• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.81-89
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• 2004

Tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and lymphotoxin-$\alpha$ (LT-$\alpha$, TNF-$\beta$) can initiate and perpetuate human diseases such as multiple sclerosis (MS), rheumatoid arthritis (RA), and insulin-dependent diabetes mellitus (IDDM). TNFs can be blocked by the use of soluble TNF receptors. However, since monomeric soluble receptors generally exhibit low affinity or function as agonists, the use of monomeric soluble receptors has been limited in the case of cytokines such as TNF-$\alpha$, TNF-$\alpha$, interleukin (IL)-1, IL-4, IL-6, and IL-13, which have adapted to a multi component receptor system. For these reasons, very high-affinity inhibitors were created for the purpose of a TNFs antagonist to bind the TNFR and trigger cellular signal by using the multistep polymerase chain reaction method. First, recombinant simple TNFR-Ig fusion proteins were constructed from the cDNA sequences encoding the extracellular domain of the human p55 TNFR (CD120a) and the human p75 TNFR (CD120b), which were linked to hinge and constant regions of human $IgG_1$ heavy chain, respectively using complementary primers (CP) encoding the complementary sequences. Then, concatameric TNFR-Ig fusion proteins were constructed using recombinant PCR and a complementary primer base of recombinant simple TNFR-Ig fusion proteins. For high level expression of recombinant fusion proteins, Chinese hamster ovary (CHO) cells were used with a retroviral expression system. The transfected cells produced the simple concatameric TNFR-Ig fusion proteins capable of binding TNF and inactivating it. These soluble versions of simple concantameric TNFR-Ig fusion proteins gave rise to multiple forms such as simple dimers and concatameric homodimers. Simple TNFR-1g fusion proteins were shown to have much more reduced TNF inhibitory activity than concatameric TNFR-Ig fusion proteins. Concatameric TNFR-Ig fusion proteins showed higher affinity than simple TNFR-Ig fusion proteins in a receptor inhibitor binding assay (RIBA). Additionally, concatameric TNFR-Ig fusion proteins were shown to have a progressive effect as a TNF inhibitor compared to the simple TNFR-Ig fusion proteins and conventional TNFR-Fc in cytotoxicity assays, and showed the same results for collagen induced arthritis (CIA) in mice in vivo.

• Parasites, Hosts and Diseases
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• 제30권1호
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• pp.33-42
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• 1992

자유생활 아메바인 Naegleria fowleri는 비강을 통해 인체에 들어와 출혈성 수막뇌염을 일으켜 감염된 사람의 대부분을 일주일 이내에 사망하게 하는 원충이다. 이 실험에서는 N. fowleri에 특이한 단세포군 항체를 만들어 이의 특성 및 그 이용 가능성을 알아보고자 하였다. 7 종류의 단세포군 항체(Nf 1, Nf 2, NE 256, Nf 279, Nf 27, Nf 154, Nf 137)를 제조하였는데 각각의 isotope은 IgGl이 두 종류(Nf 27, Nf 154), IgG3가 1 종류(Nf 137), IgA가 4 종류(Nf 1, Nf 2, Nf 256, Nf 279)이었다. 이들 항체를 N. fwoleri와 다른 종류의 아메바를 항원으로 하여 효소표식 면역검사법을 시행하여 Nf 1 및 Nf 256 항체를 제외한 5종류의 항체가 N. fowleri에 특이한 항체임을 확인하였다. 또한 간접 형광항체법을 통하여 NF 256 항체를 제외한 6 종류의 단세포군 항체가 세포막의 일부에 결합하였음을 관찰하였다. Nf 154 항체를 이용한 immunoperoxidase 염색에서도 세포막의 반응을 관찰하였다. 단세포를 항체가 N. fowleri를 응집시키는지 알아보고자 항체를 N. fowleri 영양형과 반응시켰더니 Nf 27 항 체를 제외한 5 종류의 단세포를 항체에 의해 응집이 일어남을 알 수 있었으며 응집된 덩 양형을 보체로 처리한 후 CGVS배지에서 배양하였더니 영양형의 증식이 억제되었다. 또한 2종류의 단세포군 항체(Nf 2, Nf 154)는 조직 세포(Chinese hamster ovary cell: CHO)에 대한 N.fowleri의 세포독성을 저하시켰다. 단세포군 항채와 반응하는 항원의 분자량을 알아보고자 EITB(Enzyme-linked immunoelectrotransfer blot)를 시행하였는데 Nf 279 항체는 25 kDa 및 28 kDa, Nf 154 항체는 43 kDa, N( 137 항체는 29 kDa에 해당되는 분획에서 항원항체반응을 나타내었다. 이상의 성적을 종합하면 N. fowleri에 대한 7종류의 IgG., IgG3 및 IgA 단세포군 항체를 생산하였다. 그중 Nf 256 항체를 제외한 6 종류는 N. fowleri이 세포막 성분중 28 kDa-43 kDa의 항원과 반응하는 특이한 항체임을 관찰할 수 있었다. 또한 이 단세포를 항체들은 영양형을 응집시키며, 시험관 내에서의 증식을 억제시키고 CHO 세포에 대한 N. fowleri의 세포 독성을 저하시키는 성질을 가지고 있음을 알 수 있었다.

