• Parasites, Hosts and Diseases
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• v.29 no.3
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• pp.267-278
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• 1991

The natural killer (NK) cell activity of splenocytes and recycling capacity of NK cells were observed by combining the $^{51}Cr-release$ cytotoxicity assay and single cell cytotoxicity assay against YAC-1. The ICR mice were infected intranasally with Naegleria fewleri, that is a pathogenic free-living amoeba. The mice infected with $1{\times}10^5$ trophosoites showed mortality rate of 76.7% and mean survival time of 12. 9 days. The cytotoxic activity of NK cells in infected mice was significantly higher than that of non-infected mice during the period between 12 hours and day 3 after infection, and highest on day 1. The target-binding capacity of NK cells in infected mice was not different from that of non-infected ones. Maximal killing potential and maximal recycling capacity were remarkably increased in infected mice as compared with the control. The results obtained in this observation indicated that elevated NK cell activity in mice infected with N. fowieri was not due to target-binding capacity of NK cells but due to the increased activity of NK cells and increased recycling capacity of individual NK cells.

• The Journal of Korean Medicine
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• v.26 no.4
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• pp.46-55
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• 2005

Objectives: This experimental study was carried out to evaluate the immune modulating and anti-tumor activity of Ampelopsis Radix extracts (ARE). Materials and Methods: To elucidate the effects of ARE on the macrophage and NK cell activity, we analyzed NO production, NK cytotoxicity and gene expressions of cytokine related with macrophage and NK cell activity. Results: ARE activated and promoted macrophages to product NO in part. And, ARE has significant properties to activate macrophages and NK cells by promoting related cytokines like IL-1, IL-12, IFN-$\gamma$, iNOS and TNF-$\alpha$ gene expressions. We also observed that ARE promoted protein expression of IFN-$\gamma$, and TNF-$\alpha$ in mice splenocytes. Conclusions: ARE is an effective herbal drug for immune modulating and anti-cancer by promoting activity of macrophages and NK cells.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.96-104
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• 2003

Ginger (Zingiber officinale Roscoe) is traditionally used as appetite enhancer, improver of the digestive system, antithusive, anti-cold, antipyretic, analgesic, and antiinflammation. In vitro evaluation using human lymphocyte cultures showed almost similar indication with those in in vivo mouse study, NK cell lysing activity was improved significantly. Proliferation activity of B and T cells, and CD3$^{＋}$ and CD3$^{＋}$CD4$^{＋}$T cell subset were better observed using oleoresin or gingerol and shogaol fractions. Although there were higher activities in gingerol, the improvement was almost equal to that by oleoresin. Shogaol did not show better improvement except at higher concentration. It could be concluded that treatment with single bioactive compound, such as gingerol, did not show significant effects compared to oleoresin, the crude extract. In human study, involving healthy male adult, the improvement of NK cell lysing activity was again demonstrated and even more apparent. The mechanism involved in the protection seemed to be through the antioxidant activity of gingerol. However, other mechanism underlying the improvement of NK cell lysing activity must be involved since this improvement seemed to be specifically toward NK cell activity. Since NK cells ave specific for the elimination of virus-infected cell and mutated cells, this positive effect on the immune system are very interesting. This work has also scientifically proved that the traditional beliefs that ginger had preventive effects on common cold appeared to be reasonable.

• Journal of Haehwa Medicine
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• v.21 no.1
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• pp.87-96
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• 2012

Aim : Natural killer (NK) cells are cytotoxic lymphocytes that lyse certain tumor- and virus-infected cells without any prior stimulation or immunization. This article aims to review the significance of evaluating peripheral blood NK cells to predict anti-tumor immune function and prognosis in cancer patients. Methods : PubMed was used to create a database for this review. Search words of cancer, natural killer cell, prognosis were used to retrieve related articles. References of the collected articles were also reviewed. Results : Current evidence indicates that decreased or absent NK cell count or activity is mostly associated with the development or progression of cancer. In patients with various types of cancer, NK cell activity was mostly associated with the cancer prognosis and survival despite some conflicting results. Conclusion : The data shows the evaluation of anti-tumor immunity in cancer patients through natural killer cell measurement still remains a controversial matter. However, it is clear that the NK cell activity plays an important role in cancer and is associated with prevention of both early stage and metastatic cancer.

• Journal of Ginseng Research
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• v.45 no.6
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• pp.695-705
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• 2021

Background: Ginsenosides have beneficial effects on several airway inflammatory disorders primarily through glucocorticosteroid-like anti-inflammatory activity. Among inflammatory cells, eosinophils play a major pathogenic role in conferring a risk of severe refractory diseases including chronic rhinosinusitis (CRS). However, the role of ginsenosides in reducing eosinophilic inflammation and CRS pathogenesis is unexplored. Methods: We investigated the therapeutic efficacy and underlying mechanism of ginsenoside F1 (G-F1) in comparison with those of dexamethasone, a representative glucocorticosteroid, in a murine model of CRS. The effects of G-F1 or dexamethasone on sinonasal abnormalities and infiltration of eosinophils and mast cells were evaluated by histological analyses. The changes in inflammatory cytokine levels in sinonasal tissues, macrophages, and NK cells were assessed by qPCR, ELISA, and immunohistochemistry. Results: We found that G-F1 significantly attenuated eosinophilic inflammation, mast cell infiltration, epithelial hyperplasia, and mucosal thickening in the sinonasal mucosa of CRS mice. Moreover, G-F1 reduced the expression of IL-4 and IL-13, as well as hematopoietic prostaglandin D synthase required for prostaglandin D2 production. This therapeutic efficacy was associated with increased NK cell function, without suppression of macrophage inflammatory responses. In comparison, dexamethasone potently suppressed macrophage activation. NK cell depletion nullified the therapeutic effects of G-F1, but not dexamethasone, in CRS mice, supporting a causal link between G-F1 and NK cell activity. Conclusion: Our results suggest that potentiating NK cell activity, for example with G-F1, is a promising strategy for resolving eosinophilic inflammation in CRS.

