• Korean Journal of Microbiology
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• v.54 no.4
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• pp.330-342
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• 2018

The Streptavidin and Biotin system has been studied most extensively as the high affinity non-covalent binding of Biotin to STR ($K_D=10^{-14}M$) and four Biotin binding sites in tetrameric Streptavidin makes this system useful for the production of multivalent antibody. For the application of this system, we cloned Streptavidin amplified from Streptomyces avidinii chromosome by PCR and fused to gene of hAY4 single-chain Fv antibody specific to death receptor 4 (DR4) which is a receptor for tumor necrosis factor ${\alpha}$ related apoptosis induced ligand. The hAY4 single-chain Fv antibody fused to Streptavidin expressed in Escherichia coli showed 43 kDa monomer in heated SDS-PAGE. However, this fusion protein shown in both non-heated SDS-PAGE and Size-exclusion chromatography exhibited 172 kDa as a tetramer suggesting that natural tetramerization of Streptavidin by non-covalent association induced hAY4 single-chain Fv tetramerization. This fusion protein retained a Biotin binding activity similar to natural Streptavidin as shown in Ouchterlony assay and ELISA. Death receptor 4 antigen binding activity of purified hAY4 single-chain Fv fused to Streptavidin was also confirmed by ELISA and Westernblot. In addition, surface plasmon resonance analysis showed 60-fold higher antigen binding affinity of the hAY4-STR than monomeric hAY4 ScFv due to tetramerization. In summary, hAY4 single-chain Fv fused to Streptavidin fusion protein was successfully expressed and purified as a soluble tetramer in E. coli and showed both Biotin and DR4 antigen binding activity suggesting possible production of bifunctional and tetrameric ScFv antibody.

• Journal of Life Science
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• v.12 no.4
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• pp.460-463
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• 2002

Twelve clones of monoclonal antibodies (mAbs) against thyroglobulin were produced and characterized. Among them, three mAbs (TN-1, TN-2 and TN-3) showed high binding affinity to thyroglobulin. from ELISA inhibition assay, TN-2 showed considerable reactivity with soluble thyroglobulin. TN-2 also reacted with phosphatidylserine which has a negative charge in aqueous condition. These results suggest that TN-2 has characteristics of autoantibody concerned with thyroiditis.

• Journal of Microbiology
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• v.37 no.3
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• pp.180-184
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• 1999

hybridoma cells producing IgM anti-pneuococcal 6B polysaccharide antibodies were induced to switch to IgG-producing cells in vitro by treating with acridine orange. Treating 0.5 $\mu\textrm{g}$/ml of acridine orange for 24 hours generated maximal number of variant cells. The maximal isotype switch frequency was 3${\times}$10-5, which is about 30-fold higher than the frequency of spontaneous switching. Resulting IgG-producing variants were enriched by sib selection and ELISA spot assay. Two IgG3-producing variant cells were finally cloned by limiting dilution. The variant cells produced similar amounts of antibodies as their parental cells did. The two switched antibodies had similar reactivity to pneumococcal 6B polysaccharide. When compared to their parental IgM antibodies, the switched IgG3 than that of IgM antibody. The antibodies will be useful as essential tools for comparative study of the role of heavy chain isotypes in protection against Streptococcus pneumoniae.

• Korean Journal of Animal Reproduction
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• v.14 no.3
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• pp.165-173
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• 1990

A simple and sensitive microplate enzyme immunoassay(ELISA) was developed for progesterone, based on progesterone monoclonal antibody as anti-progesterone, horseradish peroxise(HRP) as enzyme-label and tetramethylbenzidine(TMB) as substrate. The assay has a sensitivity of 5pg-120pg/well and intra- and inter assay coefficients of variation for progesterone standard curve(0.1ng-3.2ng/ml) were ranged 4.4-10.6% and 5.-12.6%, respectively. They assay is performed in less than two hours and provide reliable values to differentiate among samples from day 0(A.I.), day 14 and day 19. The discriminatory levels for early pregnancy diagnosis are [>10ng(day 19) & decreasing rate <1.5 : pregnancy] and [ 7ng & decreasing rate 1.5 : non-pregnancy]. The accuracy of the pregnancy diagnosis for cows classified as positive(pregnancy) and negative(non-pregnancy) were 96% and 100%, respectively.

