• IMMUNE NETWORK
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• 제1권1호
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• pp.7-13
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• 2001

Currently 18 monoclonal antibodies were approved by FDA for inj ection into humans for therapeutic or diagnostic purpose. And 146 clinical trials are under way to evaluate the efficacy of monoclonal antibodies as anti-cancer agents, which comprise 9 % of clinical trials in cancer therapy field. When considering a lot of disappointment and worries existed in this field during the past 15 years, this boom could be called as resurrection. Antibodies have several merits over small molecule drug. First of all it is easier and faster in development, as proper immunization of the target proteins usually raises good antibody response. The side effects of antibodies are more likely to be checked out in immunohistomchemical staining of whole human tissues. Antibody has better pharmacokinetics, which means a longer half-life. And it is non-toxic as it is purely a "natural drug. Vast array of methods was developed to get the recombinant antibodies to be used as drug. The mice with human immunoglobulin genes were generated. Fully human antibodies can be developed in fast and easy way from these mice through immunization. These mice could make even human monoclonal antibodies against any human antigen like albumin. The concept of combinatorial library was also actively adopted for this purpose. Specific antibodies can be screened out from phage, mRNA, ribosomal library displaying recombinant antibodies like single chain Fvs or Fabs. Then the coding genes of these specific antibodies are obtained from the selected protein-gene units, and used for industrial scale production. Both $na\ddot{i}ve$ and immunized libraries are proved to be effective for this purpose. In post-map arena, antibodies are receiving another spotlight as molecular probes against numerous targets screened out from functional genomics or proteomics. Actually many of these antibodies used for this purpose are already human ones. Through alliance of these two actively growing research areas, antibody would play a central role in target discovery and drug development.

• Journal of Microbiology and Biotechnology
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• 제27권5호
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• pp.965-974
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• 2017

The single-chain variable fragment (scFv) against lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a promising molecule for its potential use in the diagnosis and immunotherapy of atherosclerosis. Producing this scFv in several milligram amounts could be the starting point for further engineering and application of the scFv. In this study, the abundant expression of the anti-LOX-1 scFv was attempted using Escherichia coli (E. coli) and Brevibacillus choshinensis (B. choshinensis). The scFv had limited soluble yield in E. coli, but it was efficiently secreted by B. choshinensis. The optimized fermentation was determined using the Plackett-Burman screening design and response surface methodology, under which the yield reached up to 1.5 g/l in a 5-L fermentor. Moreover, the properties of the scFvs obtained from the two expression systems were different. The antigen affinity, transition temperature, and particle diameter size were 1.01E-07 M, $55.2{\pm}0.3^{\circ}C$, and 9.388 nm for the scFv expressed by B. choshinensis, and 4.53E-07 M, $52.5{\pm}0.3^{\circ}C$, and 13.54 nm for the scFv expressed by E. coli. This study established an efficient scale-up production methodology for the anti-LOX-1 scFv, which will boost its use in LOX-1-based therapy.

• Journal of Microbiology and Biotechnology
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• 제29권4호
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• pp.651-657
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• 2019

Although smallpox was eradicated in 1980, it is still considered a potential agent of biowarfare and bioterrorism. Smallpox has the potential for high mortality rates along with a major public health impact, eventually causing public panic and social disruption. Passive administration of neutralizing monoclonal antibodies (mAbs) is an effective intervention for various adverse reactions caused by vaccination and the unpredictable nature of emerging and bioterrorist-related infections. Currently, vaccinia immune globulin (VIG) is manufactured from vaccinia vaccine-boosted plasma; however, this production method is not ideal because of its limited availability, low specific activity, and risk of contamination with blood-borne infectious agents. To overcome the limitations of VIG production from human plasma, we isolated two human single-chain variable fragments (scFvs), (SC34 and SC212), bound to vaccinia virus (VACV), from a scFv phage library constructed from the B cells of VACV vaccine-boosted volunteers. The scFvs were converted to human IgG1 (VC34 and VC212). These two anti-VACV mAbs were produced in Chinese Hamster Ovary (CHO) DG44 cells. The binding affinities of VC34 and VC212 were estimated by competition ELISA to $IC_{50}$ values of $2{\mu}g/ml$ (13.33 nM) and $22{\mu}g/ml$ (146.67 nM), respectively. Only the VC212 mAb was proven to neutralize the VACV, as evidenced by the plaque reduction neutralization test (PRNT) result with a $PRNT_{50}$ of ~0.16 mg/ml (${\sim}1.07{\mu}M$). This VC212 could serve as a valuable starting material for further development of VACV-neutralizing human immunoglobulin for a prophylactic measure against post-vaccination complications and for post-exposure treatment against smallpox.