• Biomedical Science Letters
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• v.29 no.3
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• pp.178-183
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• 2023

Natural killer (NK) cells are innate cytotoxic lymphoid cells that actively prevent neoplastic development, growth, and metastatic dissemination in a process called cancer immunosurveillance. Regulation of the cytotoxic activity of NK cells relies on integrated interactions between inhibitory receptors and numerous activating receptors that act in tandem to eliminate tumor cells efficiently. Conventional chemotherapy is designed to produce an anti-proliferative or cytotoxic effect on early tumor cell division. Therapies designed to kill cancer cells and simultaneously maintain host anti-tumor immunity are attractive strategies for controlling tumor growth. Depending on the drug and dose used, several chemotherapeutic agents cause DNA damage and cancer cell death through apoptosis, immunogenic cell death, or other forms of non-killing (i.e., mitotic catastrophe, senescence, autophagy). Among stress-induced immunostimulatory proteins, changes in the expression levels of NK cell activating and inhibitory ligands and tumor cell death receptors play an important role in the detection and elimination by innate immune effectors including NK cells. Therefore, we will address how these cytotoxic lymphocytes sense and respond to high and low concentrations of drug-induced stress to the drug cisplatin, among the various types of drugs that contribute to their anticancer activity.

• Journal of Nutrition and Health
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• v.26 no.4
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• pp.379-389
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• 1993

Several studies have shown that extracts from yellow-green vegetables reveal antitumor activities. In the present study we investigated the effect of phytol in order to elucidate the immunological mechanism of antitumor activity of this substance. The results obtained from the experiment as follows: 1) Phytol showed cytotoxic effect on sarcoma 180 cells in vitro. 2) When phytol was injected into the peritoneal cavity of mice transplanted with sarcoma 180 cells, the average survival time (24.0 days) tended to increase as compared with the nontreated control (19.2 days). 3) When sarcoma 180 cells were injected subcutaneously into the right groin of mice, and then phytol was injected into the peritoneal cavity, the tumor inhibition ratio was 33%. 4) The natural killer(NK) cell activity was significantly augmented by phytol in vitro and in vivo. Similar augmentations of NK cell activity were obtained with culture supernatants of phytol exposed spleen cells and peripheral blood mononuiclear cells. 5) Phytol on the macrophage from peritoneal cavity showed a higher effectiveness in vivo than in vitro. These results indicate that phytol shows the inhibitory effect for growth of sarcoma 180 cells in vitro, also it can augment macrophage and NK cell activities in vivo.

• Journal of Ginseng Research
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• v.48 no.3
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• pp.341-345
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• 2024

The objective of the study is to estimate the potential of gintonin, as an immune enhancing agent through natural killer cell (NK cell) activity in cyclophosphamide (CY)-induced immunosuppressive animals. Accumulated results reveals that, gintonin attenuated CY-induced immunosuppression and it might modulate NK cell activity to boost the immunity.

• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.717-719
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• 2006

A randomized, double blind, placebo-controlled human intervention study involving 62 healthy volunteers was performed to investigate the effects of Keumsa sangwhang (Phellinus linteus) mushroom extracts (KPLE) on natural killer (NK) cell activity in peripheral blood. The volunteers were randomly distributed into two groups, one receiving KPLE (3.3 g/day) and the other a placebo by oral administration for 8 weeks. In this study, the number of NK cells did not increase with KPLE administration, however the cytotoxic activity of NK cells against the Jurkat leukemia cell line increased significantly. This result suggests that administration of KPLE induces cell-mediated immunity by increasing NK cell activity in humans.

• Journal of Naturopathy
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• v.7 no.2
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• pp.63-69
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• 2018

Purpose: The purpose of this study was to investigate the effects of Bacillus fermentation broth (ENM) on the human NK cell activity, and bone matrix density, matrix content and area of hamsters fed ENM. Methods: NK cell activity was tested, and bone mineral density were measured by x-ray. Results: NK cell activity was significantly higher in the control group (644.71 pg/ml) and in the test group (1796.37 pg/ml) (p<.004). Test groups were significantly increased by 1110.37 pg/ml in the pre-test and 1796.37 pg/ml in the post-test(p<.001). Behavioral observations after feeding ENM to hamsters showed normal behavior with no difference between control and test groups. The hamster body weight of the control was 106 g at the initial and final 27 days. In the test group, the initial weight was 96.6 g and the final 27 days was 114 g. No morphological changes were observed in the X-ray photographs of the hamster hind legs. The bone matrix density was 0.059 g/cm³ in control and 0.062 g/cm³ in the test, which was increased by 0.003 g/cm³. The bone matrix content was 0.175 g in the control and 0.196 g in the test. The bone area was 2.95 cm² in the control and 3.19 cm² in the test, which was increased by 0.19 cm². In the autopsy, neither the control nor the test group showed any remarkable abnormality, and each organ was normal. Conclusions: It is thought that ingestion of ENM is useful for immunity enhancement.