scholarly journals Natural killer (NK) cell activity during HIV infection: a decrease in NK activity is observed at the clonal level and is not restored after in vitro long-term culture of NK cells

2008 ◽  
Vol 90 (2) ◽  
pp. 181-187 ◽  
Author(s):  
D. SCOTT-ALGARA ◽  
F. VUILLIER ◽  
A. CAYOTA ◽  
G. DIGHIERO
Keyword(s):  
Hiv Infection ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Cell Activity ◽  
Nk Activity ◽  
Nk Cell Activity ◽  
Long Term Culture

scholarly journals Augmentation of Cytolytic Activity in Murine Natural Killer Cells and Inhibition of Tumor Growth by the Ethanol Fraction of Oyster Extract

2016 ◽  
Vol 17 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Kaito Sakaguchi ◽  
Ming Zhong ◽  
Saeko Kawai ◽  
Yoshio Shimizu ◽  
Eiichi Gohda
Keyword(s):  
Tumor Growth ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Cell Activity ◽  
Cytolytic Activity ◽  
Proteinase K ◽  
Nk Cell Activity

A reduced number and/or reduced activity of natural killer (NK) cells, which are important for defense against a variety of cancers and viral infections, occur under various stress conditions and in patients with various diseases. In this article, we report that the 30% to 50% ethanol precipitate of oyster extract (EPOE50) dose-dependently enhanced the activity of mouse spleen NK cells in vitro and in vivo. The activity of EPOE50 was eluted with a molecular weight of about 2000 by gel filtration and was inactivated by periodate but not by proteinase K. The activity of highly purified NK cells was also augmented by EPOE50 but not by oligodeoxyribonucleotide 1585, which mimics bacterial DNA. Administration of EPOE50 to mice stimulated splenic NK cell activity without a change in splenic NK cell populations. Although the proliferation of B16 tumor cells in vitro was slightly stimulated by EPOE50, the growth of B16 melanoma in vivo was dose-dependently suppressed by administration of EPOE50. Taken together, our results indicate that EPOE50 augmented NK cell activity and that its administration to mice inhibited tumor growth presumably through the activation of NK cells and also suggest that the active substance is a sugar-containing oligomer or polymer and is not of bacterial origin.

scholarly journals Effects of Bacillus firmus e volumine ex muris cellulae 6x on cytolytic activity of natural killer cells in vitro

2021 ◽  
Vol 20 (2-3) ◽  
pp. 34-43
Author(s):  
Dieter Sonntag ◽  
Stephan Sudowe
Keyword(s):  
Immune System ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Function ◽  
Nk Cell ◽  
Cell Activity ◽  
Bacillus Firmus ◽  
Nk Cell Activity ◽  
The Impact

Natural killer (NK) cells are among the first in defense of the innate immune system by eliminating a variety of abnormal or stressed cells such as cancer cells or virus-infected cells. Individuals who exhibit low cytolytic NK cell activity are believed to be at higher risk of viral infection, tumorigenesis, and various other diseases of the immune system. Therefore, restoration of impaired NK cell function might be an essential step in immunostimulatory therapy of immunocompromised patients. Bacillus firmus is a non-pathogenic gram-positive bacterium of the environment, which possesses various immunomodulatory properties in vitro and in vivo. This retrospective study reports on the effect of B. firmus on the activity of NK cells in vitro. Basal cytolytic NK cell activity against tumor cells among peripheral blood mononuclear cells (PBMCs) of routine patients was determined in a standardized NK cell cytotoxicity assay. The impact of cultivation of PBMCs with B. firmus preparation Bacillus firmus e volumine ex muris cellulae (Bacillus firmus (evc)) 6x on tumor cell killing by NK cells was monitored in relation to basal NK cell activity. This study showed that stimulation of PBMCs with Bacillus firmus (evc) 6x in vitro led to a significant increase in NK cell function. Substantial improvement in cytolytic NK cell activity (more than 1.3-fold of basal activity) was much more pronounced for patients with compromised NK cell function. Due to its immunostimulatory mode of action, Bacillus firmus (evc) may be of particular importance in therapy of patients with NK cell deficiency.

