• BMB Reports
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• v.48 no.9
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• pp.489-494
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• 2015

The in vitro antibody discovery technologies revolutionized the generation of target-specific antibodies that traditionally relied on the humoral response of immunized animals. An antibody library, a large collection of diverse, pre-constructed antibodies, can be rapidly screened using in vitro display technologies such as phage display. One of the keys to successful in vitro antibody discovery is the quality of the library diversity. Antibody diversity can be obtained either from natural B-cell sources or by the synthetic methods that combinatorially generate random nucleotide sequences. While the functionality of a natural antibody library depends largely upon the library size, various other factors can affect the quality of a synthetic antibody library, making the design and construction of synthetic antibody libraries complicated and challenging. In this review, we present various library designs and diversification methods for synthetic antibody library. From simple degenerate oligonucleotide synthesis to trinucleotide synthesis to physicochemically optimized library design, the synthetic approach is evolving beyond the simple emulation of natural antibodies, into a highly sophisticated method that is capable of producing high quality antibodies suitable for therapeutic, diagnostic, and other demanding applications. [BMB Reports 2015; 48(9): 489-494]

• Korean Journal of Pharmacognosy
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• v.19 no.2
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• pp.127-132
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• 1988

In the course of the immunological studies on the natural products, the antibody specific to saikosaponin a was producted. Saikosaponin a was treated with succinic anhydride to give 6'-O-hemisuccinyl saikosaponin a, which was successively converted to saikosaponin a-BSA conjugate (4. 5 mole saikosaponin a/mole of BSA) by carbodiimide method. The antibody obtained from rabbits immunized with saikosaponin a-BSA conjugate as usual manner reacted with both the conjugate and BSA, while after the absorption with BSA, the antibody reacted with the conjugate alone.

• The Journal of Korean Society of Virology
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• v.26 no.1
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• pp.101-106
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• 1996

Hantavirus is the etiologic agent of hemorrhagic fever with renal syndrome (HFRS). It has been known that the natural reservoirs of Hantavirus are not only field mice but also other animals in parts of the world. In this study, to research on the host range of Hantavirus, immunofluorescent antibody against Hantavirus was investigated in wild birds from 1991 to 1992, duck from 1991 to 1992 and squirrels (Tamias sibiricus) in 1990 in Korea. The results were as follows: 1. Of total 179 wild birds of 14 species, Emberiza elegans elegans and Passer montanus dy-bowsky were antibody positive. The positive rates were 3.92% (2 out of 51) and 1.64% (1 out of 61), respectively. 2. The antibody titers of wild birds were 1:16 and 1:64 in Emberiza elegans elegans, 1:16 in Passer montanus dybowsky. 3. The positive rate of antibody in ducks was 2.3% (3 out of 129). 4. The positive rate of antibody in squrrels was 48.10% (38 out of 79). According these results, we newly showed that passer montanus dybowsky, domestic ducks and Tamias sibiricus possessed the antibody against Hantavirus.

• Molecules and Cells
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• v.40 no.9
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• pp.655-666
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• 2017

We constructed a large $na{\ddot{i}}ve$ human Fab library ($3{\times}10^{10}$ colonies) from the lymphocytes of 809 human donors, assessed available diversities of the heavy-chain variable (VH) and ${\kappa}$ light-chain variable (VK) domain repertoires, and validated the library by selecting Fabs against 10 therapeutically relevant antigens by phage display. We obtained a database of unique 7,373 VH and 41,804 VK sequences by 454 pyrosequencing, and analyzed the repertoires. The distribution of VH and VK subfamilies and germline genes in our antibody repertoires slightly differed from those in earlier published natural antibody libraries. The frequency of somatic hypermutations (SHMs) in heavy-chain complementarity determining region (HCDR)1 and HCDR2 are higher compared with the natural IgM repertoire. Analysis of position-specific SHMs in CDRs indicates that asparagine, threonine, arginine, aspartate and phenylalanine are the most frequent non-germline residues on the antibody-antigen interface and are converted mostly from the germline residues, which are highly represented in germline SHM hotspots. The amino acid composition and length-dependent changes in amino acid frequencies of HCDR3 are similar to those in previous reports, except that frequencies of aspartate and phenylalanine are a little higher in our repertoire. Taken together, the results show that this antibody library shares common features of natural antibody repertoires and also has unique features. The antibody library will be useful in the generation of human antibodies against diverse antigens, and the information about the diversity of natural antibody repertoires will be valuable in the future design of synthetic human antibody libraries with high functional diversity.

• Journal of Microbiology
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• v.41 no.2
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• pp.137-143
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• 2003

The present study was performed to identify pathogenic factors of Chlamydia trachomatis, which invade the host cell membrane. We prepared monoclonal antibody against C. trachomatis and searched for pathogenic factors using this antibody, and subsequently identified the surface components of the elementary body of C. trachomatis, i.e., major outer membrane protein (MOMP), lipopolysaccharide (LPS), and two other surface exposure proteins. These proteins are believed to be important in the pathogenesis of host cell chlamydial infection. Additionally, to identify factors related to the host cell and C. trachomatis, we prepared C. trachomatis infected and non-infected McCoy cell extracts, and reacted these with anti-chlamydial LPS monoclonal antibody. We found that anti-chlamydial LPS monoclonal antibody reacted with a 116 kDa proteinaceous McCoy cell membrane component.

