• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1035-1043
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• 1999

Bacteriocins are natural antimicrobial compounds produced by many microorganisms associated with foods, so that there is currently much interest in their use as food biopreservatives. Goal of this study was to partially evaluate lacticin NK24 as a food biopreservative by showing antimicrobial activity of L. lactis NK24 and lacticin NK24 against food-borne spoilage and pathogenic bacteria, respectively. Lactic acid bacteria NK24 isolated from jeot-gal, Korean fermented fish foods, was tentatively identified as Lactococcus lactis and showed broad spectrum of activity against all of spoilage and pathogenic bacteria tested by deferred method. Bacteriocin production in jar fermenter was detected at the mid-log growth phase, and reached the maximum at the early stationary phase, but decreased after the stationary phase. Lacticin NK24 was partially purified by 75% ammonium sulfate precipitation followed by subsequent dialysis. This partially purified lacticin NK24 showed antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Clostridium perfringens, some bacilli, Listeria monocytogenes, Listeria ivanovii, Sphin-gomonas pausimobilis, Escherichia coli and Pseudomonas aeruginosa. Thus, lacticin NK24 examined in this study show promise as a biopreservative be-cause of their broad spectrum of activity.

• Korean Journal of Food Science and Technology
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• v.44 no.4
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• pp.488-492
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• 2012

Two strains, traditionally referred to as rock flower (Bawhi-kot) and buckwheat flower (Memil-kot or Chile-Kot), were isolated from stored traditional soy sauce and were identified by using the 18S ITS1/4 region sequences. The rock flower strain showed 99% of similarity with Cladosporium sp. and buckwheat flower strain was 99% identical with yeast Sterigmatomyces halophilus. Both strains were tentatively named Cladosporium sp. NK1 and Sterigmatomyces halophilus NK2, respectively. The optimal growth pHs and temperatures of both strains in a YPD broth medium were in the range of pH 5.0 to 7.0 and 22 to $27^{\circ}C$. Both strains were able to grow in more than 20% of NaCl. In the enzyme activity assay, high protease activity of Cladosporium sp. NK1 and S. halophilus NK2 were obtained in YPD containing 10% of NaCl. High amylase activities of both stains were in 15% and 5% of NaCl, respectively. Lipase activity was, however, not detected in both strains.

• The Korean Journal of Pain
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• v.31 no.1
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• pp.43-49
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• 2018

Background: Chronic pain reportedly exerts complex effects on immune function. Natural killer (NK) cells are lymphocytes that play a critical role in cellular and innate immunity. This study examined changes in the subset populations and cytotoxic activity of peripheral blood NK cells in patients with chronic pain. Methods: Thirty patients with chronic moderate-to-severe pain (group P) and age-matched pain-free subjects (group NoP) were enrolled. Peripheral whole blood was analyzed for the percentage and expression of NK cell surface markers (CD56 and CD16) by flow cytometry. Cytotoxic activity was assayed by evaluating CD69 expression on $CD3^-/CD56^+NK$ cells. Results: The percentage of NK cells among total lymphocytes was not significantly different between groups P and NoP ($16.3{\pm}9.3$ vs. $20.2{\pm}10.5%$). Likewise, the percentages of two major NK cell subsets, $CD56^{bright}$ and $CD56^{dim}$, were also not significantly different between the two groups. However, the percentage of $CD56^{bright}/CD16^+$ subset, was slightly but significantly increased in group P ($1.0{\pm}0.9%$; P< 0.01) compared with group NoP ($0.5{\pm}0.6%$). The cytotoxicity of NK cells was not different between the two groups, showing similar CD69 expression (P vs. $NoP=29.2{\pm}15.2$ vs. $32.0{\pm}15.0%$). These findings were not influenced by pain intensity, opioid use, or disease causing pain in group P. Conclusions: NK cell cytotoxic activity and major subset populations, with the exception of an increased percentage of the $CD56^{bright}/CD16^+$ subset, are not significantly altered in patients with chronic severe pain.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.995-1000
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• 2004