scholarly journals Normalized natural killer (NK) cell activity in long-term remission of acute leukaemia

1983 ◽  
Vol 55 (2) ◽  
pp. 305-309 ◽  
Author(s):  
Yasuhiro Yoda ◽  
Tsukasa Abe ◽  
Akio Tashiro ◽  
Shinsaku Hirosawa ◽  
Kenichi Kawada ◽  
...  
Keyword(s):  
Natural Killer ◽  
Acute Leukaemia ◽  
Nk Cell ◽  
Cell Activity ◽  
Nk Cell Activity

scholarly journals miR-1224 contributes to ischemic stroke-mediated natural killer cell dysfunction by targeting Sp1 signaling

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yan Feng ◽  
Yan Li ◽  
Ying Zhang ◽  
Bo-Hao Zhang ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Nk Cells ◽  
Natural Killer ◽  
Brain Ischemia ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Activity ◽  
Passive Transfer ◽  
Immune Defense ◽  
Nk Cell Activity

Abstract Background Brain ischemia compromises natural killer (NK) cell-mediated immune defenses by acting on neurogenic and intracellular pathways. Less is known about the posttranscriptional mechanisms that regulate NK cell activation and cytotoxicity after ischemic stroke. Methods Using a NanoString nCounter® miRNA array panel, we explored the microRNA (miRNA) profile of splenic NK cells in mice subjected to middle cerebral artery occlusion. Differential gene expression and function/pathway analysis were applied to investigate the main functions of predicted miRNA target genes. miR-1224 inhibitor/mimics transfection and passive transfer of NK cells were performed to confirm the impact of miR-1224 in NK cells after brain ischemia. Results We observed striking dysregulation of several miRNAs in response to ischemia. Among those miRNAs, miR-1224 markedly increased 3 days after ischemic stroke. Transfection of miR-1224 mimics into NK cells resulted in suppression of NK cell activity, while an miR-1224 inhibitor enhanced NK cell activity and cytotoxicity, especially in the periphery. Passive transfer of NK cells treated with an miR-1224 inhibitor prevented the accumulation of a bacterial burden in the lungs after ischemic stroke, suggesting an enhanced immune defense of NK cells. The transcription factor Sp1, which controls cytokine/chemokine release by NK cells at the transcriptional level, is a predicted target of miR-1224. The inhibitory effect of miR-1224 on NK cell activity was blocked in Sp1 knockout mice. Conclusions These findings indicate that miR-1224 may serve as a negative regulator of NK cell activation in an Sp1-dependent manner; this mechanism may be a novel target to prevent poststroke infection specifically in the periphery and preserve immune defense in the brain.

Thermal stresses reduce natural killer cell cytotoxicity

1995 ◽  
Vol 79 (3) ◽  
pp. 732-737 ◽  
Author(s):  
S. J. Won ◽  
M. T. Lin
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Target Cell ◽  
Nk Cell ◽  
Cell Activity ◽  
Cortisol Concentration ◽  
Target Cells ◽  
Nk Cell Activity ◽  
Colonic Temperature ◽  
Effector Target

The effects of different ambient temperatures (Ta) on the splenic natural killer (NK) cell activity, effector-target cell conjugation activity, and NK cell numbers were assessed in male inbred C3H/HeNCrj mice (7–10 wk old). The splenic NK cytotoxic activities were examined in a 4-h 51Cr release assay in mouse spleen cells that were obtained 1, 2, 4, 8, or 16 days after exposure to Ta of 22, 4, or 35 degrees C. The percentage of conjugating lymphocytes was calculated by counting the number of single lymphocytes bound to single target cells per 400 effector cells. The numbers of NK cells were expressed by the percentage of 5E6-positive cells. The 5E6 identifies only a subset of NK cells. It was found that the splenic NK cell activity, the effector-target cell conjugation activity, or the NK cell number began to fall 1 day after cold (Ta 4 degrees C) or heat (Ta 35 degrees C) stress. After a 16-day period of either cold or heat exposure, the fall in the splenic NK cell activity, the effector-target cell conjugation activity, or the number of 5E6-positive subsets of NK cells was still evident. Compared with those of the control group (Ta 22 degrees C), the cold-stressed mice had higher adrenal cortisol concentration and lower colonic temperature, whereas the heat-stressed animals had higher adrenal cortisol concentration and higher colonic temperature during a 16-day period of thermal exposure. However, neither cold nor heat stress affected both the body weight gain and the spleen weight in our mice.

