• Journal of Microbiology
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• v.39 no.1
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• pp.49-55
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• 2001

We have developed four chicken hybridomas secreting monoclonal antibodies to induce a protective immune response against the chicken disease avian coccidiosis, caused by the intestinal parasite Eimeria acervulina. Huwever, since the amount of antibodies secreted from these hybridomas is too low or sometimes they lost their ability to produce antibodies, the hybridoma method is not satisfactory in the production of large amounts of chicken monoclonal antibodies. To bypass these problems, we applied the antibody engineering technology using polymerase chain reaction. We cloned and determined the sequences of variable domains of the four chicken monoclonal antibodies, namely, 2-1, 5D11, 13C8 and 8C3. The sequences comparison to germline sequences skewed that the gene con version mechanism might contribute to developing diversification of heavy and λ-light chains in chicken antibodies. Several pseudogene families regarded as donors in gene conversion were identified at each framework region and the complementarily determining region of λ-light chains. In addition, as expected, numerous changes of nucleotide sequences such as nucleotide substitution, insertion and deletion were found predominantly in complementarity determining regions, which are likely to be somatic hypermutations as a result of affinity maturation in antibody-producing cells.

• BMB Reports
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• v.29 no.3
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• pp.192-199
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• 1996

A rapid and sensitive method has been developed to detect a-fetoprotein (AFP) in human serum by a two-site sandwich enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies (MAbs) for human AFP within 1 h. To obtain the most sensitive and reliable MAbs. 12 kinds of MAbs (HPJ1 to HPJ12) as a capture antibody and 4 kinds of horseradish peroxidase (HRP) conjugated MAbs as a tracer antibody were investigated. Among these, only HPJ 10-HRP conjugated HPJ 1 (HPJ 10-HPJ $1^*$) and HPJ 11-HRP conjugated HPJ 10 (HPJ 11-HPJ $10^*$) were chosen as candidates based on the linearity of the standard curve and the sensitivity of the assay. To further characterize these two pairs. MAbs against human AFP were purified from hybridoma cells. conjugated with HRP. and then characterized to optimize the two-site sandwich ELISA The HPJ 10-HPJ $1^*$ pair showed a sensitivity of 1 ng/ml and a better reproducibility than the HPJ 11-HPJ $10^*$ pair when the human sera were incubated at $37^{\circ}C$ for 30 min. The results obtained for 480 randomly selected human sera showed 0~20 ng/ml of AFP values for the normal human sera. To test the utility of our kit, AFP concentrations were determined for 951 human sera (including 85 normal sera, 480 random blood sera, 213 HBsAg-positives. 50 anti-HCV antibody positives. and 47 malignant diseases) and compared with other commercially available AFP detecting kits. These results show that the present two-site sandwich ELISA method is a rapid, sensitive, and reliable procedure for detecting AFP in human serum.

• The Plant Pathology Journal
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• v.22 no.1
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• pp.21-27
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• 2006

We immunized BALB/c mice with purified Cucumber green mottle mosaic virus isolate HY1 (CGMMV-HY1). Through the selection of positive clones that were grown on the HAT medium, four sensitive monoclonal clones (CG99-01, CG99-02, CG99-03, and CG99-04) were selected from 500 Hypoxanthine-guanine phosphoribosyltransferase positive hybridoma cells. Four sensitive clones of CGMMV-HYI were determined as IgM type of the subclass of mouse immunoglobulins Ig group. The titer of monoclonal antiserum against CGMMVHY1 was estimated 1:12,800 by the indirect ELISA. Although monoclonal antibodies (MAbs) from CG99-01 and from CG99-04 cross-reacted with Zucchini green mottle mosaic virus and Kyuri green mottle mosaic virus, MAb from the cell line CG99-03 was highly specific to CGMMV. No MAbs cross-reacted with Cucumber mosaic virus-Fny. Only CG99-04 reacted with Pepper mild mottle virus weakly and CG99-02 reacted with both CGMMV and KGMMV. CGMMV was detected from the rind of watermelon fruit by DAS-ELISA of CGMMV-HY1, but not from the flesh of watermelon. Average seed transmission rate of CGMMV in watermelon was $24\%$ from symptomatic watermelon collected from 5 regions of Gyeongnam province. CGMMV was detected by DAS-ELISA with specific MAb of CGMMVHY1 periodically from root stock, during the sequential process for nursery seedling in Haman. Necrotic spots on cotyledons of root stock seedling progressed to reveal the typical symptomatology on the primary leaves of scion upon grafting. Here, we have established MAb based ELISA system, which could accurately detect CGMMV from watermelon seeds, nursery seedlings, transplants and field samples from greenhouse or open out door field as well.