• Nuclear Medicine and Molecular Imaging
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• 제43권5호
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• pp.487-494
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• 2009

목적: 작은 크기의 재조합 단일사슬 항체는 빠른 혈중 제거율과 종양의 항체 집적율이 증가되는 등의 장점을 가지고 있다. 반면에 항체의 작은 크기는 방사성 또는 형광물질의 표지를 위한 킬레이터 결합에 중요한 아미노산 그룹의 감소를 의미하기도 한다. 본 연구에서는 단일사슬 lym-1 염기서열 C-말단에 lysine 아미노산 태그를 삽입하여 형광 물질의 직접표지 및 그 표지수율 증가를 확인하고자 하였다. 대상 및 방법: 대장균 pET-22b (+) 벡터에 재조합 된 lysine 삽입 단일사슬 lym-1유전자는 대장균 BL21 (DE3)에 형질전환하여 발현하였다. 생산된 lysine lym-1 항체는 Ni-NTA 컬럽과 분자량 컬럼을 사용해 정제하였고. 단백질 전기 영동과 western blot을 통해 확인하였다. lysine lym-1 항체에 방사성 동위원소인 I-124, I-125, I-131 과 Tc-99m를 표지하여 그 수율을 확인하였으며 유세포계측기를 사용해 형광물질인 FITC가 직접표지된 라이신 lym-1 항체의 면역반응성을 사람의 버킷 림프종 세포주인 Raji 세포주에서 면역반응성을 확인하였다. 결과 Lysine도입 단일사슬 lym-1 항체는 두 과정의 정제를 통하여 획득하였으며 그 크기는 약 48 KDa이었고, 방사성동위원소인 I-124, I-125, I-131과 Tc-99m의 표지수율은 각각 >99%, >99%, >95%, >99%로 확인되었다. 유세포계측을 통한 lysine 도입 단일사슬 lym-1항체의 면역반응성은 기존의 단일사슬 lym-1항체와 유사함을 확인하였다. 결론: 재조합 lym-1 항체에 형광 물질을 직접 표지하기 위한 lysine 아미노산의 도입은 항체의 면역반응성 감소를 최소화 시키면서 직접표지 수율을 증가시킬 수 있는 유용한 방법임을 확인하였다.

• IMMUNE NETWORK
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• 제4권1호
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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.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권2호
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• pp.173-177
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• 2006

In this study, a novel strategy was developed for the highly selective immobilization of proteins, using the polyhydroxyalkanoate (PHA) depolymerase substrate binding domain (SBD) as an active binding domain. In order to determine the appropriacy of this method for immunodiagnostic assays, the single-chain antibody (ScFv) against the hepatitis B virus (HBV) preS2 surface protein and the severe acute respiratory syndrome coronavirus (SARS-CoV) envelope protein (SCVe) were fused to the SBD, then directly immobilized on PH A-coated slides via microspotting. The fluorescence-labeled HBV antigen and the antibody against SCVe were then utilized to examine specific interactions on the PHA-coated surfaces. Fluorescence signals were detected only at the spotted positions, thereby indicating a high degree of affinity and selectivity for their corresponding antigens/antibodies. Furthermore, we detected small amounts of ScFv-SBD (2.7 ng/mL) and SCVe-SBD fusion proteins (0.6ng/mL). Therefore, this microarray platform technology, using PHA and SBD, appears generally appropriate for immunodiagnosis, with no special requirements with regard to synthetic or chemical modification of the biomolecules or the solid surface.

