• IMMUNE NETWORK
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• v.23 no.1
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• pp.7.1-7.27
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• 2023

The mammalian intestines harbor trillions of commensal microorganisms composed of thousands of species that are collectively called gut microbiota. Among the microbiota, bacteria are the predominant microorganism, with viruses, protozoa, and fungi (mycobiota) making up a relatively smaller population. The microbial communities play fundamental roles in the maturation and orchestration of the immune landscape in health and disease. Primarily, the gut microbiota modulates the immune system to maintain homeostasis and plays a crucial role in regulating the pathogenesis and pathophysiology of inflammatory, neuronal, and metabolic disorders. The microbiota modulates the host immune system through direct interactions with immune cells or indirect mechanisms such as producing short-chain acids and diverse metabolites. Numerous researchers have put extensive efforts into investigating the role of microbes in immune regulation, discovering novel immunomodulatory microbial species, identifying key effector molecules, and demonstrating how microbes and their key effector molecules mechanistically impact the host immune system. Consequently, recent studies suggest that several microbial species and their immunomodulatory molecules have therapeutic applicability in preclinical settings of multiple disorders. Nonetheless, it is still unclear why and how a handful of microorganisms and their key molecules affect the host immunity in diverse diseases. This review mainly discusses the role of microbes and their metabolites in T helper cell differentiation, immunomodulatory function, and their modes of action.

• Molecules and Cells
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• v.42 no.7
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• pp.503-511
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• 2019

As sessile organisms, plants have developed sophisticated system to defend themselves against microbial attack. Since plants do not have specialized immune cells, all plant cells appear to have the innate ability to recognize pathogens and turn on an appropriate defense response. The plant innate immune system has two major branches: PAMPs (pathogen associated molecular patterns)-triggered immunity (PTI) and effector-triggered immunity (ETI). The ability to discriminate between self and non-self is a fundamental feature of living organisms, and it is a prerequisite for the activation of plant defenses specific to microbial infection. Arabidopsis cells express receptors that detect extracellular molecules or structures of the microbes, which are called collectively PAMPs and activate PTI. However, nucleotidebinding site leucine-rich repeats (NB-LRR) proteins mediated ETI is induced by direct or indirect recognition of effector molecules encoded by avr genes. In Arabidopsis, plasmamembrane localized multifunctional protein RIN4 (RPM1-interacting protein 4) plays important role in both PTI and ETI. Previous studies have suggested that RIN4 functions as a negative regulator of PTI. In addition, many different bacterial effector proteins modify RIN4 to destabilize plant immunity and several NB-LRR proteins, including RPM1 (resistance to Pseudomonas syringae pv. maculicola 1), RPS2 (resistance to P. syringae 2) guard RIN4. This review summarizes the current studies that have described signaling mechanism of RIN4 function, modification of RIN4 by bacterial effectors and different interacting partner of RIN4 in defense related pathway. In addition, the emerging role of the RIN4 in plant physiology and intercellular signaling as it presents in exosomes will be discussed.

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1583-1590
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• 2021

Studies have demonstrated that PE_PGRS45 is constitutively expressed under various environmental conditions (such as nutrient depletion, hypoxia, and low pH) of the in vitro growth conditions examined, indicating that PE_PGRS45 protein is critical to the basic functions of Mycobacterium tuberculosis. However, there are few reports about the biochemical function and pathogenic mechanism of PE_PGRS45 protein. The fact that this M. tuberculosis gene is not easily expressed in E. coli may be mainly due to the high content of G+C and the use of unique codons. Fusion tags are indispensable tools used to improve the soluble expression of recombinant proteins and accelerate the characterization of protein structure and function. In the present study, His6, Trx, and His6-MBP were used as fusion tags, but only MBP-PE_PGRS45 was expressed solubly. The purification using His6-MBP tag-specific binding to the Ni column was easy to separate after the tag cleavage. We used the purified PE_PGRS45 to immunize New Zealand rabbits and obtained anti-PE_PGRS45 serum. We found that the titer of polyclonal antibodies against PE_PGR45 was higher than 1:256000. The result shows that purified PE_PGRS45 can induce New Zealand rabbits to produce high-titer antibodies. In conclusion, the recombinant protein PE_PGRS45 was successfully expressed in E. coli and specific antiserum was prepared, which will be followed by further evaluation of these specific antigens to develop highly sensitive and specific diagnostic tests for tuberculosis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.580-583
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• 2009

This paper introduces a gate drive IC for power modules with shoot-through immunity. A new approach uses a bootstrap diode as a high-side voltage bias and a level shift function at the same time. Therefore, the gate drive circuit becomes a simple and low-cost without conventional level shift functions such as HVIC(High-Voltage IC), optocoupler and transformer. The proposed gate drive IC is designed and fabricated using the Dongbu-Hitek's 0.35um BD350BA process. It has been tested and verified with IGBT modules.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.81-82
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• 2009

This paper introduces a gate drive IC for power modules with shoot-through immunity. A new approach uses a bootstrap diode as a high-side voltage bias and a level shift function at the same time. Therefore, the gate drive circuit becomes a simple and low-cost without conventional level shift functions such as HVIC(High-Voltage IC), optocoupler and transformer. The proposed gate drive IC is designed and fabricated using the Dongbu-Hitek's 0.35um BD350BA process. It has been tested and verified with IGBT modules.