• YAKHAK HOEJI
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• v.36 no.2
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• pp.188-190
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• 1992

Two clones of monconal antibodies(Co-1 and Co-2) against BSA-benzoylecgonine(BSABE) were produced. Both monoclonal antibodies showed high binding affinity to BSA-BE. Observing from ELISA inhibition assay, Co-1 reacted only weakly with soluble benzoylecgonine, while Co-2 showed considerable reactivity with soluble benzoylecgonine.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.385-391
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• 2006

In Korea, different kinds of genetically modified (GM) crops are under development, including GM-rice expressing insecticidal crystal (Cry) proteins of Bacillus thuringiensis (Bt) modified to change a single amino acid. In this study, amino acid (aa) sequences of modified Cry proteins were compared to that of known allergens, and Cry proteins expressed in GM-rice were identified by using Cry protein specific polyclonal antibody. The antigen-antibody reactions were compared between GM and commercial rice to assess the allergic risk of Cry proteins. This analysis showed no known allergen to have more than 35% aa sequence homology with modified Cry proteins in Bt rice over an 80 aa window or to have more than 8 consecutive identical aa. Sera from allergic patients showed some IgE reactivity via immunoblotting and enzyme-linked immunosorbent assay (ELISA), although no differences were seen between GM and commercial rice. Based on these results we conclude that GM rice with modified Cry proteins has no differences in its protein composition or allergenicity relative to commercial rice.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.173-178
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• 2001

A monoclonal antibody (mAb) to the glucoprotein D (gD) of Herpes simplex virus type 2 (HSV-2) was successfully generated by hybridoma technology and characterized. The mAb, SKS2v, recognized a gD antigen with an apparent molecular mass of 60kDa in a Western blot analysis. The isotype was determined by a sandwich ELISA to be IgG2a. HSV-2 exhibited major antigens of 36, 43, 46, 47, 60, 69, 81, 96, 109, 112, 159, and 227 kDa among 25 protein profiles in SDS-PAGE, and among these antigens, those of 60, 112, 125, and 227 kDa were immunodominant in a Western blot analysis using antisera, thereby indicating that they play a role in inducing neutralizing antibodies in HSV-2 infection. When reacted with Vero cells infected with HSV-1 and HSV-2 SKSv2 showed a reactivity to the surface of the infected cells, and a gD antigen of 60 kDa appeared to be expressed in both types of HSV.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.268-273
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• 2015

The fluorescent-antibody-to-membrane-antigen (FAMA) test is regarded as the "gold standard" to detect protective antibodies to varicella-zoster virus (VZV) because of its high sensitivity and specificity. Because the classic FAMA test uses an infectious virus for detection of antibodies to VZV, it is labor-intensive, and also requires special equipment for handling the virus. For this reason, we attempted to develop a simple and safe FAMA assay. Because VZV glycoprotein E (gE) is one of the major VZV glycoproteins, we used the gE protein for the FAMA test (gE FAMA). Here, we demonstrate that overexpression of gE in HEK293T cells can be used to measure antibodies in human serum, and that gE FAMA titers are closely correlated with gpEIA ELISA data. These results indicate that our gE FAMA test has the potential to measure antibodies to VZV.

• Korean Journal of Veterinary Research
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• v.35 no.4
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• pp.777-783
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• 1995

A monoclonal antibody(MAb), KCT-23ER, with specificity for E-rosetted T cells of Korean native cattle was prepared by cell hybridization of myeloma P3/NS-1/1-Ag-4-1 and spleen cells from BALB/c mice hyperimmunized with E-rosetted lymphocytes. The isotype of KCT-23ER to T lymphocytes was mouse $IgG_{2b}$. KCT-23ER was reacted with 53.6% to peripheral blood lymphocytes and with 67.8% to nylon wool nonadherent blood lymphocytes. And it was reacted with 72.2%, 59.2% and 35.3% to thymocytes, prescapular lymph node cells and splenocytes, respectively. Immunocytological reactive rates to E-rosetted and non-E-rosetted cells were 72.5% and 22.4%, respectively. These results indicated that KCT-23ER reacted to E-rosetted cells was one of the MAb for investigate of $CD_2$ receptor positive cell subset in the Korean native cattle.

• Korean Journal of Veterinary Research
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• v.35 no.4
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• pp.769-776
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• 1995

This study was undertaken to develop the monoclonal antibody(MAb) for lymphocytes of Korean native cattle by the cell hybridization of myeloma P3/NS-1/ 1-Ag-4-1 and spleen cells from BALB/c mice hyperimmunized with nylon wool column eluted peripheral T lymphocytes of Korean native cattle. The isotype of MAb KCT-14 against T lymphocyte was mouse $IgG_1$. KCT-14 positivity of mononuclear cells(MNC) from peripheral blood lymphocytes, nylon wool nonadherent and adherent-lymphocytes was 41.7%, 58.4% and 22.6%, respectively. And that of mesenteric lymph node-, spleen and thymus-MNC was 43.3%, 40.2% and 33.6%, respectively. Immunoperoxidase staining of frozen tissue sections showed that the MAb positive cells were located in the medulla of the thymus and in the paracortical area and the mantle zone of the germinal center in the lymph nodes. These results indicated that KCT-14 was one of the MAb for investigate of T lymphocyte subpopulations in the Korean native cattle.