• Asian-Australasian Journal of Animal Sciences
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• 제25권8호
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• pp.1089-1095
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• 2012

Neonatal Fc receptor (FcRn) gene encodes a receptor that binds the Fc region of monomeric immunoglobulin G (IgG) and is responsible for IgG transport and stabilization. In this report, the 8,900 bp porcine FcRn genomic DNA structure was identified and putative FcRn protein included 356 amino acids. Alignment and phylogenetic analysis of the porcine FcRn amino acid sequences with their homologies of other species showed high identity. Tissues expression of FcRn mRNA was detected by real time quantitative polymerase chain reaction (Q-PCR), the results revealed FcRn expressed widely in ten analyzed tissues. One single nucleotide polymorphism (SNP) (HQ026019:g.8526 C>T) in exon6 region of porcine FcRn gene was demonstrated by DNA sequencing analysis. A further analysis of SNP genotypes associated with serum Classical Swine Fever Virus antibody (anti-CSFV) concentration was performed in three pig populations including Large White, Landrace and Songliao Black pig (a Chinese indigenous breed). Our results of statistical analysis showed that the SNP had a highly significant association with the level of anti-CSFV antibody (At d 20; At d 35) in serum (p = 0.008; p = 0.0001). Investigation of expression and polymorphisms of the porcine FcRn gene will help us in further understanding the molecular basis of the antibody regulation pathway in the porcine immune response. All these results indicate that FcRn gene might be regarded as a molecular marker for genetic selection of anti-CSFV antibody level in pig disease resistance breeding programmes.

• 한국동물학회지
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• 제22권4호
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• pp.141-152
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• 1979

고양이 백혈병 바이러스에서 reverse transcriptase를 분리하여 생화학적 및 면역학적 연구를 하였다. 분자량은 72,000이고, DNA polymerase와 RNase H의 활성은 0.05-1 mM $M_n^2+$와 50-80 mM KCl에서 가장 좋았다. DNA polymerase와 RNase H는 같은 단백질 분자에 있으며, chymotrypsin 처리로서 RNase H를 쪼개낼 수 있으며, 이 RNase H도 reverse transcriptase의 항체에 의해서 활성이 거의 억제 된다. Reverse transcriptase의 항체 결합위치와 활성을 내는 위치는 다른 것 같다.

• Journal of Animal Science and Technology
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• 제64권3호
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• pp.588-598
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• 2022

Despite vaccination, equine influenza virus (EIV) and equine herpesvirus (EHV) infections still cause highly contagious respiratory diseases in horses. Recently, concurrent vaccination with EIV and EHV was suggested as a new approach; however, there have been no reports of concurrent vaccination with recombinant canarypox EIV and inactivated EHV vaccines. In this study, we aimed to compare the EIV-specific immune responses induced by concurrent administrations of a recombinant canarypox EIV vaccine and an inactivated bivalent EHV vaccine with those induced by a single recombinant canarypox EIV vaccine in experimental horse and mouse models. Serum and peripheral blood mononuclear cells (PBMCs) were collected from immunized animals after vaccination. EIV-specific serum antibody levels, serum hemagglutinin inhibition (HI) titers, and interferon-gamma (IFN-γ) levels were measured by enzyme-linked immunosorbent assay, HI assay, and quantitative polymerase chain reaction, respectively. Concurrent EIV and EHV vaccine administration significantly increased IFN-γ production, without compromising humoral responses. Our data demonstrate that concurrent vaccination with EIV and EHV vaccines can enhance EIV-specific cellular responses in horses.

• Journal of Veterinary Science
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• 제21권2호
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• pp.22.1-22.9
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• 2020

Rabid raccoon dogs (Nyctereutes procyonoides koreensis) have been responsible for animal rabies in South Korea since the 1990s. A recombinant rabies vaccine strain, designated as ERAGS, was constructed for use as a bait vaccine. Therefore, new means of differentiating ERAGS from other rabies virus (RABV) strains will be required in biological manufacturing and diagnostic service centers. In this study, we designed two specific primer sets for differentiation between ERAGS and other RABVs based on mutation in the RABV glycoprotein gene. Polymerase chain reaction analysis of the glycoprotein gene revealed two DNA bands of 383 bp and 583 bp in the ERAGS strain but a single DNA band of 383 bp in the field strains. The detection limits of multiplex reverse transcription polymerase chain reaction (RT-PCR) were 80 and 8 FAID₅₀/reaction for the ERAGS and Evelyn-Rokitnicki-Abelseth strains, respectively. No cross-reactions were detected in the non-RABV reference viruses, including canine distemper virus, parvovirus, canine adenovirus type 1 and 2, and parainfluenza virus. The results of multiplex RT-PCR were 100% consistent with those of the fluorescent antibody test. Therefore, one-step multiplex RT-PCR is likely useful for differentiation between RABVs with and those without mutation at position 333 of the RABV glycoprotein gene.