• Journal of Aquaculture
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• v.15 no.1
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• pp.7-13
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• 2002

Since 1993, the White Spot Syndrome Virus (WSSV) disease occurred in China among cultured shrimps resulting in mass mortality. Epizootiological surveys undertaken during the outbreak period of 1993-1994 indicated that all stages of Penaeus chinensis, P. japonicus and P. monodon were infected. Consequent to the transport of contaminated shrimp seedlings and seawater, the disease spread all over the farms of China. The disease was more rapidly transmitted at temperatures above $25^{\circ}C$. Challenge experiments showed the causative agent was highly virulent. White spots appeared on the carapace of both span-taneous and experimentally infected shrimps. Moribund shrimps contained turbid hemolymph, hypertrophied Iymphoid organ and a necrotic mid-gut gland. Electron microscopy showed the presence of viral particles in the gills, stomach, lymphoid organ, and epidermal tissue of the infected shrimp. The visions were slightly ovoid with an envelope and averaged 350 $\times$ 150 nm; nucleocapsids measured 375 $\times$ 157 nm. With discontinuous sucrose gradient of 35, 50 and 60% (w/v), the virus was separated from hemolymph of the infected shrimp. The estimated molecular weight of genomic DNA was 237 Kb with EcoR I, 247 Kb with Hind III and 241kb with Pst I. A total of 9 hybridoma colones secreting monoclonal antibodies (MAbs) were produced from mouse myeloma and spleen cells immunized with WSSV. The immunofluorescence assay of gill tissue showed that the MAbs reacted with diseased but not with healthy shrimp. The MAbs belonged to IgGl, IgG2b subclass and IgM class, all with kappa light Immune-electron-microscopy with colloidal gold marker showed the presence of 5 MAbs epitopes on the envelope and one on the capsid of the virus. Baculoviral mid-gut gland necrosis showed the specificity of the MAbs produced. For diagnosis 5 different methods were selected. Using Kimura primers for PCR, or MAbs for immunoblot, ELISA or FAT method, in situ hybridization was carried out to show the gene. All these methods detected WSSV in the organ samples of the diseased shrimp but not in healthy one.

• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.529-535
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• 2011

Single-chain variable fragment (scFv) is a fusion protein of the variable regions of the heavy (VH) and light (VL) chains of immunoglobulin, connected with a short linker peptide of 10 to about 20 amino acids. In this study, the scFv of a monoclonal antibody against the third domain of human CD4 was cloned from OKT4 hybridoma cells using the phage display technique and produced in E. coli. The expression, production, and purification of anti-CD4 scFv were tested using SDS-PAGE and Western blot, and the specificity of anti-CD4 scFv was examined using ELISA. A 31 kDa recombinant anti-CD4 scFv was expressed and produced in bacteria, which was confirmed by SDS-PAGE and Western blot assays. Sequence analysis proved the ScFv structure of the construct. It was able to bind to CD4 in quality ELISA assay. The canonical structure of anti-CD4 scFv antibody was obtained using the SWISS_MODEL bioinformatics tool for comparing with the scFv general structure. To the best of our knowledge, this is the first report for generating scFv against human CD4 antigen. Engineered anti-CD4 scFv could be used in immunological studies, including fluorochrome conjugation, bispecific antibody production, bifunctional protein synthesis, and other genetic engineering manipulations. Since the binding site of our product is domain 3 (D3) of the CD4 molecule and different from the CD4 immunological main domain, including D1 and D2, further studies are needed to evaluate the anti-CD4 scFv potential for diagnostic and therapeutic applications.

• BMB Reports
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• v.33 no.1
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• pp.92-95
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• 2000

The HIV-1 p24(202-221) sequence ETINNEEEWDRVHPV HAGP contains a B-cell epitope with the earliest immune response and the highest antibody titer against anti-mouse sera obtained by immunization with p24 antigens. A novel mouse monoclonal antibody (mAb) was generated against the immunodominant B-cell epitope of the HIV-1 p24 capsid protein, p24(202-221). BALB/c mice were immunized with the four branched multiple antigenic peptide (MAP) containing the HIV-1p24(202-221) sequence, and antibody-secreting hybridoma were produced by fusion of mouse splenocytes with P3X63Ag8.653, mouse myeloma cells. One clone which produced the antigen-specific mAb named KI-24 (Isotype IgG1, light chain: ${\kappa}$) was identified. mAb KI-24 was highly specific for both the p24(202-221) and p24 proteins when analyzed by ELISA and Western blotting. Since p24(202-221) also contains a cytotoxic T-lymphocyte epitope, this specfic peptide epitope and the monoclonal antibody with specific reactivity against the p24 protein and p24(202-221) can be used in peptide vaccine development and p24 antigen detection from HIV patients.

