• 대한방사성의약품학회지
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• 제1권1호
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• pp.38-45
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• 2015

Most tumors are believed to overexpress several receptors, and small peptides targeting these receptors were developed for diagnosis and tumor therapy during past decade. Here we report that fibroadenoma can be visualized by bladder cancer specific peptide. A 9-mer bladder cancer specific peptide, which was discovered from the phage display method, was synthesized by peptide synthesizer, and additional tyrosine was conjugated at the N-terminal for radioiodination (Y-BP). Y-BP was radiolabeled with $^{131/124}I$ using Iodogen tube. The rat treated with N-butyl-N-(4-hydroxybutyl)nitrosamine for 8 weeks was allowed to grow until large size tumor was developed under axilla. The tumor model was microPET imaged sequentially using [$^{18}F$]FDG and radioiodinated $^{124}I-Y-BP$. The tumor was excised and examined by immunostaining studies. Radioiodinated $^{124}I-Y-BP$ was purified using fast protein liquid chromatography (FPLC) in > 90% radiochemical purity. The whole tumor was well visualized by [$^{18}F$]FDG with several intense focal uptake within tumor. The tumor was also clearly seen with $^{124}I-Y-BP$ at 4 h post-injection, and to our surprise the tumor uptake of $^{124}I-Y-BP$ lasted up to three days. The tumor was diagnosed histologically as a fibroadenoma derived from mammary gland. In conclusion, the bladder cancer specific peptide showed the good potential as a new radiotracer for the detection of breast fibroadenoma.

• 폴리머
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• 제38권4호
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• pp.550-556
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• 2014

펩타이드-고분자 하이브리드 소재(PPs)들은 선택적 용매에서 나노구조 형성을 위한 잠재적 구성 요소로서 많은 연구분야에 이용되고 있다. PPs는 잘 정의된 펩타이드-고분자로 이루어진 바이오콘주게이트의 손쉬운 제조방법과 다양한 응용분야에서 이들의 고유활성도에 대한 연구는 중요한 이슈이다. 본 연구에서는 atom transfer radical polymerization(ATRP)와 고체상 펩타이드 합성법을 이용하여 펩타이드-고분자 하이브리드 소재를 제조하였다. PYGK(proline-tyrosine-glycine-lysine) 펩타이드를 제조하기 위하여 일반적인 고체상 펩타이드 합성법을 이용하였다. PYGK 펩타이드는 섬유소용해(fibrinolysis) 과정에서 플라스미노젠과 반응하는 PFGK(proline-phenylalanine-glycine-lysine)와 유사한 펩타이드이다. 펩타이드와 펩타이드 개시제는 MALDI-TOF와 $^1H$ NMR을 이용하여 분석하였다. 펩타이드-고분자인 pSt-PYGK는 GPC, IR, $^1H$ NMR 분석법, 그리고 TLC를 이용하여 분석하였다. 구형 마이셀 집합체는 TEM과 SEM으로 측정하였다. 본 합성방법은 고유결합 활성도를 가진 잘 정의된 펩타이드-고분자 하이브리드 소재를 합성할 수 있는 기회를 제공한다.

• IMMUNE NETWORK
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• 제3권4호
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• pp.295-301
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• 2003

Background: Carcinoembryonic antigen (CEA) is well-known soluble tumor marker frequently detectable in peripheral blood of carcinoma patients and considered as good target for antigen-specific immunotherapy. In this study, we used a replication-deficient adenovirus containing CEA to study CTL induction in vitro after adenovirus-mediated gene transfer into DC. Methods: DC were obtained from mouse bone marrow and cultured with IL-4 and GM-CSF. For measuring CTL activity, splenocytes were harvested from the mice, which were immunized with DC that had been infected AdV-CEA or pulsed with CEA peptide. Untreated DC was used as a control. Splenocytes were re-stimulated in vitro with DC pulsed with CEA peptide for 7 days and CTL activity with CEA peptide-pulsed EL-4 cells were assessed in a standard $^{51}Cr$-release assay. The frequencies of antigen-specific cytokine-secreting T cell were determined with $mIFN-{\gamma}$ELISPOT. Results: DC infected with recombinant adenovirus expressing CEA induced CEA-specific CTL responses in vivo. Splenocyte induced from mice immunized with AdV-CEA-infected DC increase in the number of $IFN-{\gamma}$ secreting T cells compared with those from mice immunized with CEA peptide-pulsed DC. Conclusion: These results suggested that DC infected with recombinant adenovirus has advantages over other forms of vaccination and could provide an alternative approach vaccination therapies.