• Clinical and Experimental Vaccine Research
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• v.13 no.1
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• pp.63-67
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• 2024

This repeated cross-sectional study with two independent sample populations compared the antibody response to severe acute respiratory syndrome coronavirus 2 vaccines in Albania in July-August 2021 and 2022. In 2021, it found higher anti-spike-1 seropositivity and antibody levels in fully vaccinated individuals, especially with BNT162b2 and ChAdOx1 and to a lesser degree with CoronaVac. By 2022, all single-dose recipients showed high antibody responses, suggesting natural infection-enhanced immunity. The study indicates a significant evolution in the antibody response to different coronavirus disease 2019 vaccines and suggests that a single vaccine dose, coupled with natural infection, might suffice to maintain adequate immunity levels in an endemic scenario.

• YAKHAK HOEJI
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• v.41 no.1
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• pp.74-80
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• 1997

A polygonal antibody against recombinant hirudin was raised for the development of a ELISA in biological fluids. Recombinant hirudin was conjugated to maleimide activated carrie r protein, KLH and injected to a rabbit. The third booster collection of antiserum was used as primary antibody for the ELISA. The titer for the detection antibody was determined. The direct ELISA could determine the concentration of hirudin in the range of ~10ng/ml. Affinity pulified IgG was obtained and conjugated to horseradish peroxidase. Purified IgG and IgG-HRP could be used as capture and detection antibody, respectively. Although sandwich ELISA would not give the satisfactory results. it could apply for the detection of hirudin level in the range of ~20 ${\mu}$g/ml.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.328-334
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• 2011

Leucine zipper motif consists of multiple periodic leucine residues, which forms amphipathic alpha helix. The hydrophobic nature of leucine zipper motif can dimerize proteins which contain this motif. Leucine zipper motif addition at C-terminus of single-chain Fv (ScFv) antibody induces its dimerization. Since the dimeric ScFv antibody contains two antigen binding sites (bivalency) like Y-shaped complete antibody, it could increase avidity. As a result, it could show higher antigen binding activity than monomeric ScFv antibodies. Based on this concept, monomeric chicken 8C3 ScFv antibody previously developed from chicken hybridoma was dimerized by the addition of leucine zipper motif at C-terminus of ScFv antibody. The dimeric 8C3 ScFv antibody specifically reacted with Eimerian sporozoite which causes Avian Coccidiosis. As expected, dimeric 8C3 ScFv antibody showed 3-folds higher antigen binding activity than monomer due to increased avidity. In addition, protien yields of dimer expression were 2-folds higher than monomer.

• Animal cells and systems
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• v.4 no.4
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• pp.381-388
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• 2000

Using a murine T cell hybridoma, activation-induced cell death (AICD) was studied. As an in vitro model system for the AICD, 1 cell hybridoma expressing TCR/CD3 complex was incubated onto the immobilized purified anti-CD3 antibody. The immobilized anti-CD3 antibody induced AICD effectively up to 40%. At 1-100 $\mu$M range of SNP, an exogenous source of nitric oxide (NO), the cell proliferation was not affected, but at 1 mM SNP, cell proliferation was significantly reduced. The AICD of T cell hybridoma was inhibited by exogenous NO at non-cytotoxic concentration, In the cells undergoing AICD, the expressions of caspase-3 and FasL were detected, but not iNOS. Similar result was recognized in the apoptosis induced by dexamethasone, an apoptosis-inducing agent. However, the conversion from the inactive form of caspase-3 (32 kDa) to the active form (17 kDa) was significantly reduced in the cells in AICD induced by anti-CD3 antibody, With the result of increased PARP cleavage in the cells, we propose that another PARP cleavage pathway not involving caspase-3 may function in the anti-CD3 antibody induced AICD in the T cell hybridoma.

• The Journal of Korean Society of Virology
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• v.26 no.1
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• pp.91-99
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• 1996

To understand whether the bats inhabiting in Korea play role as hosts harboring Hantavirus that cause acute febrile diseases, a total number of 802 bats of 9 species were collected from seven provinces in Korea from 1989 to 1995 and tested for the presence of antibodies to Hantavirus by means of immunofluorescent antibody (IFA) technique. The results are summarized as follow. 1. Total 802 captured bats were classified into 9 different species with the following distribution. They were Rhinolophus ferrumequinum, Eptesicus serotinus, Miniopterus sehreibersii, Vespertilio superans, Myotis mystatinus, Murina leucogaster, Myotis formosus, Myotis macrodactylus and Plecotus auritus with numbers and rates of 423 (52.74%), 291 (36.28%), 47 (5.86%), 28 (3.49%), 8 (1.00%), 1 (0.12%) and 1 (0.12%), respectively. The predominant species of the bats was Rhinolophus ferrumequinum with 52.74% of the captured. 2. Among 9 species of bats, species of Rhinolophus ferrumequinum and Eptesicus serotinus were positive with Hantavirus antibody of strain numbers 76-118. The rate of antibody positive was 3.78%. 3. The seasonal differences of Hantavirus antibody in 802 bats tested were 5.83%, 4.17%, 3.67% and 0.64% in winter, spring, summer and autumn, respectively. Again the highest viral antibody prevalence was detected in winter. It could be concluded through the study that certain species of bats inhabiting in Korea play a definite role as the host animals of certain species of Hantavirus.