• BMB Reports
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• v.31 no.1
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• pp.58-63
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• 1998

In this study, a mouse monoclonal antibody (mAb) against gp41(584-618), the immunodominant epitope protein, was generated. For this purpose, BALB/c mice were immunized with double branched multiple antigenic peptides derived from the HIV-1 gp41(584-618) sequence, and antibody-secreting hybridoma were produced by fusion of mice splenocytes with SP2/0 myeloma cells. One clone producing an antigen specific mAb, termed KI-41(isotype IgG1) was identified, whose specific reactivity against gp41(584-618) could be confirmed by ELISA and Western blot analysis. Epitope mapping revealed the recognition site of the mAb KI-41 to be located around the sequence RILAVERYLKDQQLLG, which comprises the N-terminal region within the immunized gp41(584-618) peptied. Since this mAb recognizes this specific epitope within the HIV-1 gp41 without any cross-reactivity to other immunodominant regions in the HIV-2 gp35, KI-41 will provide some alternative possibilities in further applications such as the development of indirect or competitive ELISA for specific antibody detection in HIV-1 infection or for other basic researches regarding the role and function of HIV-1 gp41.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.4
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• pp.298-304
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• 2006

In this study, we establish a thin-layer chromatography (TLC) immunostaining method for detecting starfish gangliosides. A new monoclonal antibody (MAb) against AG-2, the major gangliosides molecular species of Acanthaster planci, was produced by fusing hybridoma with splenocytes immunized to liposomal AG-2. BALB/c male mice were injected with liposomal AG-2 antigen, and immunized. Their splenocytos were isolated and fused with hypoxanthine-aminopterine-thimidine (HAT)-sensitive mouse myeloma cells. Hybridomas producing MAb reactive to AG-2 were cloned using the limited dilution method. Established hybridomas were cultured in eRDF medium. Crude MAb produced from clone 8D4 was purified with a magnesium pyrophosphate column. Enzyme immunoassay and TLC immunostaining of AG-2 were performed using the purified MAb. Structurally related gangliosides did not cross-react with anti-AG-2 antibodies. The detection limit of TLC immunostaining was 50 ng of AG-2. The newly established immunostaining method was further developed for detecting AG-2 distribution and qualitative analysis in tissues and/or organs. Our results show that the majority of AG-2 is present in the stomach of male A. planci, while AG-2 is distributed not only in the stomach but also in the the pyloric caeca of female A. planci.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.197-208
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• 1987

Chlamydia trachomatis has now shown that this interesting intracellular parasite is a cause of nongonococcal urethritis, infantile pneumonia, pelvic inflammatory disease and epididymitis, in addition to lymphogranuloma venerum and inclusion conjunctivitis. There are several diagnostic methods for C. trachomatis, but the method using monoclonal antibody is the most sensitive and specific. The hybride cell were prepared by fusion of myeloma cell($P_3X_{63}\;Ag_8{\cdot}V_{653}$) of mouse and lymphocyte of mouse(BALB/c) that were immunized with formalin killed C. trachomatis serotype D. The cell mixtures after fusion were dispensed into 640 wells of the 96 well culture plates and continuously cultured in HAT medium for 2 weeks. The supernatants of culture media in 83(13%) wells were reacted with C. trachomatis, which were determined by enzyme-linked immunosorbent assay in 96 well microplate. The clones that secreted antibody to C. trachomatis were cloned by limiting dilution. Only six monoclones secreted antibody to C. trachomatis. The antibody titer of ascitic fluid that collected from same BALB/c mice bearing hybridoma cells was above 1:100,000. These monoclonal antibodies that were IgG reacted with elementary and reticulate bodies of all serotypes(Ba, D, E, F, G, H, J and LGV type-I) using ELISA and indirect immunofluorescence stain, but there were no cross reaction with other bacteria(coagulase negative Staphylococcus, Proteus and E. coli). We concluded these six monoclones secreted the same monoclonal antibody to C. trachomatis. The sensitivity and specificity of the monoclonal antibody compared with Microtrak(confirmatory test of C. trachomatis, Syva) was 100%, respectively.

• Korean Journal of Veterinary Service
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• v.43 no.4
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• pp.237-244
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• 2020

Porcine transmissible gastroenteritis (TGE) has been a significant cause of economic losses in pig farming industry since 1950s. Although transmissible gastroenteritis virus (TGEV) has declined in recent years, it should not be excluded because of its characteristics; the frequency of gene mutation, the mortality in piglets, and the possibility for sudden incidence. Therefore, the herd-level monitoring of the virus is important to prevent further circulation of TGE. The aim of this study is to develop a large-scale sandwich enzyme-linked immunosorbent assay (ELISA) with high specificity to rapidly detect TGEV in feces by using monoclonal antibodies (Mabs). The TGEV specific Mabs were produced in hybridoma cells. Among the Mabs belonged to the IgG class developed by this study, the final selected 8H6, 1B7, 4G3, and 1F8 were identified to have the neutralization ability against TGEV. The sandwich ELISA was established using 8H6 as a reporter antibody and 1B7 and the reported 5C8 as a capture antibody. The developed sandwich ELISA was able to distinguish TGEV from other pathogenic diarrheal agents (porcine rotavirus, porcine reovirus, porcine epidemic diarrhea virus (PEDV), E. coli, and C. perfringens) in tissue culture as well as fecal samples. And the detection rate of TGEV in feces was 80% compared with RT-PCR. The results suggested that the developed sandwich ELISA may be useful in the herd-level monitoring for effective preventive measures due to the early diagnosis of TGEV using a large amount of samples.