• Title/Summary/Keyword: antibody activity

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$Site-Specific^{99m}$Tc-Labeling of Antibody Using Dihydrazinoph-thalazine (DHZ) Conjugation to Fc Region of Heavy Chain

  • Jeong, Jae-Min;Lee, Jae-Tae;Paik, Chang-Hum;Kim, Dae-Kee;Lee, Dong-Soo;Chung, June-Key;Lee, Myung-Chul
    • Archives of Pharmacal Research
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    • v.27 no.9
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    • pp.961-967
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    • 2004
  • The development of an antibody labeling method with $^{99m}$Tc is important for cancer imaging. Most bifunctional chelate methods for $^{99m}$Tc labeling of antibody incorporate a $^{99m}$Tc chelator through a linkage to lysine residue. In the present study, a novel site-specific $^{99m}$Tc labeling method at carbohydrate side chain in the Fc region of 2 antibodies (T101 and rabbit anti-human serum albumin antibody (RPAb)) using dihydrazinophthalazine (DHZ) which has 2 hydrazino groups was developed. The antibodies were oxidized with sodium periodate to pro-duce aldehyde on the Fc region. Then, one hydrazine group of DHZ was conjugated with an aldehyde group of antibody through the formation of a hydrazone. The other hydrazine group was used for labeling with $^{99m}$Tc. The number of conjugated DHZ was 1.7 per antibody. $^{99m}$Tc labeling efficiency was 46-85% for T101 and 67∼87% for RPAb. Indirect labeling with DHZ conjugated antibodies showed higher stability than direct labeling with reduced antibodies. High immunoreactivities were conserved for both indirectly and directly labeled antibodies. A biodistribution study found high blood activity related to directly labeled T1 01 at early time point as well as low liver activity due to indirectly labeled T101 at later time point. However, these findings do not affect practical use. No significantly different biodistribution was observed in the other organs. The research concluded that DHZ can be used as a site-specific bifunctional chelating agent for labeling antibody with $^{99m}$Tc. Moreover, $^{99m}$Tc labeled antibody via DHZ was found to have excellent chemical and biological properties for nuclear medicine imaging.edicine imaging.

The Development of Dimerized Chicken Recombinant Single-chain Fv (ScFv) Antibody Using Leucine Zipper Motif (Leucine Zipper Motif를 이용한 닭의 재조합 이량체 Single-chain Fv (ScFv) 항체의 개발)

  • Park, Dong-Woon;Kim, Eon-Dong;Kim, Sung-Heon;Han, Jae-Yong;Kim, Jin-Kyoo
    • 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.

Studies on the Epitope of Neuronal Growth Inhibitory Factor (GIF) with Using of the Specific Antibody

  • Pang, Li-Yan;Ru, Bing-Gen
    • BMB Reports
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    • v.38 no.6
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    • pp.646-649
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    • 2005
  • Human neuronal growth inhibitory factor (GIF), a metalloprotein classified as metallothionein-3, is specifically expressed in mammal central nervous system (CNS). In these Studies the specific antibody to human GIF was prepared and used to search the epitope of human GIF by enzyme-linked immunosorbent assay (ELISA) and sequence comparison. The result of ELISA showed the epitope of human GIF may locate on a octapeptide (EAAEAEAE) in the $\alpha$-domain of human GIF, and the result of nerve cell culture indicated that the biological activity of GIF may be affected by the specific antibody.

Protein Array Fabricated by Microcontact Printing for Miniaturized Immunoassay

  • Lee Woo-Chang;Lim Sang-Soo;Choi Bum-Kyoo;Choi Jeong-Woo
    • Journal of Microbiology and Biotechnology
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    • v.16 no.8
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    • pp.1216-1221
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    • 2006
  • A protein array was fabricated for a miniaturized immunoassay using microcontact printing ($\mu$CP). A polydimethylsiloxane (PDMS) stamp with a 5 $\mu$m$\times$5 /$\mu$m dimension was molded from a silicon master developed by photolithography. Under optimal fabrication conditions, including the baking, incubation, and exposure time, a silicon master was successfully fabricated with a definite aspect ratio. An antibody fragment was utilized as the ink for the $\mu$CP, and transferred to an Au substrate because of the Au-thiol (-SH) interaction. The immobilization and antibody-antigen interaction were investigated with fluorescence microscopy. When human serum albumin (HSA) was applied to the protein array fabricated with an antibody against HSA, the detection limit was 100 pg/ml of HSA when using a secondary antibody labeled with a fluorescence tag. The fabricated protein array maintained its activity for 14 days.

Fractionated Aged Black Garlic Extracts Enhance Growth of Anti-My-10 Hybridoma Cells and Production of IgG1 Antibody

  • Lee, Ji Young;Chung, Namhyun;Lee, Yong Kwon
    • Journal of Applied Biological Chemistry
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    • v.57 no.1
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    • pp.61-63
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    • 2014
  • Aged black garlic (ABG) was extracted with 20% ethanol and water (crude extracts) and fractionated into three categories (>10, 3-10, and <3 kDa). The effect of crude extract supplements on anti-My-10 hybridoma cell growth and IgG1 antibody production was investigated in suspension culture with a chemically defined protein-free medium. We observed that supplementation of ABG to the cell culture medium stimulated anti-My-10 hybridoma cell growth and production of IgG1 antibody, particularly with fractionated ABG of low molecular weight. The stimulation depended upon the concentration and the size of the fractionated ABG. We also found that the growth-promoting activity was not correlated with high antibody production. These results suggest that fractionated ABG is a novel and promising alternative as an animal cell culture supplement.

