• 한국임상수의학회지
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• 제8권1호
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• pp.1-10
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• 1991

The B-lymphocyte differentiation from committed B-cell progenitors to antibody-secreting cells was discussed. B-cell progenitors derived from hematopoietic stem cells undergo the rearrangement of immunoglobulin(Ig) gene. The earliest cells as B-cell precursors have cytoplasmic Is(${\mu}$ chain). The entire Is molecule is expressed on the surface after synthesis of L chain. The resting B cells(Go stage) stimulated by binding antigen via Ig-receptors are activated(G$_1$ stage) and followed by proliferation(S stage), coupled with further selection(affinity maturation. class switch). The production of antibody against a particular antigen depends on the activation of B cells with surface Is capable of reacting with that antigen. This process does not occur in isolation but is controlled by helper and suppressor T cells and antigen presenting cells(APC). The mechanism of T cell-dependent B-cell response for production of antibody is largely explained by the cell to cell cooperation and soluble helper factors of T cells. 1) The antigen specific B cells and helper T cells are linked by Is-receptors, leading to the delivery of helper signals to the B cells. 2) Helper T cells recognize the processed antigen-derived peptides with the MHC class II molecules(la antigen) and is stimulated to secrete B-cell proliferation and differentiation factors which activate B cells of different antigenic specificity. The two models are shown currently 1) At low antigen concentration, only the antigen-specific B cell binds antigen and presents antigen-derived peptides with la molecules to helper T cells, which are stimulated to secrete cytokines(IL-4, IL-5, etc.) and 2) At high antigen concentration, antigen-derived peptides are presented by specific B cells, by B cells that endocytose the antigens, as well as by APC Cytokines secreted from helper T cells also lead to the activation of B cells and even bystander B cells in the on- vironmment and differentiate them into antibody-secreting plasma cells.

• Biomolecules & Therapeutics
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• 제27권1호
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• pp.78-84
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• 2019

Cell therapeutic agents for treating degenerative brain diseases using neural stem cells are actively being developed. However, few systems have been developed to monitor in real time whether the transplanted neural stem cells are actually differentiated into neurons. Therefore, it is necessary to develop a technology capable of specifically monitoring neuronal differentiation in vivo. In this study, we established a system that expresses cell membrane-targeting red fluorescent protein under control of the Synapsin promoter in order to specifically monitor differentiation from neural stem cells into neurons. In order to overcome the weak expression level of the tissue-specific promoter system, the partial 5' UTR sequence of Creb was added for efficient expression of the cell surface-specific antigen. This system was able to track functional neuronal differentiation of neural stem cells transplanted in vivo, which will help improve stem cell therapies.

• IMMUNE NETWORK
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• 제1권1호
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• pp.1-6
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• 2001

The identification of tumor-specific antigens has represented a critical milestone in cancer diagnosis and therapy. Clinical research in this area for leukemia has also been driven over the past few decades by the hope that surface antigens with restricted tissue expression would be identified. Disappointingly, only a small number of the leukemic antigens identified to date, meet sufficient criteria to be considered viable immunophenotypic markers. In this paper, we nominate anti-JL1 monoclonal antibody as an immunodiagnostic and immunotherapeutic candidate for leukemia. The JL1 molecule appears to be a novel cell surface antigen, which is strictly confined to a subpopulation of limited stages during the hematopoietic differentiation process. Despite the restricted distribution of the JL1 antigen in normal tissues and cells, anti-JL1 monoclonal antibody specifically recognizes various types of leukemia, irrespective of immunophenotypes. On the basis of these findings, we propose JL1 antigen as a tumor-specific marker, which shows promise as a candidate molecule for diagnosis and immunotherapy in leukemia, and one that spares normal bone marrow stem cells.

• 대한수의학회지
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• 제36권2호
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• pp.337-348
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• 1996

The proportion of leukocyte subpopulation in the host is of a great importance in understanding their functions and disease progress. Many methods have been developed to seperate leukocytes and to measure their activities. Characterization of immune cell subpopulations in Korean native cattle was performed using a set of monoclonal antibodies specific which are specific to bovine leukocyte differentiation antigen. Peripheral blood leukocytes from fifty Korean native and ten Holstein cattle were collected and analyzed for the investigation of leukocyte subpopulation by using monoclonal antibodies and flow cytometry. The result indicated that Korean native cattle have significantly higher proportion of leukocyte subpopulations expressing MHC class II molecules and BoCD4 than Holstein cattle.

