulating natural killer cells and T lymphocytes in psoriasis

PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 2 2009
A. M. Tobin
The innate immune system is believed to be important in the pathogenesis of psoriasis and natural killer (NK) have been found in increased numbers in psoriatic plaques. Alterations in the numbers of NK cells in peripheral blood have been reported. We investigated the effect of phototherapy on levels of peripheral NK cells and lymphocytes in patients with psoriasis. In nine patients whom we followed before, during and after narrowband ultraviolet B (UVB) treatment there were no differences in the numbers of circulating lymphocytes, lymphocyte subsets or cells expressing NK markers and controls. Treatment with narrowband UVB did, however, significantly lower circulating CD4 counts which gradually recovered posttreatment. [source]

ORIGINAL ARTICLE: Women with Pre-Eclampsia Have an Altered NKG2A and NKG2C Receptor Expression on Peripheral Blood Natural Killer Cells

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2009
Nora Bachmayer
Problem, Preeclampsia, a pregnancy disorder, is associated with exaggerated inflammation and increased serum monokines. Uterine natural killer (NK) cells are implicated in preeclampsia pathology, but little is known regarding peripheral NK cells in the disease. Method of Study, We examined blood NK cells at delivery in women with preeclampsia, in healthy pregnant women and in healthy non-pregnant blood donors as a reference. Results, Although the percentages of both NKG2A- and NKG2C-positive NK cells were normal in preeclamptic women, the levels of NKG2A and NKG2C on NK cells were significantly up-regulated in these women. In vitro stimulation of PBMCs from healthy pregnant women and blood donors with monokines resulted in increased percentage of NKG2A+ NK cells and increased NKG2A levels, while levels of NKG2C were decreased. Conclusions, Our results suggest that the peripheral NK-cell pool is skewed in preeclampsia and possibly under the influence of monokines like interleukin (IL)-15 and IL-12. [source]