Effect of Perilla Oil Diet on the Immune Response in Mice (마우스에 있어서 식이들기름이 면역반응에 미치는 영향)

  • 안영근;김정훈;김도훈
    • Environmental Analysis Health and Toxicology
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    • v.3 no.3_4
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    • pp.17-28
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    • 1988
  • The effects of perilla oil diet on the immune response in mice have been studied. ICR male mice were divided into 4 groups and were fed on the experimental diet for 4 weeks. Mice were sensitized and challenged with sheep red blood cell (S-RBC). Immune response were evaluated by antibody production, Arthus reaction, delayed type hypersensitivity (DTH), Rosette forming cell (RFC) and macrophage activity. The weight of body, liver, thymus and spleen were measured. The body weight was increased but thymus weight was not altered by them. The perilla oil diet decreased the weight of liver and spleen in mice. It reduced antibody production, Arthus reaction, DTH and RFC, macrophage activity. These results showed that the high perilla oil diet decresed more humoral and celluar immune response than the low perilla oil diet. It decreased the phagocytic activity on the reticuloendothelial system in mice.

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Studies on the Stability of Hen′s Egg Yolk Immunoglobulins (난황 항체의 안정성에 관한 연구)

  • 이경애
    • Korean journal of food and cookery science
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    • v.12 no.1
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    • pp.54-59
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    • 1996
  • Immunoglobulins (IgY) were isolated from egg yolk of hens immunized with bovine serum albumin(BSA). The stability of anti-BSA IgY against heat and pH was investigated. Antibody activity was measured by enzyme linked immunosorbent assay. IgY was relatively heat-stable and most of the antibody activity remained after heating up 65$^{\circ}C$ for 30 minutes. IgY was stable at pH 5-11. However, inactivation of IgY was observed below pH 4, or above pH 12. Inactivation of IgY proceeded rapidly at low pHs(pH 2-3). Most of the antigen binding activity was lost at low pHs probably because of some conformational changes.

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Properties of the Endonuclease Secreted by Human B Lymphoblastic IM9 Cells

  • Kwon, Hyung-Joo;Kim, Doo-Sik
    • BMB Reports
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    • v.31 no.1
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    • pp.106-110
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    • 1998
  • We have employed a DNA-native-polyacrylamide gel electrophoresis (DNA-native-PAGE) assay system to characterize the enzyme activity of the endonuclease secreted by human B lymphoblastic IM9 cells. Experimental results clearly demonstrated that the endonuclease activity of IM9 cell culture medium is distinct from that of DNase I in the DNA-native-PAGE assay system. Immunoprecipitation analysis using anti-DNase I antibody showed that the secreted endonuclease is not recognized by the antibody. The secreted endonuclease was estimated using supercoiled plasmid DNA as a substrate. The pH optimum required for the catalytic activity was determined to be in the range of pH 6.6-7.4. No significant difference in the endonuclease secretion was observed by stimulation of the IM9 cells with interferon-${\gamma}$ or interleukin-$1{\beta}$.

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A Generic Time-resolved Fluorescence Assay for Serine/threonine Kinase Activity: Application to Cdc7/Dbf4

  • Xu, Kui;Stern, Alvin S.;Levin, Wayne;Chua, Anne;Vassilev, Lyubomir T.
    • BMB Reports
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    • v.36 no.4
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    • pp.421-425
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    • 2003
  • The serine/threonine protein kinase family is a large and diverse group of enzymes that are involved in the regulation of multiple cellular pathways. Elevated kinase activity has been implicated in many diseases and frequently targeted for the development of pharmacological inhibitors. Therefore, non-radioactive antibody-based kinase assays that allow high throughput screening of compound libraries have been developed. However, they require a generation of antibodies against the phosphorylated form of a specific substrate. We report here a time-resolved fluorescence assay platform that utilizes a commercially-available generic anti-phosphothreonine antibody and permits assaying kinases that are able to phosporylate threonin residues on protein substrates. Using this approach, we developed an assay for Cdc7/Dbf4 kinase activity, determined the $K_m$ for ATP, and identified rottlerin as a non-ATP competitive inhibitor of this enzyme.

The p16INK4a Antibody Immobilization Method for Immonosensor Application

  • Yang, Li;Huang, Xian-He;Sun, Liang
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.12
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    • pp.5115-5118
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    • 2015
  • Background: The $p16^{INK4a}$ is a protein that expressed in Liquid-based cervical cytology specimens and has been proved link to cervical cancer. The $p16^{INK4a}$ could be detection by piezoelectric immunosensor and the immobilization of the $p16^{INK4a}$ antibody influence the sensitivity of the piezoelectric immunosensor. Materials and Methods: $5{\mu}L$ mouse polyclonal antibody against $p16^{INK4a}$ was bound onto the surface of immonosensor through two methods. (directly immobilized method; protein A method). Absorb of the $p16^{INK4a}$ antibody on the surface of immonosensor caused a shift in the resonant frequency of the immunosensor and The frequency changes recorded showed a better reproducibility. The activity of the immobilization antibody with the directly method and protein A method was tested with $p16^{INK4a}$ antigen. Results: The resonant frequency for different antibody immobilization methods were different, and the sensitivity for $p16^{INK4a}$ detection also different. Conclusions: The protein A method was found to be much more better than the directly method for the immobilization of the p16INK4A antibody on the gold electrode of the quartz crystal for cervical lesion detection. The Protein A method created more reproducible and stable immobilization antibody layers with p16INK4A antigen.