• Journal of the Korean Ceramic Society
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• v.23 no.1
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• pp.44-50
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• 1986

Si-ZnO n-n heterojunction diodes were prespared by r.f diode sputtering of the sintered ZnO target on n-type Si single crystal wafers and their structures and electrical properties were studied. The films were grown orientedly with the c-axis of crystallites perpendicular to the substrate surface at low r.f. powder and grown to polycrystalline films with random orientation at high r. f. powder. The crystallite size increased with the increasing substrate temperture The oriented texture films only were used to prepare the photovoltaic diodes and these didoes showed the photovoltaic effect veing positive of the ZnO side for the photons in the wavelength range of 380-1450nm. The sign reversal of phootovoltage which is the property os isotype heterojunction was not observed because of the degeneration of the ZnO films. The diode showed the forward rectification when it was biased with the ZnO side positive. The current-voltage characteristics exhibited the thermal-current type relationship J∝exp(qV/nkT) with n=1.23 at the low forward bias voltage and the tunnelling-current type relationship J∝exp($\alpha$V) where $\alpha$ was constant independent of temperature at the high forward bias voltage. The crystallite size of ZnO films were influenced largely on the photovoltaic properties of diodes ; The diodes with the films of the larger crystallites showed the poor photovoltaic properties. This reason may be cosidered that the ZnO films with the large crystallites could not grow to the electrically continuous films because the thickness of films was so thin in this experiment.

• Proceedings of the Microbiological Society of Korea Conference
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• 1991.04a
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• pp.82-96
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• 1991

To understand the mechanism of illegitimate recombination in mammalian cells, we have examined the recombination role of DNA topoisomerase II (Topo II ). We found that purified calf thymus Topo II mediates recombination between two phage $\lambda$ DNA molecules in an in vitro system. The enzyme mainly produced a linear monomer recombinant DNA that can be packaged in vitro. Novobiocin and anti-calf thymus Topo II antibody inhibit this ATP-dependent recombination. The recombinant molecules contain duplications or deletion, and most crossovers take place between nonhomologous sequences of $\lambda$ DNA, as judged by the sequences of recombination junctions. In order to study the effects of Topo II on illegitimate recombination in mammalian cells, we have developed a new shuttle vector, pNKl, which contains three bacterial genes, amp(APR), galK and neo($Km^R$). Using this system, we have shown that a Topo II inhibitor, VM26, stimulated deletion formation in pNK1 DNA in monkey COS1 cells. Both in vitro and in vivo results suggest that Topo II participates in illegitimate recombination in mammalian cells.

• IMMUNE NETWORK
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• v.6 no.2
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• pp.67-75
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• 2006

Background: Cytotoxic function of killer cells is inhibited by specific recognition of class I MHC molecules on target cells by inhibitory killer Ig-like receptors (KIR) expressed on NK cells and some cytotoxic T cells. The inhibitory effect of KIR is accomplished by recruitment of SH2-containing protein tyrosine phosphatase (SHP) to the phosphotyrosine residues in the cytoplasmic tail. Methods: By in vitro coprecipitation experiments and transfection analysis, we investigated the association of KIR with an adaptor protein Shc in Jurkat T cells. Results: The cytoplasmic tail of KIR appeared to associate with an adaptor protein Shc in Jurkat T celilysates. Similar in vitro experiments showed that phosphorylated KIR cytoplasmic tail bound SHP-1 and Shc in Jurkat T cell lysates. The association of KIR with Shc was further confirmed by transfection analysis in 293T cells. Interestingly, however, Shc appeared to be replaced by SHP-2 upon engagement of KIR in 293T cells. Conclusion: Our data indicate that KIR associate with an adaptor protein Shc in Jurkat T cells, and suggest that KIR might have an additional role which is mediated by this adaptor protein.