This study was purposed to investigate the effect of Gamgung-tang(GGT) on immune responses induced by glucocorticoid in mice. GGT solution was treated by intraperitoneal injection for 7 days after glucocorticoid treatment(80㎎/㎏). And then B and T cell proliferation and cytolytic activity of natural killer(NK) cells were measured. There was 25% inhibition in B cell proliferation with treatment of glucocorticoid. However, B cell proliferation was not influenced by GGT treatment. T cell proliferation was also inhibited by 18.4% with treatment of glucocorticoid. On the other hand, T cell proliferation was increased dose-dependent manner in GGT treated group. Furthermore in purified T cell, the proliferation was furtherly increased than non-purified T cell. At concentration of 18㎎/mouse GGT, purified T cell proliferation was increase to above level of normal group. The cytotoxic activity of NK cell was decreased by 35.3% with treatment of glucocorticoid. In GGT treated group, the cytotoxic activity of NK cell was increased to the normal level. In purified NK cell, the cytolytic activity of NK cell was further increased than non-purifed NK cell. These results suggest that GGT may proliferate T cell that is suppressed by glucocorticoid, and activate NK cell activity.

• IMMUNE NETWORK
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• v.7 no.3
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• pp.133-140
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• 2007

Background: It is well established that cross talk between natural killer (NK) cells and myeloid dendritic cells (DC) leads to NK cell activation and DC maturation. In the present study, we investigated whether type 1-polarized DC (DC1) matured in the presence of IFN-${\gamma}$ and type 2-polarized DC (DC2) matured in the presence of PGE2 can differentially activate NK cells. Methods: In order to generate DC, plastic adherent monocytes were cultured in RPMI 1640 containing GM-CSF and IL-4. At day 6, maturation was induced by culturing the cells for 2 days with cytokines or PGE2 in the presence or absence of LPS. Each population of DC was cocultured with NK cells for 24 h. The antigen expression on DC was analyzed by flow cytometry and cytokine production in culture supernatant was measured by ELISA or a bioassay for TNF-${\alpha}$ determination. NK cell-mediated lysis was determined using a standard 4h chromium release assay. Results: DC2, unlike DC1, had weak, if any, ability to induce NK cell activation as measured by IFN-${\gamma}$ production and cytolytic activity. DC2 were weakly stimulated by activated NK cells compared to DC1. In addition, IFN-${\gamma}$-primed mature DC appeared to be most resistant to active NK cell-mediated lysis even at a high NK cell/DC ratio. On the other hand, PGE2-primed DC were less resistant to feedback regulation by NK cells than IFN-${\gamma}$-primed mature DC. Finally, we showed that the differential effect of two types of DC population on NK cell activity is not due to differences in their ability to form conjugates with NK cells. Conclusion: These results suggest that different combinations of inflammatory mediators differentially affect the effector function of DC and, as a result, the function of NK cells, eventually leading to distinct levels of activation in adaptive immunity.

• IMMUNE NETWORK
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• v.6 no.1
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• pp.6-12
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• 2006

Background: The Hypothalamo-Pituitary-Adrenal (HPA) axis is an important regulator for the body's stress response. As a primary stress responsive system, HPA-axis secretes various neurotransmitters, hormones, and cytokines, which regulates the immune system. Natural killer (NK) cell which is plays an important role in the innate immune response, is specially decreased their numbers and loose cytolytic activity in response to stress. However, the effect of HPA-axis secreted proteins on NK cell activity has not been defined. Herein, we studied the effect of adrenal secreted adiponectin on NK cell cytotoxicity. Adiponectin which is well-known metabolic control protein, plays important roles in various diseases, including hypertension, cardiovascular diseases, inflammatory disorders, and cancer. Methods: Signal sequence trap was used to find stress novel secretory protein from HP A-axis. Selected adiponectin was treated mouse mature primary NK cells and then examined the effect of adiponectin to NK cell cytotoxicity and cytokine expression level. Results: We found that adiponectin which is secreted from adrenal gland, suppress IL-2 induced NK cell cytotoxicity. And also investigated cytolytic cytokines are suppressed by adiponectin. Conclusion: These data suggest that adiponectin inhibites NK cell cytotoxicity via suppression of cytotoxicity related target gene.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1991.06a
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• pp.20-20
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• 1991