scholarly journals Leukocyte Immunoglobulin-Like Receptor 1-Expressing Human Natural Killer Cell Subsets Differentially Recognize Isolates of Human Cytomegalovirus through the Viral Major Histocompatibility Complex Class I Homolog UL18

2016 ◽  
Vol 90 (6) ◽  
pp. 3123-3137 ◽  
Author(s):  
Kevin C. Chen ◽  
Richard J. Stanton ◽  
Jareer J. Banat ◽  
Mark R. Wills
Keyword(s):  
Immune Responses ◽  
Nk Cells ◽  
Natural Killer ◽  
Cytomegalovirus Infection ◽  
Hcmv Infection ◽  
Nk Cell ◽  
Long Term Memory ◽  
Term Memory

ABSTRACTImmune responses of natural killer (NK) cell are controlled by the balance between activating and inhibitory receptors, but the expression of these receptors varies between cells within an individual. Although NK cells are a component of the innate immune system, particular NK cell subsets expressing Ly49H are positively selected and increase in frequency in response to cytomegalovirus infection in mice. Recent evidence suggests that in humans certain NK subsets also have an increased frequency in the blood of human cytomegalovirus (HCMV)-infected individuals. However, whether these subsets differ in their capacity of direct control of HCMV-infected cells remains unclear. In this study, we developed a novelin vitroassay to assess whether human NK cell subsets have differential abilities to inhibit HCMV growth and dissemination. NK cells expressing or lacking NKG2C did not display any differences in controlling viral dissemination. However, whenin vitro-expanded NK cells were used, cells expressing or lacking the inhibitory receptor leukocyte immunoglobulin-like receptor 1 (LIR1) were differentially able to control dissemination. Surprisingly, the ability of LIR1+NK cells to control virus spread differed between HCMV viral strains, and this phenomenon was dependent on amino acid sequences within the viral ligand UL18. Together, the results here outline anin vitrotechnique to compare the long-term immune responses of different human NK cell subsets and suggest, for the first time, that phenotypically defined human NK cell subsets may differentially recognize HCMV infections.IMPORTANCEHCMV infection is ubiquitous in most populations; it is not cleared by the host after primary infection but persists for life. The innate and adaptive immune systems control the spread of virus, for which natural killer (NK) cells play a pivotal role. NK cells can respond to HCMV infection by rapid, short-term, nonspecific innate responses, but evidence from murine studies suggested that NK cells may display long-term, memory-like responses to murine cytomegalovirus infection. In this study, we developed a new assay that examines human NK cell subsets that have been suggested to play a long-term memory-like response to HCMV infection. We show that changes in an HCMV viral protein that interacts with an NK cell receptor can change the ability of NK cell subsets to control HCMV while the acquisition of another receptor has no effect on virus control.

NK Cell Activity Influences Long Term Outcome of Pediatric Leucemias After T Cell Depleted Stem Cell Transplantation,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4141-4141
Author(s):  
Peter Lang ◽  
Matthias Pfeiffer ◽  
Heiko-Manuel Teltschik ◽  
Paul G. Schlegel ◽  
Tobias F. Feuchtinger ◽  
...  
Keyword(s):  
Stem Cell ◽  
T Cell ◽  
Relapse Rate ◽  
Nk Cell ◽  
Cell Activity ◽  
Nk Activity ◽  
Nk Cell Activity ◽  
Cell Recovery ◽  
Magnetic Microbeads