• Food preservation and processing industry
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• v.6 no.2
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• pp.11-13
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• 2007

This study relates to low and medium molecular weight isoflavone-${\beta}$-D-glucan produced by submerged liquid culture of Agaricus blazei, a method of producing the isoflavone-B-D-glucan using autolysis enzyme of Agaricus blazei mycelia, and use of the isoflavone-B-D-glucan for anti-cancer and immunoenhancing effect. In acordance with one aspect of the present study, it deals with a method of producing isoflavone-${\beta}$-D-glucan, which comprises the followings; 1) culturing and separating mushroom mycelia, 2) producing low-medium molecular weight isoflavone-${\beta}$-D-glucan from high molecular weight one. The cytotoxicity on human cnacer cell line (Caco-2, MCF-7), the expression of Cyclin D, Bcl-2, Bax protein, p21 protein, p53 protein in MCF-7 cells assessed by SDS-PAGE and immunoblotting, and other immuno related factor such as TNF-a and IL-1B activities were examined. Structural identification of isoflavone-${\beta}$-D-glucan which shoed cytotoxicity against cancer cell and immunoenhancing effects was carried by separation with DEAE-cellulose column chromatography, TLC, HPLC, IR, NMR, Clinical test for the cancer patients (n=119) for 6 month was carried out, and immunoenhancing factors(NK cell number, ratio of T4/T8) were checked. We concluded the identified isoflavone-${\beta}$-D-glucan has immuno enhancing effects and could be useful for cancer chemoprevention.

• BMB Reports
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• v.55 no.1
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• pp.39-47
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• 2022

Adoptive cell transfer (ACT), a form of cell-based immunotherapy that eliminates cancer by restoring and strengthening the body's immune system, has revolutionized cancer treatment. ACT entails intravenous transfer of either tumor-resident or peripheral blood-modified immune cells into cancer patients to mediate anti-tumor response. Although these immune cells control and eradicate cancer via enhanced cytotoxicity against specific tumor antigens, several side effects have been frequently reported in clinical trials. Recently, exosomes, potential cell-free therapeutics, have emerged as an alternative to cell-based immunotherapies, due to their higher stability under same storage condition, lower risk of GvHD and CRS, and higher resistance to immunosuppressive tumor microenvironment. Exosomes, which are nano-sized lipid vesicles, are secreted by living cells, including immune cells. Exosomes contain proteins, lipids, and nucleic acids, and the functional role of each exosome is determined by the specific cargo derived from parental cells. Exosomes derived from cytotoxic effectors including T cells and NK cells exert anti-tumor effects via proteins such as granzyme B and FasL. In this mini-review, we describe the current understanding of the ACT and immune cell-derived exosomes and discuss the limitations of ACT and the opportunities for immune cell-derived exosomes as immune therapies.

• IMMUNE NETWORK
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• v.24 no.1
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• pp.11.1-11.18
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• 2024

IL-15 belongs to the common gamma chain cytokine family and has pleiotropic immunological functions. IL-15 is a homeostatic cytokine essential for the development and maintenance of NK cells and memory CD8⁺ T cells. In addition, IL-15 plays a critical role in the activation, effector functions, tissue residency, and senescence of CD8⁺ T cells. IL-15 also activates virtual memory T cells, mucosal-associated invariant T cells and γδ T cells. Recently, IL-15 has been highlighted as a major trigger of TCR-independent activation of T cells. This mechanism is involved in T cell-mediated immunopathogenesis in diverse diseases, including viral infections and chronic inflammatory diseases. Deeper understanding of IL-15-mediated T-cell responses and their underlying mechanisms could optimize therapeutic strategies to ameliorate host injury by T cell-mediated immunopathogenesis. This review highlights recent advancements in comprehending the role of IL-15 in relation to T cell responses and immunopathogenesis under various host conditions.

• IMMUNE NETWORK
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• v.22 no.1
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• pp.5.1-5.22
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• 2022

The approval of immunotherapies such as checkpoint inhibitors (CPIs), adoptive cell therapies and cancer vaccines has revolutionized the way cancer treatment is approached. While immunotherapies have improved clinical outcome in a variety of tumor types, some cancers have proven harder to combat using single agents, underscoring the need for multi-targeted immunotherapy approaches. Efficacy of CPIs and cancer vaccines requires patients to have a competent immune system with adequate cell numbers while the efficacy of adoptive cellular therapy is limited by the expansion and persistence of cells after infusion. A promising strategy to overcome these challenges is combination treatment with common gamma-chain cytokines. Gamma-chain cytokines play a critical role in the survival, proliferation, differentiation and function of multiple immune cell types, including CD8 T-cells and NK cells, which are at the center of the anti-tumor response. While the short halflife of recombinant cytokines initially limited their application in the clinic, advancements in protein engineering have led to the development of several next-generation drug candidates with dramatically increased half-life and bioactivity. When combining these cytokines with other immunotherapies, strong evidence of synergy has been observed in preclinical and clinical cancer settings. This promising data has led to the initiation of 70 ongoing clinical trials including IL-2, IL-7, IL-15 and IL-21. This review summarizes the recent advancements of common gamma-chain cytokines and their potential as a cancer immunotherapy.

