• YAKHAK HOEJI
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• v.50 no.1
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• pp.33-39
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• 2006

We have previously reported the minimum criteria that can be applied to evaluate efficacy and safety of a DNA vaccine with use of Streptococcus pneumoniae DNA vaccine (SPDNA). The SPDNA was formulated by inserting the DNA sequences that are codons specific for the carbohydrate epitope in the capsule of S. penumoniae by phage display peptide library. Administration of the SPDNA into mice induced both humoral and cell-mediated immunities. The induction was protective even in the absence of CD4+ T lymphocyte in mice. Profiles of cytokine and isotyping of antibody displayed tendency of the Th1. In continuation of these studies, we examined if the efficacy of the SPNDA was provoked by the peptide recognized by codons specific for the capsule. Results showed that the peptide vaccine formulae (SPP) induced protective antibody in mice as did the SPDNA. Involvement of the cell-mediated immunity was also determined. Possible side effects of autoimmune diseases such as myositis and C3a production and tumor-formation were undetectable in mice given 7 times of SPDNA vaccination during entire of 92 days. Even after the frequent immunization, immunogenicity of the SPDNA was observed as determined for antibody production, suggesting that there was no immunotolerance provoked. All together, these examining factors would be applied to measurement of a DNA vaccine safety regarding the immunopathological aspect.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.4
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• pp.227-232
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• 2003

A self-assembled monolayer of protein G was fabricated to develop an immunosensor based on surface plasmon resonance (SPR), thereby improving the performance of the antibodybased biosensor through immobilizing the antibody molecules (lgG). As such, 11-mercaptoundecanoic acid (11-MUA) was adsorbed on a gold (Au) support, while the non-reactive hydrophilic surface was changed through substituting the carboxylic acid group (-COOH) in the 11-MUA molecule using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrocholide (EDAC). The formation of the self-assembled protein G layer on the Au substrate and binding of the antibody and antigen were investigated using SPR spectroscopy, while the surface topographies of the fabricated thin films were analyzed using atomic force microscopy (AFM). A fabricated monoclonal antibody (Mab) layer was applied for detecting E. coli O157:H7. As a result, a linear relationship was achieved between the pathogen concentration and the SPR angle shift, plus the detection limit was enhanced up to 10$^2$ CFU/mL.

• Parasites, Hosts and Diseases
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• v.41 no.2
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• pp.89-96
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• 2003

Among the panel of monoclonal antibodies (mAb) against Toxoplasma gondii, mAb of Tg621 (Tg621) clone blotted 38 kDa protein which localized in the cytoplasm of tachyzoites by immunofluorescence microscopy The protein was not released into the parasitophorous vacuole during or after invasion. The cDNA fragment encoding the protein was obtained by screening a T. gondii cDNA expression library with Tg621. The full length cDNA sequence was completed with 5’-RACE as 1,592 bp, which contained open reading frame of 942 bp. The deduced amino acid sequence of Tg621 consisted of a polypeptide of 313 amino acids, with significant homology to ribosomal P proteins (RPP) of other organisms especially high to those of apicomplexan species. The expressed and purified TgRPP was assayed in western blot with the sera of toxoplasmosis patients and normal sera, which resulted in the 74.0% of positive reactions in toxoplasmosis patients whereas 8.3% in normal group. Therefore, the antibody formation against TgRPP in toxoplasmosis patients was regarded as specific for T. gondii infection and suggested a potential autoantibody.

• Journal of Life Science
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• v.9 no.3
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• pp.293-299
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• 1999

Accumulation of toxic waste byproducts in hybridoma culture can limit cell growth and monoclonal antibody (MAb) productivity, and one of the major toxic metabolites is lactate produced via glycolytic pathway of glucose metabolism. The factors affecting the glucose to lactate conversion rate were investigated. The conditions of high initial glucose concentration and high growth rate stimulated glucose to lactate conversion rate. The glucose-controlled fed-batch culture was investigated, and 19% reduction in lactate formation and 41% enhancement of MAb titer could be achieved by fed-batch culture.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1198-1203
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• 2007

Conidial adhesion and appressorium formation of Magnaporthe oryzae on the rice surface are important early events in the infection process. As an initiative step to understand the mechanisms underlying these cellular processes at a biochemical level, the effect of a human fibronectin antibody (HFA) and RGD peptides on conidial adhesion and appressorium formation was evaluated. HFA inhibited conidial adhesion and appressorium formation in a dosage-dependent manner. RGD peptides also inhibited these cellular events. Conidial adhesion and appressorium formation inhibited by RGD peptides were restored by chemicals involved in the cyclic AMP-dependent signaling pathway. These results suggest that extracellular matrix proteins might be involved in conidial adhesion and appressorium formation through integrin-like receptor mediation and modulation of cAMP-dependent signaling in the cells.

