• BMB Reports
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• 제44권4호
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• pp.217-231
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• 2011

T cell exhaustion develops under conditions of antigen-persistence caused by infection with various chronic pathogens, such as human immunodeficiency virus (HIV) and myco-bacterium tuberculosis (TB), or by the development of cancer. T cell exhaustion is characterized by stepwise and progressive loss of T cell function, which is probably the main reason for the failed immunological control of chronic pathogens and cancers. Recent observations have detailed some of the intrinsic and extrinsic factors that influence the severity of T cell exhaustion. Duration and magnitude of antigenic activation of T cells might be associated with up-regulation of inhibitory receptors, which is a major intrinsic factor of T cell exhaustion. Extrinsic factors might include the production of suppressive cytokines, T cell priming by either non-professional antigenpresenting cells (APCs) or tolerogenic dendritic cells (DCs), and alteration of regulatory T (Treg) cells. Further investigation of the cellular and molecular processes behind the development of T cell exhaustion can reveal therapeutic targets and strategies for the treatment of chronic infections and cancers. Here, we report the properties and the mechanisms of T cell exhaustion in a chronic environment.

• 한국가금학회지
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• 제26권2호
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• pp.131-144
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• 1999

Coccidiosis, an intestinal infection caused by intracellular protozoan parasites belonging to several different species of Eimeria seriously impairs the growth and feed utilization of livestock and poultry. Due to complex life cycle of organism and intricate host immune responses to Elmeria, coccidia vaccine development has been difficult. Understanding of basic imunobiology of pertinent host-parasite interactions is necessary for the development of novel control strategy. Although chickens infected with Eimeria spp. produce parasite-specific antibodies in both the circulation and mucosal secretions, antibody mediated responses play a minor role in protection gainst coccidiosis. Rather, increasing evidence show that cell-mediated immunity plays a major role in resistance to coccidiosis. T-lymphocytes appear to respond to coccidiosis both through cytokine production and a direct cytotoxic attack on infected cells. The exact mechanisms by which T-cells eliminate the parasites, however, remain to be investigated. Since it is crucial to understand the intestinal immune system in order to develop an immunological control strategy against any intestinal immune system in order to develop an immunological control strategy against any intestinal diseases, this presentation will summarize our current understanding of the avian intestinal immune system and mucosal immune responses to Eimeria, to provide a conceptual overview of the complex molecular and cellular events involved in intestinal immune responses to enteric pathogens.

• 대한의생명과학회지
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• 제8권3호
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• pp.107-113
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• 2002

Enterohemorrhagic Escherichia coli (EHEC) strains of serotype O157:H7 have been shown to colonize the intestinal epithelial cell by the attaching and effacing (AE) mechanism. The AE lesion is mediated by an intimin, of which production and expression are controlled by a 3-Kb eaeA gene located EHEC chromosomal DNA. If the eaeA gene is mutated, EHEC O157:H7 strains lose capacity of adhesion to intestinal epithelial cells. In this study, a 891 bp of the 3'-end region of a gamma intimin was amplified by polymerase chain reaction (PCR). The PCR product was inserted into pSTBlue-1 cloning vector and transformed into DE3 (BL21) competent cell. After plasmid mini-preparation and restriction enzyme digestion of eaeA/891-pSTBlue-1 vector, target eaeA gene was re-inserted into pET-28a expression vector and was transformed. Then the expression of recombinant eaeA/891 (891 bp) gene was induced by isopropyl-$\beta$-D-thiogalactopyranoside (IPTG). The expression of the 40-KDa recombinant protein was identified in SDS-PAGE and confirmed by immunoblotting using the His.Tag$^{\circledR}$ and T$_{7}$.Tag$^{\circledR}$ monoclonal antibody. This recombinant protein expressed by eaeA gene could be applied in further studies on the mechanisms of E. coli O157:H7 infection and the development of recombinant vaccine.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1264-1269
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• 2011

Interleukin-2 (IL-2) is a vital cytokine secreted by activated T lymphocytes, and plays an important role in the regulation of cellular functions and immunity of animals. In this study, the recombinant duck IL-2 (rduIL-2) was secretory expressed in Pichia pastoris (P. pastoris). The recombinant P. pastoris strain was cultured in shake flasks and then scaled up in a 5.0-l bioreactor. The result showed that the maximal fresh-cell-weight of 594.1 g/l and the maximal $OD_{600}$ of 408 were achieved in the bioreactor. The rduIL-2 was purified by two steps of purification procedures, and approximately 311 mg of rduIL-2/L fermentation supernatant was obtained. SDS-PAGE showed that the purified rduIL-2 constituted a homogeneous band of ~16 kDa or ~14 kDa corresponding to the glycosylated or non-glycosylated duIL-2 protein in size, respectively. The bioactivity of rduIL-2 was determined by lymphocyte proliferation assay. The result indicated that the rduIL-2 greatly promoted the proliferation of ConA-stimulated lymphocytes in vitro. The P. pastoris expression system described here could provide promising, inexpensive, and large-scale production of the rduIL-2, which lays the foundation for development of novel immunoadjuvants to enhance both the immunity of ducks against various infectious pathogens and vaccine efficacy.

• 대한수의학회지
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• 제38권2호
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• pp.336-344
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• 1998

Eight monoclonal antibodies(MAbs) against the transmissible gastroenteritis virus (TGEV) were produced and characterized. Four of the MAbs were produced against a reference TGEV, Purdue strain(P115) and the others were produced against the Korean vaccine virus, Pyungtaek strain. Only one MAb(5C8) produced against P115 had neutralizing activity and was found to be E2 protein-specific. The other seven MAbs(4E2, 4G8, 5H6, 1F8, 2C6, 5H5, and 3A6) had specificity of nucleocapsid protein and no neutralizing activity. All MAbs reacted with different strains of TGEV, but none of the MAbs was reactive with porcine enteropathogenic viruses such as rotavirus, epidemic diarrhea virus and enterovirus by fluorescence antibody(FA) test.