• IMMUNE NETWORK
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• v.20 no.1
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• pp.6.1-6.20
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• 2020

IL-17 is produced by RAR-related orphan receptor gamma t (RORγt)-expressing cells including Th17 cells, subsets of γδT cells and innate lymphoid cells (ILCs). The biological significance of IL-17-producing cells is well-studied in contexts of inflammation, autoimmunity and host defense against infection. While most of available studies in tumor immunity mainly focused on the role of T-bet-expressing cells, including cytotoxic CD8⁺ T cells and NK cells, and their exhaustion status, the role of IL-17-producing cells remains poorly understood. While IL-17-producing T-cells were shown to be anti-tumorigenic in adoptive T-cell therapy settings, mice deficient in type 17 genes suggest a protumorigenic potential of IL-17-producing cells. This review discusses the features of IL-17-producing cells, of both lymphocytic and myeloid origins, as well as their suggested pro- and/or anti-tumorigenic functions in an organ-dependent context. Potential therapeutic approaches targeting these cells in the tumor microenvironment will also be discussed.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2325-2331
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• 2013

Objective: To detect effects of plumbagin on proliferation and apoptosis in non-small cell lung cancer cell lines, and investigate the underlying mechanisms. Materials and Methods: Human non-small cell lung cancer cell lines A549, H292 and H460 were treated with various concentrations of plumbagin. Cell proliferation rates was determined using both cell counting kit-8 (CCK-8) and clonogenic assays. Apoptosis was detected by annexin V/propidium iodide double-labeled flow cytometry and TUNEL assay. The levels of reactive oxygen species (ROS) were detected by flow cytometry. Activity of NF-${\kappa}B$ was examined by electrophoretic mobility shift assay (EMSA) and luciferase reporter assay. Western blotting was used to assess the expression of both NF-${\kappa}B$ regulated apoptotic-related gene and activation of p65 and $I{\kappa}B{\kappa}$. Results: Plumbagin dose-dependently inhibited proliferation of the lung cancer cells. The IC50 values of plumbagin in A549, H292, and H460 cells were 10.3 ${\mu}mol/L$, 7.3 ${\mu}mol/L$, and 6.1 ${\mu}mol/L$ for 12 hours, respectively. The compound concentration-dependently induced apoptosis of the three cell lines. Treatment with plumbagin increased the intracellular level of ROS, and inhibited the activation of NK-${\kappa}B$. In addition to inhibition of NF-${\kappa}B$/p65 nuclear translocation, the compound also suppressed the degradation of $I{\kappa}B{\kappa}$. ROS scavenger NAC highly reversed the effect of plumbagin on apoptosis and inactivation of NK-${\kappa}B$ in H460 cell line. Treatment with plumbagin also increased the activity of caspase-9 and caspase-3, downregulated the expression of Bcl-2, upregulated the expression of Bax, Bak, and CytC. Conclusions: Plumbagin inhibits cell growth and induces apoptosis in human lung cancer cells through an NF-${\kappa}B$-regulated mitochondrial-mediated pathway, involving activation of ROS.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.380-385
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• 2009

The purpose of this study was to investigate the immunomodulatory effect of Ulva pertusa kjellman extract after undergoing a low temperature and high-pressure extraction process. First, the extracts obtained under the extraction conditions of 150 MPa and $80^{\circ}C$showed a relatively high antioxidant activity, with 90% super oxide radical activity compared to the extracts from conventional extraction process with water at $100^{\circ}C$. This extract also improved the growth of both human immune B and T cells up to $14.5{\times}10^4$ cells/mL and $14.2{\times}10^4$ cells/mL compared to $9.1{\times}10^4$ cells/mL in adding the extracts from conventional processes. It was found that the extracts obtained at 100 MPa and $60^{\circ}C$ showed better activities in NK cell growth and NO production from macrophage as $11.8{\times}10^2$ cells/mL and 30.0 ${\mu}M$. Overall, the extracts from high pressure and low temperature extraction process had relatively higher immune activation activity, possibly because the low temperature and high pressure extraction process may have higher yields of active compounds and have less damage to useful ingredients from relatively weak marine natural resources, such as Ulva pertusa kjellmann than that from the conventional extraction system.