• BMB Reports
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• v.28 no.4
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• pp.353-358
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• 1995

Epitope tagging is the process of fusing a set of amino acid residues that are recognized as an antigenic determinant to a protein of interest. Tagging a protein with an epitope facilitates various immunochemical analyses of the tagged protein with a specific monoclonal antibody. The monoclonal antibody H8 has subtype specificity for an epitope derived from the preS2 region of hepatitis B virus surface antigen. Previous studies on serial deletions of the preS2 region indicated that the preS2 epitope was located in amino acid residues 130~142. To test whether the amino acid sequence in this interval is sufficient to confer on proteins the antigenicity recognizable by the antibody H8, the set of amino acid residues in the interval was tagged to the amino terminal of ${\beta}$-galactosidase and to the carboxyl terminal of the truncated $p56^{lck}$ fragment. The tagged ${\beta}$-galactosidase, expressed in Escherichia coli, maintained the enzymatic activity and was immunoprecipitated efficiently with H8. The tagged $p56^{lck}$ fragment, synthesized in an in vitro translation system, was also immunoprecipitated specifically with H8. These results demonstrate that the amino acid sequence of the preS2 region can be used efficiently for the epitope tagging approach.

• Journal of Life Science
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• v.8 no.5
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• pp.571-575
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• 1998

The nerve system specific protein of Drosophila melanogaster was produced by using heads of flies as the antigen. The monoclonal antibody 6H6 recognized the disabled molecules that a kind of tyrosine kinase substrate by expres-sion cDNA library screening method. At the same time, the antibody also specifically recognized C-terminal region of disabled protein from 7427 to 8761bp by DNA sequencing. In early embryos, the localization of antigen appeared in the central nerve system. In adult flies, the antigen showed specific localization on the axon of optic nerve, cerebral nerve and thoracic nerve, and they also expressed on the muscular nerve. The molecules of disabled are expected to carry an important function in developing central nerve system. In adult flies, it is suggested that the disabled molecules have a role for muscular nerve as well as neural axon.

• Korean Journal of Animal Reproduction
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• v.14 no.2
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• pp.107-114
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• 1990

These experiments were undertaken as a basic study to develop immunocontraceptive vaccine and to understand the role of zona pellucidae in early fertilization process by identifying the monoclonal and polyclonal antibody to porcine zona pellucidae and polyclonal antibody to mouse zona pellucidae by indirect ELISA and indirect immunofluorescence test. The results obtained in these experiments were summarized as follows : 1. The titer of the antibodies to zona was determined by indirect ELISA using solubilized porcine zona coated plates. Both monoclonal and rabbit polyclonal antibodies showed very high titers ; O.D at 1 : 12,800 dilution of antibodies was still significantly higher than that of non-immunized control serum. Rabbit anti-mouse zona pellucidae sera also reacted with porcine zona pellucidae. 2. By indirect immunofluorescence test strong fluorescences were observed on the egg treated with homologous and heterologous rabbit polyclonal antibodies and FITC lablled 2nd antibodies and found to crossreact strongly with the eggs from the pig and mouse. While weaken fluorescences were observed on the eggs treated with monoclonal antibodies.

• YAKHAK HOEJI
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• v.37 no.4
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• pp.420-426
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• 1993

To effectively purify of IL-1 inhibitor from human febrile urine, we have established monoclonal antibody that reacts with human recombinant interleukin l$\beta$(IL-1$\beta$). The antibody, designated ON-1, was highly specific to IL-1$\beta$ and no cross-reaction with other cytokines(IL-l$\alpha$ and IL-4) was observed. As the results of ELISA inhibition assay and Western blotting method, it was further identified that ON-1 had high binding specificity with IL-1$\beta$. IL-1 receptor binding material from febrile patient urine was effectively purified with affinity column chromatography which conjugated with ON-1. This urinary material inhibited the thymocyte proliferation in a dosedependent manner. IL-l$\beta$ induced thymocyte proliferation activity was inhibited to 67.3% at 6 $\mu\textrm{g}$ of the purified urinary material. The result may suggest that this urinary material the purified urinary material. The result may suggest that this urinary material will have antagonic effect on IL-1 action mechanism and act IL-l$\beta$ inhibitor.

• Journal of Microbiology
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• v.45 no.6
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• pp.572-577
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• 2007

To enhance therapeutic potential of murine monoclonal antibody, humanization by CDR grafting is usually used to reduce immunogenic mouse residues. Most humanized antibodies still have mouse residues critical for antigen binding, but the mouse residues may evoke immune responses in humans. Previously, we constructed a new humanized version (AKA) of mouse CC49 antibody specific for tumor-associated glycoprotein, TAG-72. In this study, to select a completely human antibody light chain against TAG-72, guided selection strategy using phage display was used. The heavy chain variable region (VH) of AKA was used to guide the selection of a human TAG-72-specific light chain variable region (VL) from a human VL repertoire constructed from human PBL. Most of the selected VLs were identified to be originated from the members of the human germline VK1 family, whereas the VL of AKA is more homologous to the VK4 family. Competition binding assay of the selected Fabs with mouse CC49 suggested that the epitopes of the Fabs overlap with that of CC49. In addition, they showed better antigen-binding affinity compared to parental AKA. The selected human VLs may be used to guide the selection of human VHs to get completely human anti-TAG72 antibody.