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.104-109
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• 2007

In this paper, we have fabricated on extended-gate field effect transistor (EGFET)-type protein sensor for the application to a CRP detection. We used the self-assembled monolayer (SAM) to adhere or entrap biomolecules, namely CRP antibodies. The experimental result shows that the proposed SAM is well immobilized on the gold gate surface. So the drain current was varied by antigen-antibody interactions on the gate surface because of the CRP charge. Experimental results related to the formation of SAM, antibody, antigen were obtained by measuring the electrical characteristics of the EGFET device.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.137-141
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• 2008

Biochip, which implements bioanalytical process on a tiny surface, is one of candidates for medical diagnosis, drug screening, and molecular sensing. In general, a type of biochip based on microfluidics is composed of microcomponents including microchannel, pump, and valve, which require complicated processes. In this study, gray-scale photolithography(GSPL) was applied to fabricate a biochip with multiple layers. A mould for casting PDMS(polydimethylsiloxane) channel, was fabricated using GSPL. A gray-photomask was prepared by printing gray patterns on a high-quality glossy paper followed by photoreducing by 10:1 onto the photo-film. The formation of multiple layers was studied according to the change of gray level of pattern and the developing time. A biochip composed of a weir(multiple layer structure) and a reaction chamber in a single microchannel was fabricated in a glass plate. Finally, we investigated the application of biochip to antigen-antibody reaction by packing the microbead coated with antibody.

• IMMUNE NETWORK
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• v.12 no.6
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• pp.230-239
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• 2012

Activation-induced cytidine deaminase (AID) is an enzyme that is predominantly expressed in germinal center B cells and plays a pivotal role in immunoglobulin class switch recombination and somatic hypermutation for antibody (Ab) maturation. These two genetic processes endow Abs with protective functions against a multitude of antigens (pathogens) during humoral immune responses. In B cells, AID expression is regulated at the level of either transcriptional activation on AID gene loci or post-transcriptional suppression of AID mRNA. Furthermore, AID stabilization and targeting are determined by post-translational modifications and interactions with other cellular/nuclear factors. On the other hand, aberrant expression of AID causes B cell leukemias and lymphomas, including Burkitt's lymphoma caused by c-myc/IgH translocation. AID is also ectopically expressed in T cells and non-immune cells, and triggers point mutations in relevant DNA loci, resulting in tumorigenesis. Here, I review the recent literatures on the function of AID, regulation of AID expression, stability and targeting in B cells, and AID-related tumor formation.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.135.2-135.2
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• 2003

Plasma membrane blebs are observed in many types of apoptotic cells, but their processes of formation remain to be clarified. In the present study, we investigated whether there is a relationship between change of intracellular phosphotyrosine levels and biochemical apoptotic events in Jurkat T cells undergoing apoptosis by agonistic anti-Fas antibody. When Jurkat cells were treated with Fas-antibody in the presence or absence of pretreatment with sodium orthovanadate ($Na_3${VO}_4$), a phosphotyrosine phosphatase (PTPase) inhibitor, membrane blebs disappeared in orthovanadate-treated cells. (omitted)

• BMB Reports
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• v.52 no.6
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• pp.397-402
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• 2019

Middle East respiratory syndrome coronavirus (MERS-CoV) uses the spike (S) glycoprotein to recognize and enter target cells. In this study, we selected two epitope peptide sequences within the receptor binding domain (RBD) of the MERS-CoV S protein. We used a complex consisting of the epitope peptide of the MERS-CoV S protein and CpG-DNA encapsulated in liposome complex to immunize mice, and produced the monoclonal antibodies 506-2G10G5 and 492-1G10E4E2. The western blotting data showed that both monoclonal antibodies detected the S protein and immunoprecipitated the native form of the S protein. Indirect immunofluorescence and confocal analysis suggested strong reactivity of the antibodies towards the S protein of MERS-CoV virus infected Vero cells. Furthermore, the 506-2G10G5 monoclonal antibody significantly reduced plaque formation in MERS-CoV infected Vero cells compared to normal mouse IgG and 492-1G10E4E2. Thus, we successfully produced a monoclonal antibody directed against the RBD domain of the S protein which could be used in the development of diagnostics and therapeutic applications in the future.