• Journal of Pharmaceutical Investigation
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• 제22권4호
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• pp.251-266
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• 1992

A major problem with the peptide-based drugs is that these drugs must generally be administered by injection. Therefore, there is considerable research interest in alternative routes of delivery, such as buccal, nasal, gastrointestinal route and etc. Site-specific drug delivery to the colon, as an alternative to parenteral drug delivery, is of interest for the delivery of peptide-based drugs as well as the delivery of low molecular weight drugs for the treatment of colonic disease, This review describes some considerations of colon-specific drug delivery using hydrogels.

• 대한수의학회지
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• 제25권1호
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• pp.7-17
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• 1985

Many investigators have been pursuing various attempts so far to produce hepatitis B surface antigen(HBsAg) vaccines using the techniques such as isolation from plasma of chronic HBsAg carrier, recombinant DNA technique or preparation of synthetic peptides specific for immunogenic determinants. Hepatitis B virus can not grow on any cell lines by the tissue culture technique at the present time. The plasma of chronic HBsAg carrier is expensive and its source is limited. The HBsAg from the recombinant DNA technique gave still very low yield. Another approach, therefore, has been initiated to develop a synthetic hepatitis B virus vaccine. The possible use of several distinct synthetic vaccines in prophylaxis can be facilitated by availability of full synthetic immunogens. Peptides synthesized for potential application as antiviral vaccines have been mostly tested in the form of conjugates with carrier proteins, although the free synthetic peptide can be immunogenic. To understand basic knowledges on the antigenicity and immunogenicity of a synthetic peptide specific for major immunogenic determinant of HBsAg, a nonapeptide, $H_2N^{139}Cys-Thr-Lys-Pro-Thr-Asp-Gly-^{146}Asn-Aba$ COOH, which corresponds to HBsAg amino acid residues 139 to 147, was synthesized by the Merrifield's solid-phase method with a slight modification. The antigenicity and immunogenicity of this specific synthetic peptide were examined comparing with purified plasma-derived natural HBsAg. The results obtained are as follows; 1. The peptide synthesized showed the identical amino acid composition to the theoretical value. The degree of purification and molecular weight were acertained by methods of high performance liquid chromatography and mass spectrometry. 2. Using m-maleimidobenzoyl-N-hydroxysuccinimide ester as a conjugating agent, the synthetic peptide was conjugated to rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin. Their conjugation yields were 8.3, 9.5, 15.8, 13.5, and 11.2%, respectively. 3. The natural HBsAg was purified from plasma of chronic HBsAg carrier. By the electron microscopic observation of the purified natural HBsAg preparation, no Dane particles were observed and the preparation showed negative DNA polymerase activity. 4. Antigenicity of the synthetic peptide and the plasma-derived natural HBsAg was determined by competition radioimmunoassay using $^{125}I$-natural HBsAg. Their 50% inhibitions appeared as $90{\mu}g/ml$ and $0.12{\mu}g/ml$ for the synthetic peptide and the natural HBsAg, respectively. This indicates that the former was about 750-fold less antigenic than the latter. 5. Immunogenicity of the synthetic peptide was determined by administering the peptide-carrier conjugates into rabbits with and without Freund's complete adjuvant. Regardless the carrier proteins and adjuvant, positive immune responses to the synthetic peptide were observed. The higher antibody titers, however, were shown in the groups administered with Freund's complete adjuvant. 6. Immunizing dose 50% in mice of the various peptide-carrier conjugates was 5.47, 6.00, 65.16, 31.25 and $13.03{\mu}g/dose$ for rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin, respectively, while the natural HBsAg showed $0.65{\mu}g/dose$. 7. It was postulated that homologous proteins prefer to heterologous ones as the carriers.

• BMB Reports
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• 제49권6호
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• pp.331-336
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• 2016

In murine collagen-induced arthritis (CIA), self-reactive T cells can recognize peptide antigens derived from type-II collagen (CII). Activation of T cells is an important mediator of autoimmune diseases. Thus, T cells have become a focal point of study to treat autoimmune diseases. In this study, we evaluated the efficacy of recombinant MHC class II molecules in the regulation of antigen-specific T cells by using a self peptide derived from CII (CII260-274; IAGFKGEQGPKGEPG) linked to mouseI-A^q in a murine CIA model. We found that recombinant I-A^q/CII260-274 molecules could be recognized by CII-specific T cells and inhibit the same T cells in vitro. Furthermore, the development of CIA in mice was successfully prevented by in vivo injection of recombinant I-A^q/CII260-274 molecules. Thus, treatment with recombinant soluble MHC class II molecules in complex with an immunodominant self-peptide might offer a potential therapeutic for chronic inflammation in autoimmune disease such as rheumatoid arthritis.

• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1765-1771
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• 2007

A polymerase chain reaction (PCR)-based method was developed to detect the DNA of Ralstonia solanacearum, the causal agent of bacterial wilt in various crop plants. One pair of primers (RALSF and RALSR), designed using cytochrome c1 signal peptide sequences specific to R. solanacearum, produced a PCR product of 932 bp from 13 isolates of R. solanacearum from several countries. The primer specificity was then tested using DNA from 21 isolates of Ralstonia, Pseudomonas, Burkholderia, Xanthomonas, and Fusarium oxysporum f. sp. dianthi. The specificity of the cytochrome c1 signal peptide sequences in R. solanacearum was further confirmed by a DNA-dot blot analysis. Moreover, the primer pair was able to detect the pathogen in artificially inoculated soil and tomato plants. Therefore, the present results indicate that the primer pair can be effectively used for the detection of R. solanacearum in soil and host plants.

• 농업과학연구
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• 제41권3호
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• pp.237-243
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• 2014

Human Glucagon like peptide-1 (GLP-1) is an incretin hormone that promotes secretion of insulin. In order to eliminate the formation of the soluble aggregate, Ala19 in GLP-1 was substituted with Thr, resulting in a GLP-1 mutant GLP-1A19T. The gene synthesis of GLP-1A19T and the fusion of 6-lysine tagged ubiquitin gene were accomplished by using the overlap extension polymerase chain reaction. The ubiquitin fused GLP-1A19T (K6UbGLP-1A19T) is expressed as form of inclusion body with little formation of the soluble aggregation in recombinant E. coli. In order to produce K6UbGLP-1A19T in large amounts, fed-batch fermentation was carried out in a pH-stat feeding strategy. Maximum dry cell weight of 87.7 g/L and 20.4% of specific K6UbGLP-1A19T content were obtained. Solid-phase refolding using a cation exchanger was carried out to renature K6UbGLP-1A19T. The refolded K6UbGLP-1A19T aggregated little and was released GLP-1A19T by on-column cleavage with ubiquitin-specific protease-1. The molecular mass of GLP-1A19T showed an accurate agreement with its theoretical molecular mass.

• BMB Reports
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• 제38권3호
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• pp.334-342
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• 2005

Recently, the existence of T cells with dual T cell receptor (TCR) in the immune system is generally accepted, while it has been controversial whether signals through one TCR would affect the functions of the other. In this study T cells expressing two different TCR were obtained from cross-hybrids of LCMV and AND TCR transgenic mice specific for the gp33 and peptide fragment of PCC (fPCC), respectively. Peptide stimulation demonstrated that the dual TCR T cells functioned independently in an antigen-specific manner. To examine whether the tolerance targeted for the one TCR affects the responsiveness of the other, the cross-hybrids were treated with gp33. Although T cells from F1 mice were rendered anergenic to gp33, no functional changes to fPCC were observed in terms of cellular proliferation and IL-2 secretion, suggesting that the dual TCR T cells remained reactive to fPCC. We therefore propose that signaling through the TCR is receptor-specific and 'negative dominance' of one TCR by tolerance induction is not applicable in this dual TCR system.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3703-3706
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• 2010

Biomolecules specific to explosives can be exploited as chemical sensors. Peptides specific to immobilized dinitrotoluene (DNT) were identified using a phage display library. A derivative of DNT that contained an extended amine group, 4-(2,4-dinitrophenyl)butan-1-amine, was synthesized and immobilized using a self-assembled monolayer surface on gold. Filamentous M13 phages displaying random sequences of 12-mer peptides specific to the immobilized DNT-derivate were isolated from the M13 phage library by biopanning. A common peptide sequence was identified from the isolated phages and the synthesized peptides showed selective binding to DNT. When the peptide was immobilized on a quartz crystal microbalance (QCM) chip, it showed a binding signal to DNT, while toluene barely showed significant binding to the QCM chip. These results demonstrate that peptides screened by biopanning against immobilized DNT can be useful for quick and accurate detection of DNT.