• 생명과학회지
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• 제21권11호
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• pp.1652-1657
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• 2011

혈액세포의 분화와 성장은 20 여종 이상의 성장인자에 의해 조절된다. 혈액세포 생산에 관여하는 인자를 조혈 성장인자(hematopoitic growth factor)라고 한다. 조혈성장인자를 임상적으로 사용하기 위해 원핵생물 또는 진핵 생물 생산 시스템에서 재조합 단백질로 생산되고 있다. 그 중에서 Glranulocyte-Colony Stimulating Factor(G-CSF)는 호중구 세포 수가 감소된 암환자와 선천성 질병을 가진 환자에게 임상적 치료제로 아주 중요한 역할을 한다. 이 환자들은 충분하지 못한 호중구 세포로 말미암아 감염에 대한 위험이 아주 높으며 치사율 또한 높다. 두 종류의 재조합 G-CSF가 항암치료 후 발생하는 부작용으로 나타나는 호중구 세포 감소증 치료에 사용되고 있다. G-CSF의 중요성에 맞추어 G-CSF의 물리적 및 생물학적 기능에 대한 특성을 설명하였으며, 또한 항암치료와 G-CSF의 임상적 사용에 대한 연관성을 토론하였다. 마지막으로 두 종류의 재조합 G-CSF인 non-glycosylated G-CSF, filgrastim과 glycosylated G-CSF를 비교 설명하였으며, 이들 기존의 G-CSF에 비교되는 바이오시밀러에 대한 전망을 제시하였다.

• Archives of Pharmacal Research
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• 제24권2호
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• pp.136-143
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• 2001

Fumonisins are specific inhibitors of ceramide synthase in sphingolipid metabolism. An alteration in sphingolipid metabolism as a result of fumonisin exposure is related to cell death (Yoo et al., 1992). The objective of this study was to investigate whether elevated free sphinganine levels are related to the sensitivity of cultured cells to fumonisin exposure. Fumonisin $B_1$ elevated the intracellular free sphinganine concentraions in both LLC-$PK_1$ and Chinese hamster ovary (CHO) cells. However, CHO cells are resistant to fumonisin cytotoxicity at 50${u}m$, while LLC-$PK_1$ cells are sensitive at concentrations greater than 357M. The intracellular concentration of free sphinganine in LLC-$PK_1$ cells treated at 50${u}m$ fumonisin $B_1$ for 72 h was approximately 1450 pmol/mg protein relative to the 37 pmol observed in the control culture. Under the same conditions, the population of apoptotic cells in the 50${u}m$ fumonisin $B_1$-treated culture was approximately 37% of the total compared to 12% in the control. The caspase III-like activity after 72 h in the 50${\mu}$M fumonisin $B_1$-exposed culture Increased to approximately 50 $pmol/mg$ protein/hr compared to 6 $pmol/mg$ protein/hr in the control. L-cycloserine, a serine palmitoyltransferase inhibitory reduced the fumonisin $B_1$-stimulated caspase III-like activity down to the control level. Under the same culture conditions, the intracellular concentration of free sphinganine after-cycloserine plus fumonisin $B_1$ treatment was 140 pmol/mg protein compared to 1450 $pmol/mg$ protein in fumonisin $B_1$ alone. The intracellular concentration of free sphinganine in CHO cells treated with 50${u}m$ fumonisin $B_1$ for 72 h was al)proximately 460 pmol/mg protein, indicating that the mass amount of elevated free sphinganine in the CHO cells was about 32% of that in LLC-$PK_1$ cells. Adding exogenous sphinganine to the CHO cells along with 50${u}m$ fumonisin $B_1$ treatment for 72 h caused both necrosis and apoptosis. In conclusion, the elevated endogenous sphinganine acts as a contributing factor to the fumonisin-induced cell death.