• IMMUNE NETWORK
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• v.3 no.4
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• pp.281-286
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• 2003

Background: Hepatitis B virus (HBV) infection is one of the worldwide public health problem affecting about 300 million people. The envelope protein of HBV consists of three components known as preS1, preS2, and S antigen. According to the recent study, anti-HBs Ab showed effective neutralization ability against HBV from chronic hepatitis B and liver transplant patients, suggesting the possible development of therapeutic antibody. Methods: Spleen cells immunized with S antigen of HBV were fused with myeloma cell line to obtain HBsAg specific monoclonal antibodies. High affinity antibodies against HBsAg (adr, ad and ay type) were selected by competitive ELISA method. Nucleotide sequence of the variable regions of monoclonal antibodies was analyzed by RT-PCR followed by conventional sequencing method. Results: We produced 14 murine monoclonal antibodies which recognize S antigen of HBV. Two of them, A9-11 and C6-9 showed the highest affinity. The sequence analysis of A9-11 revealed that variable regions of the heavy chain and light chains are members of mouse heavy chain I (B) and light chain lambda 1, respectively. Likewise, the sequence analysis of C6-9 revealed that variable regions of the heavy chain and light chains are members of mouse heavy chain II (B) and light chain kappa 1, respectively. Neutralization assay showed that A9-11 and C6-9 effectively neutralize the HBV infection. Conclusion: These results suggest that A9-11 and C6-9 mouse monoclonal antibodies can be used for the development of therapeutic antibody for HBV infection.

• IMMUNE NETWORK
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• v.4 no.1
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• pp.16-22
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• 2004

Background: To develop a novel treatment strategy for hepatitis B virus infection, a major cause of liver chirosis and cancer, we aimed to make human monoclonal antibodies inhibiting RNase H activity of P protein playing in important role in HBV replication. In this regard, phage display technology was employed and demonstrated as an efficient cloning method for human monoclonal antibody. So this study analysed the usability of human monoclonal antibody as protein based gene therapy. Methods: RNase H of HBV was expressed as fusion protein with maltose binding protein and purified with amylose resin column. Single chain Fv (scFv) phage antibody library was constructed by PCR cloning using total RNAs of PBMC from 50 healthy volunteers. Binders to RNase H were selected with BIAcore 2000 from the constructed library, and purified as soluble antibody fragment. The affinity and sequences of selected antibody fragments were analyzed with BIAcore and ABI automatic sequencer, respectively. And finally RNase H activity inhibiting assay was carried out. Results: Recombinant RNase H expressed in E. coli exhibited an proper enzyme activity. Naive library of $4.46{\times}10^9cfu$ was screened by BIAcore 2000. Two clones, RN41 and RN56, showed affinity of $4.5{\times}10^{-7}M$ and $1.9{\times}10^{-7}M$, respectively. But RNase H inhibiting activity of RN41 was higher than that of RN56. Conclusion: We cloned human monoclonal antibodies inhibiting RNase H activity of P protein of HBV. These antibodies can be expected to be a good candidate for protein-based antiviral therapy by preventing a replication of HBV if they can be expressed intracellularly in HBV-infected hepatocytes.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.727-727
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• 2005

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1327-1338
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• 2013

The humanized anti-hepatocyte growth factor (HGF) monoclonal antibody (mAb) YYB-101 is a promising therapeutic candidate for treating various cancers. In this study, we developed a bioprocess for large-scale production of YYB-101 and evaluated its therapeutic potential for tumor treatment using a xenograft mouse model. By screening diverse chemically defined basal media formulations and by assessing the effects of various feed supplements and feeding schedules on cell growth and antibody production, we established an optimal medium and feeding method to produce 757 mg/l of YYB-101 in flask cultures, representing a 7.5-fold increase in titer compared with that obtained under non-optimized conditions. The optimal dissolved oxygen concentration for antibody production was 70% $pO_2$. A pH shift from 7.2 to 7.0, rather than controlled pH of either 7.0 or 7.2, resulted in productivity improvement in 5 L and 200 L bioreactors, yielding 737 and 830 mg/ml of YYB-101, respectively. The YYB-101 mAb highly purified by affinity chromatography using a Protein A column and two-step ion exchange chromatography effectively neutralized HGF in a cell-based assay and showed potent tumor suppression activity in a mouse xenograft model established with human glioblastoma cells.

• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1605-1608
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• 2003

To development an immunodetection method for DDT, 1,1,1-trichloro-2,2-bis(4-chorophenyl)ethane (p,p'-DDT) and its metabolites (p,p'-DDA, p,p'-DDE, p,p'-DDD), five derivatives of DDT haptens have been synthesised and characterized as coating ligands for antibody evaluation. The appropriate lengths of linkers were introduced to investigate a matching pair of coating ligand and antibody. Among these hapten derivatives, 2,2-bis(4-chlorophenyl)acetic acid (DDA), 5,5-bis(4-chlorophenyl)-5-hydroxypentanoic acid (DDHP) and 5,5-bis(4-chlorophenyl)-5-chloropentanoic acid (DDCP) were conjugated with keyhole limpet hemocyanin (KLH) for its use as an immunogen. The bovine serum albumin (BSA) conjugates of these derivatives were prepared as a coating ligand for monoclonal antibody screening. Fifteen monoclonal antibody clones were screened using these probes. 6,6-Bis(4-chlorophenyl)-6-hydroxyhexanoic acid (DDHH) and 3-[6,6-Bis(4-chlorophenyl)-6-hydroxyhexanoylamino]propanoic acid (DDHHAP), in addition to the above hapten derivatives, were conjugated to ovualbumin (OVA) and bovine serum albumin (BSA) for their use as coating ligands to measure the titration level of the antibody and the displacement of free analytes. The indirect competitive ELISA results indicate that the titration level and free analyte displacement were greatly influenced by the DDT derivatives and carrier proteins used. Three matching pairs of monoclonal antibodies and coating ligands were selected for the DDT immunoassay: antibody clone 1A3 and coating ligand DDA-OVA, 1A1 and DDHHAP-BSA, and 1A4 and DDHP-OVA.