• Journal of Life Science
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• v.18 no.6
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• pp.891-896
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• 2008

The function of mast cells as effector cells in allergy has been extensively studied. Mast cells activated through high affinity IgE-receptor ($Fc{\varepsilon}RI$) release diverse mediators, and lead to smooth muscle constriction, vasodilation, increase of vascular permeability, leukocyte recruitment and activation, mucus secretion, and tissue proliferation and remodeling. However, various other immunological and non-immunological signals can lead to the activation of mast cells. In resent years, mast cells have been identified to be involved in a complex range of immune functions. Mast cells can be important as key players in the regulation of innate as well as adapted immune responses, and may influence the development of allergy, autoimmune disorder and peripheral tolerance. This review summarizes the recent advances in the understanding of effector functions of mast cells in immune responses.

• Journal of Food Hygiene and Safety
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• v.2 no.4
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• pp.191-196
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• 1987

Erythrosine used as a colouring agent in drugs, cosmetics and foods in Korea, was examined for its effects on murine immune system and methemoglobin formation. As immunotoxicologic assay parameters, we adopted circulating leukocytes and immunoorgan weights for pathotoxicology, IgM plaque forming cells and arthus reaction for humoral immunity, delayed hypersensitivity reaction of cell mediated immunity and carbon clearacnce for macrophage function. Erythrosine's effects were observed as follows; 1. Ery throsine showed no significant effects on circulating leulocyte counts and relative immunoorgan weight. 2. Erythrosine diminished IgM plaque forming cells. 3. Erythrosine decreased arthus reaction, in the dose dependent manner. 4. Erythrosine had no significant effect on delayed hypersensitivity. 5. Phagocytic and corrected phagocytic index were not affected. 6. Methemoglobin content was similar in the test and control groups.

• YAKHAK HOEJI
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• v.46 no.1
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• pp.52-57
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• 2002

Effects of the butanl fraction of Astragali Radix (BFAR) on the cellular and nonspecific immune responses were investigated in ICR mice. Mice were divided into 4 groups and BFAR at doses of 5, 25 and 125 mg/kg u ere administered orally to mice daily for 3 weeks, and the normal animals were given vehicle. The results of this study are summarized as follows; the relative weight of thymus was greatly increased by BFAR treatment, compared with that in mormal mice. However, the body weight gain was not affected. Delayed-type hypersensitivity (DTH) reaction to sheep red blood cells (SRBC) for cellular immunity was significantly enhanced by BFAR treatment, compared with those in normal mice. In these mice, BFAR also dose-dependently increased activities of phagocyte and natural killer (NK) cells as well as the number of leukocyte resulted from nonspecific immunity Thus, these results demonstrate that BFAF treatment results in a significant increase in both cellular and nonspecific immune responses to antigen in concentrations that enhance humoral immune function.

• Molecules and Cells
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• v.20 no.2
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• pp.173-182
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• 2005

Heat shock protein gp96 is an endoplasmic reticulum chaperone, belonging to the HSP90 family. The function of gp96 as a molecular chaperone was discovered more than 10 years ago, but its importance has been overshadowed by the brilliance of its role in immune responses. It is now clear that gp96 is instrumental in the initiation of both the innate and adaptive immunity. Recently, the roles of gp96 in protein homeostasis, as well as in cell differentiation and development, are beginning to draw more attention due to rapid development in the structural study of HSP90 and some surprising new discoveries from genetic studies of gp96. In this review, we focus on the aspect of gp96 as an ER molecular chaperone in protein maturation, peptide binding and the regulation of its activity.

• IMMUNE NETWORK
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• v.22 no.6
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• pp.46.1-46.25
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• 2022

T-helper-17 (Th17) cells and related IL-17-producing (type17) lymphocytes are abundant at the epithelial barrier. In response to bacterial and fungal infection, the signature cytokines IL-17A/F and IL-22 mediate the antimicrobial immune response and contribute to wound healing of injured tissues. Despite their protective function, type17 lymphocytes are also responsible for various chronic inflammatory disorders, including inflammatory bowel disease (IBD) and colitis associated cancer (CAC). A deeper understanding of type17 regulatory mechanisms could ultimately lead to the discovery of therapeutic strategies for the treatment of chronic inflammatory disorders and the prevention of cancer. In this review, we discuss the current understanding of the development and function of type17 immune cells at the intestinal barrier, focusing on the impact of microbiota-immune interactions on intestinal barrier homeostasis and disease etiology.