악성종양의 발생과 진행에 면역 방어기능이 중요한 역할을 하리라는 가설은 모두가 공감하는 사실이다. 이중 T-lymphocyte와 Natural killer cell (이하 NK cell이라함)은 종양 면역학에 특히 중요한 임파구로 이런 임파구의 혈액분포양상은 면역방어기능을 짐작할 수 있는 간접적인 자료가 될 수 있다. 저자들은 치료전 두경부 악성종양환자에서 혈액을 채취하여 T-lymphocyte와NK cell의 분포양상을 검사하고, 방사선치료 환자에서는 NK cell activity를 측정하였기에 다음과 같은 결과를 보고하는 바이다. 1) 두경부 악성 종양 환자군에서 CD3+ cell은 감소하고 NK cell은 증가하며 CD4/CD8 비율은 변화가 없었다. 2) 병변이 진행되면서 CD3+ cell과 CD4+ cell은 감소하고 NK cell은 증가하였으며 CD4/CD8 비율의 변화는 없었다. 3) 방사선치료에 의해 CD3+ cell과 CD4+ cell, CD4/CD8 비율은 감소하였고, NK cell과CD8+cell은 증가하였다. 4) 방사선치료에 의한 CD4/CD8 비율의 감소와, CD8+ cell의 증가는 NK cell의 증가에 의한 것이라 추정되고, NK cell을 제외하면 CB4/CD8 비율의 변화는 없었다. 5) 방사선치료 환자에서 NK cell activity는 증가하였고, 이런 증가가 T-lymphocyte기능의 감소를 보상해 주고 있었다.

• The Journal of Korean Medicine
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• v.25 no.4
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• pp.161-170
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• 2004

Objective : The purpose of this study was to investigate the effects of Armillaria mellea extract (AME) on immune modulation focused on anti-cancer activity. Methods : To prove the effects of AME, we performed NO assay, NK cytotoxicity assay and RT-PCR of cytokine related with macrophage and NK cell activity. Results : AME increased NO production produced by macrophages in part. AME also enhanced the NK cell activities in destroying target cells (YAC-1 cells). AME up-regulated gene expression of IL-l, iNOS, TNF-a in RAW 264.7 cells and IL-l, IL-2, IFN-(equation omitted), TNF-a in splenocytes, respectively. Conclusion : From the above results, we assumed that AME is a potential drug for anti-cancer by activation of the macrophages and NK cells.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.227-231
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• 2006

Strain NK181 was isolated for probiotic use from jeotkal and based on results of API 50 CHL kit and 16S rDNA sequencing was tentatively named Lactobacillus plantarum NK181. L. plantarum NK181 was highly resistant to artificial gastric juice (pH 2.5) and bile acid and demonstrated strong adherence to Caco-2 cells. In test using API ZYM kit, eight enzymes were produced. Supernatant of L. plantarum NK181 exhibited about 30% 1,1-diphenyl-2-picyryl hedrazyl (DPPH) radical-scavenging activity and reduced cholesterol by 70%. These results demonstrate potential use of L. plantarum NK181 as health-promoting probiotic.

• Nutrition Research and Practice
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• v.11 no.1
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• pp.43-50
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• 2017

BACKGROUND/OBJECTIVES: The present study investigated the hypothesis that a highly pure linear ${\beta}$-1,3-glucan produced by Agrobacterium sp. R259 enhances human natural killer (NK) cell activity and suppresses pro-inflammatory cytokines. SUBJECTS/METHODS: In an eight-week, double-blind, randomized, placebo-controlled clinical trial, 83 healthy adults with white blood cell counts of $4,000-8,000cells/{\mu}L$ were participated and randomly assigned to take two capsules per day containing either 350 mg ${\beta}$-1,3-glucan or placebo. Six participants withdrew their study consent or were excluded due to NK cell activity levels outside the normal range. NK cell activity and serum levels of immunoglobulin G (IgG) and cytokines, such as interferon (IFN)-${\gamma}$, interleukin (IL)-2, IL-4, IL-6, IL-10, IL-12 and tumor necrosis factor (TNF)-${\alpha}$ were measured. RESULTS: NK cell activity and the serum levels of IL-10 were significantly higher from baseline to week 8 in the ${\beta}$-glucan group compared with the placebo group (P = 0.048, P = 0.029). Consumption of ${\beta}$-1,3-glucan also significantly increased NK cell activity compared with placebo after adjusting for smoking and stress status (P = 0.009). In particular, the effect of ${\beta}$-1,3-glucan on NK cell activity was greater in participants with severe stress than in those experiencing mild stress. However, the administration ${\beta}$-1,3-glucan did not significantly modulate the levels of IFN-${\gamma}$, IL-2, IL-4, IL-6, IL-12, TNF-${\alpha}$ and IgG compared with the placebo. CONCLUSION: The results showed that supplementation with bacterial ${\beta}$-1,3-glucan significantly increased NK cell activity without causing any adverse effects. Additionally, the beneficial effect of ${\beta}$-1,3-glucan on NK cell activity was greater in participants experiencing severe stress.