• 한국수산과학회지
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• 제52권6호
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• pp.644-649
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• 2019

Killed vaccines, developed by inactivation with formalin, have been investigated for many fish viruses. In this study, the inactivation of viral hemorrhagic septicemia virus (VHSV) by formalin was investigated based on the infectivity titer. When viral cell culture supernatants were used, the infectivity titer decreased 1,000-fold at 1 d after treatment with 0.1% (v/v) formalin, but was below the detection limit at 7 and 14 d. Moreover, neither the N nor G gene were detectable by RT-PCR immediately after formalin treatment. In western blot analysis, N protein was not detected by rabbit antiserum against VHSV KR-9225 from 2 d after formalin treatment. On the other hand, when we used a virus that was purified and concentrated ~100 times, the infectivity titer was maintained at 10^6.05 TCID₅₀/mL, even at 14 d after formalin treatment, and no change in the viral structural proteins was observed. This study provides important data on the production and use of formalin-inactivated vaccines.

• 한국동물위생학회지
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• 제40권3호
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• pp.187-192
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• 2017

In this report, fifteen monoclonal antibodies (MAbs) against an avian influenza virus (H9N2 subtype) were newly produced and characterized. These MAbs proved to react to the epitopes of nucleocapsid protein (NP), hemagglutinin (HA), neuraminidase (NA) and non-structural protein 1 (NS1) of Korean H9N2 strain, respectively. Two HA-specific MAbs showed the ability to inhibit the hemagglutination activity of H9N2 subtype avian influenza virus when tested by hemagglutination inhibition (HI) assay. All MAbs did not cross-react with other avian-origin viruses (Newcastle disease virus, infectious bursal disease virus, infectious bronchitis virus and avian rotavirus) by immunofluorescence test or enzyme-linked immunosorbent assay. The MAbs produced in this study could be useful as the materials for diagnostics and therapeutics against Korean-lineage H9N2 virus infections.

• 한국동물위생학회지
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• 제25권3호
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• pp.275-283
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• 2002

Forty strains of Staphylococcus aureus were isolated from mastitic milk. As a result of antimicrobial susceptibility test, the strains of S aureus revealed 47.5% were resistant to ampicillin and penicillin, and 7.5% to gentamicin. But 45% of isolates were sensitive to antimicrobial agents tested. In case of enterotoxin production, 56.3% of 16 strains produced enterotoxin D. Two strain of enterotoxin D producers produced both enterotoxin B and D. According to isolation date, 15 representative strains were selected. As a results of pulsed field gel eletrophoresis analysis of the 15 representative strains, 14 strains were identical. Therefore we consider the identical strains of S aureus have caused continuously bovine mastitis in this dairy farm. If autogenous vaccine can be made by the strains, it will work well for the prevention of bovine mastitis caused by S aureus.

• Fisheries and Aquatic Sciences
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• 제22권7호
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• pp.14.1-14.8
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• 2019

Olive flounder (Paralichthys olivaceus) is the major species developed for aquaculture in South Korea. Over the long history of olive flounder aquaculture, complex and diverse diseases have been a major problem, negatively impacting industrial production. Vibriosis is a prolific disease which continuously damages olive flounder aquaculture. A bacterial disease survey was performed from January to June 2017 on 20 olive flounder farms on Jeju Island. A total of 1710 fish were sampled, and bacteria from the external and internal organs of 560 fish were collected. Bacterial strains were identified using 16 s rRNA sequencing. Twenty-seven species and 184 strains of Vibrio were isolated during this survey, and phylogenetic analysis was performed. Bacterial isolates were investigated for the distribution of pathogenic and non-pathogenic species, as well as bacterial presence in tested organs was characterized. V. gigantis and V. scophthalmi were the dominant non-pathogenic and pathogenic strains isolated during this survey, respectively. This study provides data on specific Vibrio spp. isolated from cultured olive flounder in an effort to provide direction for future research and inform aquaculture management practices.

• BMB Reports
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• 제56권7호
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• pp.392-397
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• 2023

In this study, recombinant Fc-fused Prostate acid phosphatase (PAP) proteins were produced in transgenic plants. PAP was fused to immunoglobulin (Ig) A and M Fc domain (PAP-IgA Fc and PAP-IgM Fc), which were tagged to the ER retention sequence KDEL to generate PAP-IgA FcK and PAP-IgM FcK. Agrobacterium-mediated transformation was performed to produce transgenic tobacco plants expressing four recombinant proteins. Genomic PCR and RT-PCR analyses confirmed the transgene insertion and mRNA transcription of PAP-IgA Fc, PAP-IgM Fc, PAP-IgA FcK, and PAP-IgM FcK in tobacco plant leaves. Western blot confirmed the expression of PAP-IgA Fc, PAP-IgM Fc, PAP-IgA FcK, and PAP-IgM FcK proteins. SEC-HPLC and Bio-TEM analyses were performed to confirm the size and shape of the plant-derived recombinant PAP-Fc fusion proteins. In mice experiments, the plant-derived IgA and IgM Fc fused proteins induced production of total IgGs including IgG1 against PAP. This result suggests that IgA and IgM Fc fusion can be applied to produce recombinant PAP proteins as a prostate cancer vaccine in plant expression system.