• Molecules and Cells
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• 제19권1호
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• pp.114-123
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• 2005

Nitropyrene, the predominant nitropolycyclic hydrocarbon found in diesel exhaust, is a mutagenic and tumorigenic environmental pollutant that requires metabolic activation via nitroreduction and ring oxidation. In order to determine the role of ring oxidation in the mutagenicity of 1-nitropyrene, its oxidative metabolites, 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide, were synthesized and their mutation spectra were determined in the coding region of hprt gene of CHO cells by a PCR amplification of reverse-transcribed hprt mRNA, followed by a DNA sequence analysis. A comparison of the two metabolites for mutation frequencies showed that 1-nitropyrene 9,10-oxide was 2-times higher than 1-nitropyrene 4,5-oxide. The mutation spectrum for 1-nitropyrene 4,5-oxide was base substitutions (33/49), one base deletions (11/49) and exon deletions (5/49). In the case of 1-nitropyrene 9,10-oxide, base substitutions (27/50), one base deletions (15/50), and exon deletions (8/50) were observed. Base substitutions were distributed randomly throughout the hprt gene. The majority of the base substitutions in mutant from 1-nitropyrene 4,5-oxide treated cells were $A{\rightarrow}G$ transition (15/33) and $G{\rightarrow}A$ transition (8/33). The predominant base substitution, $A{\rightarrow}G$ transition (11/27) and $G{\rightarrow}A$ transition (8/27), were also observed in mutant from 1-nitropyrene 9,10-oxide treated cells. The mutation at the site of adenine and guanine was consistent with the previous results, where the sites of DNA adduct formed by these compounds were predominant at the sites of purines. A comparison of the mutational patterns between 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide showed that there were no significant differences in the overall mutational spectrum. These results indicate that each oxidative metabolite exhibits an equal contribution to the mutagenicity of 1-nitropyrene, and ring oxidation of 1-nitropyrene is an important metabolic pathway to the formation of significant lethal DNA lesions.

• Journal of Ginseng Research
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• 제12권2호
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• pp.104-113
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• 1988

여러가지 농도의 cholesterol을 함유한 배지에서 배양한 CHO 세포내로 흡입된 cholesterol 양을 조사한 결과 흡입량이 배지의 cholesterol 농도에 비례하였으므로 cholesterol 흡입은 확산에 의한 것으로 생각된다. $^{125}I$으로 표지된 저밀도 지방단백질($^{125}I$-LDL)을 이용하여 여러가지 농도의 cholesterol을 함유한 배지에서 배양한 CHO 세포와 cholesterol이 없는 정상배지에서 배양한 CHO 세포에서의 LDL 수용체의 합성양상을 조사한 결과 배지에 가해준 cholesterol이 LDL 수용체 합성을 억제함을 확인하였다. Cholesterol의 LDL 수용체 생합성 억제작용에 미치는 ginsenoside의 영향을 조사하기 위해 ginsenoside와 cholesterol을 함께 함유한 배지에서 배양한 CHO 세포(시험군)과 cholesterol만을 포함한 배지에서 배양한 CHO 세포(대조군)에서의 LDL 수용체의 활성양상을 분석한 결과 대조군에 비해 시험군에서의 LDL 수용체 활성이 크게 증가하였다. RNA 및 단백질 합성도 시험군이 대조군보다 증가하였음을 관찰하였다. 그러나 이와 같은 실험조건하에서의 대조군과 시험군의 cholesterol농도를 측정한 결과 시험군의 cholesterol 농도가 대조군보다 훨씬 저하되고 있었다. Ginsenoside의 cholesterol농도 저하작용을 관찰하기 위해 CHO세포에서의 cholesterol의 steroid hormone(estradiol, progesterone)으로의 전환에 미치는 ginsenoside의 영향을 조사한 결과 ginsenoside는 cholesterol의 hormone으로의 전환을 촉진하였음이 확인되었다. 위와 같은 실험결과로 볼 때 ginsenoside는 CHO 세포내부에서의 cholesterol의 LDL 수용체 합성억제를 완화시켜 주는 것이라고 생각된다.