Abstract Abstract 4141 T cell depletion with magnetic microbeads can effectively reduce GvHD rates after stem cell transplantation from both mismatched related donors as well as from matched or partially matched unrelated donors. However, T cell recovery is markedly delayed after this procedure and T cell mediated antileukemic effects may be reduced. Thus, we focused on the rapidly regenerating donor derived NK cell system and addressed the question, whether its functional activity would influence the probability of relapse in a long term analysis. Temporal development of NK cell activity was monitored in 47 pediatric patients with leukemias (ALL, AML, CML, JMML) and myelodysplastic syndromes after transplantation of T cell depleted stem cells from matched unrelated (n=18) and mismatched related (haploidentical, n=29) donors with a median follow up of 7.4 years (2.1–12). 38 patients had CR1-3, 9 patients had active disease at time of transplantation. EFS and relapse rate at 5 years for the entire group were 36% and 40%, respectively (EFS and relapse rate for ALL patients in CR1-3: 50% and 36%; EFS and relapse rate for AML/MDS patients: 22% and 30%). CD34+ selection with magnetic microbeads resulted in 8×103/kg residual T cells. No posttransplant immune suppression was given. 89% of the patients had no GvHD, 9% had GvHD grade I and only 2 patients had GvHD grade II or III. NK cells recovered rapidly after transplantation (300 CD56+/μL at day 30, median), whereas T cell recovery was delayed (median: 12 CD3+/μL at day 90). NK activity was measured as specific lysis of K562 targets several times after transplantation (mean: 3 assays per patient). Four temporal patterns of lytic activity could be differentiated: consistently low, consistently high, decreasing and increasing activity. Patients with consistently high or increasing activity had significantly lower relapse probability than patients with consistently low or decreasing levels (0.18 vs 0.73 at 5 years, p<0.05). The subgroup of patients with ALL showed similar results (0.75 vs 0.14 at 5 years, p<0.05). Speed of T cell recovery had no influence. These data suggest that both achieving and maintaining a high level of NK activity may contribute to prevent relapse. Thus, this model comprises direct functional data in the form of NK cell activation levels which are likely to be influenced by the presence of different cytokines in each patient. Our observations may have some clinical implications: immunomagnetic depletion of T cells prevents GvHD and can be performed in pediatric leukemias in remission without excessive increase in relapse rates. High levels of NK activity seem to be of importance. Since NK activity could be markedly increased by in vitro stimulation with Interleukin 2 (IL-2), in vivo administration should be considered. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Patients with a deficiency of natural killer cell activity lack the VEP13-positive lymphocyte subpopulation

Blood ◽  
1985 ◽  
Vol 65 (1) ◽  
pp. 65-70 ◽  
Author(s):  
HW Ziegler-Heitbrock ◽  
H Rumpold ◽  
D Kraft ◽  
C Wagenpfeil ◽  
R Munker ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Natural Killer Cell Activity ◽  
Killer Cell ◽  
Cell Activity ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Target Cells ◽  
Nk Cell Activity

Many patients with B-type chronic lymphocytic leukemia (CLL) exhibit a profound defect in their natural killer (NK) cell activity, the basis of which is still obscure. Hence, we analyzed the NK cells from peripheral blood samples from 11 patients with CLL for phenotype and function, after removal of the leukemic cells with a monoclonal antibody (BA-1) plus complement. Phenotypic analysis of these nonleukemic cells with monoclonal antibodies (MoAbs) against NK cells revealed that the CLL patients had higher percentages of HNK-1-positive cells (23.5% compared to controls with 14.7%). In contrast, VEP13- positive cells were absent or low in seven patients (0.8% compared to controls with 11.2%) and normal in four patients (10.5%). When testing NK cell activities against K562 or MOLT 4 target cells, patients with no or minimal numbers of VEP13-positive cells were found to be deficient, while patients with normal percentages of VEP13-positive cells had NK cell activity comparable to controls. Isolation by fluorescence-activated cell sorter of HNK-1-positive cells from patients lacking VEP13-positive cells and NK cell activity indicated that the majority of the HNK-1-positive cells in these patients had the large granular lymphocyte morphology that is characteristic of NK cells. Thus, the deficiency of NK cell activity in CLL patients appears to result from the absence of cells carrying the VEP13 marker.

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