• Molecules and Cells
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• 제22권3호
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• pp.343-352
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• 2006

Sialic acid is a sugar typically found at the N-glycan termini of glycoproteins in mammalian cells. Lec3 CHO cell mutants are deficient in epimerase activity, due to a defect in the gene that encodes a bifunctional UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE). Sialic acid modification on the cell surface is partially affected in these cells. We have mutagenized Lec3 CHO cells and isolated six mutants (termed C2m) deficient in the cell surface expression of polysialic acid (PSA). Mutant C2m9 was partially defective in expression of cell-surface PSA and wheat germ agglutinin (WGA) binding, while in the other five mutants, both cell-surface PSA and WGA binding were undetectable. PSA expression was restored by complementation with the gene encoding the CMP-sialic acid transporter (CST), indicating that CST mutations were responsible for the phenotypes of the C2m cells. We characterized the CST mutations in these cells by Northern blotting and RT-PCR. C2m9 and C2m45 carried missense mutations resulting in glycine to glutamate substitutions at amino acids 217 (G217E) and 256 (G256E), respectively. C2m13, C2m39 and C2m31 had nonsense mutations that resulted in decreased CST mRNA stability, and C2m34 carried a putative splice site mutation. PSA and CD15s expression in CST-deficient Lec2 cells were partially rescued by G217E CST, but not by G256E CST, although both proteins were expressed at similar levels, and localized to the Golgi. These results indicate that the novel missense mutations isolated in this study affect CST activity.

• 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.

• Biomolecules & Therapeutics
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• 제30권6호
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• pp.529-539
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• 2022

Rheumatoid arthritis (RA) is a multifactorial immune-mediated disease, the pathogenesis of which involves different cell types. T-cell activation plays an important role in RA. Therefore, inhibiting T-cell activation is one of the current therapeutic strategies. Cytotoxic T-lymphocyte antigen 4-immunoglobulin (CTLA4-Ig), also known as abatacept, reduces cytokine secretion by inhibiting T-cell activation. To achieve a homeostatic therapeutic effect, CTLA4-Ig has to be administered repeatedly over several weeks, which limits its applicability in RA treatment. To overcome this limitation, we increased the number of sialic acid-capped antennas by genetically engineering the CTLA4 region to increase the therapeutic effect of CTLA4-Ig. N-acetylglucosaminyltransferase (GnT) and α2,6-sialyltransferase (α2,6-ST) were co-overexpressed in Chinese hamster ovary (CHO) cells to generate a highly sialylated CTLA4-Ig fusion protein, named ST6. The therapeutic and immunogenic effects of ST6 and CTLA4-Ig were compared. ST6 dose-dependently decreased paw edema in a mouse model of collagen-induced arthritis and reduced cytokine levels in a co-culture cell assay in a similar manner to CTLA4-Ig. ST6- and CTLA4-Ig-induced T cell-derived cytokines were examined in CD4 T cells isolated from peripheral blood mononuclear cells after cell killing through irradiation followed by flow- and magnetic-bead-assisted separation. Interestingly, compared to CTLA4-Ig, ST6 was substantially less immunogenic and more stable and durable. Our data suggest that ST6 can serve as a novel, less immunogenic therapeutic strategy for patients with RA.

• 사물인터넷융복합논문지
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• 제9권3호
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• pp.27-33
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• 2023

본 연구에서는 Diospyros kaki Thunb(감)의 염색 패턴으로 분석하여 매염제에 따라 견직물과 세포의 염색 패턴이 어떻게 변화하는지 수치적으로 평가하고자 하였다. 염색된 견직물이 충분히 건조되었을 때 견직물은 엷은 황색을 띠는 것으로 나타났다. 흥미롭게도 철 II 황산염 매염제는 색 변화를 가장 많이 변화시켰고, 견직물은 갈색 또는 암자색에 가까운 색으로 염색되었다. 수치해석을 위해 타르타르산 나트륨과 구연산 및 아세트산 구리에의해 각각 19%와 62.5%의 색상 변화가 유도될 수 있었다. 철 II 황산염은 무처리 매염제보다 88%로 가장 큰 차이를 보였다. 중국 햄스터 난소(CHO) 세포의 약 5% 및 10%는 각각 타르타르산나트륨과 시트르산 및 아세트산구리로 염색되었다. 철 II 황산염에 의해 유도된 염색 효과는 타르타르산 나트륨 + 시트르산에 의한 염색 효과보다 약 2.4배 더 높았다. 기존의 연구들에서는 염색 결과를 육안적으로 확인하여왔다. 하지만, 본 논문의 결과들은 염색을 육안적으로 확인할 뿐만아니라 색상변화를 수치화한 것이다. 특히, 빅데이터에 수치화된 결과들이 계속 집약 된다면 방법에서, 시간, 부피 등을 변화시키더라도 유사한 결과들을 어느 연구자들이 쉽게 얻을 수 있을 것이다. 또한, 본 연구의 수치 데이터는 IoT 구축 및 컴퓨터 분석을 위한 데이터베이스 구축에 중요한 근거가 될 수 있을 것으로 사료된다.