• IMMUNE NETWORK
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• 제14권6호
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• pp.328-332
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• 2014

Dexamethasone (Dex) was shown to inhibit the differentiation, maturation, and antigen-presenting function of dendritic cells (DC) when added during DC generation or maturation stages. Here, we examined the direct effects of Dex on MHC-restricted antigen processing. Macrophages were incubated with microencapsulated ovalbumin (OVA) in the presence of different concentrations of Dex for 2 h, and the efficacy of OVA peptide presentation was evaluated using OVA-specific CD8 and CD4 T cells. Dex inhibited both class I- and class II-restricted presentation of OVA to T cells; this inhibitory effect on antigen presentation was much more potent in immature macrophages than in mature macrophages. The presentation of the exogenously added OVA peptide SIINFEKL was not blocked by Dex. In addition, short-term treatment of macrophages with Dex had no discernible effects on the phagocytic activity, total expression levels of MHC molecules or co-stimulatory molecules. These results demonstrate that Dex inhibits intracellular processing events of phagocytosed antigens in macrophages.

• 한국동물학회지
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• 제39권1호
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• pp.12-20
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• 1996

K562 적혈구암 세포는 phorbol 12-myristate 13-acetate(PMA)에 의해서 대핵세포로 분화되고 gpIlla의 증가, megakaryocyte와 유사한 형태학적 변화로 특징지워진다. 또한 K562 세포는 dimethy1 sulfoxide(DMSO)나 butyrate와 같은 화학적 유도원에 의해 적혈구로 분화가 유도되고 동시에 헤모글로빈이 축척된다. 본 연구에서는 K562 세포에 대한 단일클론 항체를 생성하고 이를 이용하고 61 KDa의 표면항원을 동정하였다. 단클론항체 EK-2에 의해 인지되는 61 KDa의 표면항원은 sialic acide가 풍부해 당단백질로 사료되고, 그 epitope는 neuraminidase 절단과 peroxidase oxidation에 민감하며, 열처리에는 안정하다. K562 세포의 대핵세포로 분화시에는 61 KDa 표면항원의 발현은 증가하며, 적혈구로 분회시에는 그 발현이 감소한다. EK-2 단클론항체는 조혈세포의 분화 및 암화과정의 분자적 수준을 연구하기 위한 면역학적 probe로 이용 가능할 것으로 기대된다.

• Biomolecules & Therapeutics
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• 제15권4호
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• pp.218-223
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• 2007

T cell proliferation is a pivotal to an effective immune response. Cyclin-dependent kinase (cdk) inhibitor, $p27^{kip1}$ is degraded to initiate T cell expansion. In this study, we show that although the expression of $p27^{kip1}$ protein was down-regulated, that of $p21^{cip1}$, another cdk inhibitor, was up-regulated in $CD8^+$ T cells following in vitro stimulation. Ex vivo gB antigen-stimulation following HSV immunization increased $p21^{cip1}$ positive cells that co-expressed IFN-$\gamma$. Moreover, $p21^{cip1}$ was co-expressed with IFN-${\gamma}$ in E7 antigen-stimulated $CD8^+$ T cells, whereas $p27^{kip1}$ was not. Our findings imply a role of $p21^{cip1}$ proteins in antigen-induced effector $CD8^+$ T cells differentiation in vivo.

• 한국미생물·생명공학회지
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• 제23권1호
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• pp.110-117
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• 1995

This study was carried out to immunologically characterize Bacillus thuringiensis (B.t) antigens. Protein patterns of ultrasonicated- antigens of B. thuringiensis subspecies using SDS- PAGE revealed marked similarities among all the strains analyzed except for the difference between quantative variations of bands and some protein antigens. The comparison of the protein patterns showed that the protein antigen of 45 kilodalton (kd) was common in 11 strains and that the difference between B. thuringiensis subsp. canadensis and galleriae was noticed in quantative variations of bands despite of ambiguous serogrouping, suggesting a useful method for identification. All strains examined showed similar antigenic patterns in SDS-PAGE, while immunodominant bands differed in antigenic reactivity in western blot using polyclonal antibodies. Polyclonal antibody to B. thuringiensis subsp. thuringiensis and israelensis in indirect immunofluorescence assay reacted with flagella and cell surface antigens. The present study indicates that SDS-PAGE and western blot analysis may be used as tools for differentiation and identification of B. thuringiensis subspecies.

• Journal of Periodontal and Implant Science
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• 제44권5호
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• pp.235-241
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• 2014

Purpose: Regulatory T cells (Tregs), expressing CD4 and CD25 as well as Foxp3, are known to play a pivotal role in immunoregulatory function in autoimmune diseases, cancers, and graft rejection. Dendritic cells (DCs) are considered the major antigen-presenting cells (APCs) for initiating these T-cell immune responses, of which $CD103^+$ DCs are derived from precursor human peripheral blood mononuclear cells (PBMCs). The aim of the present study was to evaluate the capacity of these PBMC-derived $CD103^+$ DCs to promote the differentiation of antigen-specific Tregs. Methods: Monocyte-derived DCs were induced from $CD14^+$ monocytes from the PBMCs of 10 healthy subjects. Once the $CD103^+$ DCs were purified, the cell population was enriched by adding retinoic acid (RA). Peptide numbers 14 and 19 of Porphyromonas gingivalis heat shock protein 60 (HSP60) were synthesized to pulse $CD103^+$ DCs as a tool for presenting the peptide antigens to stimulate $CD3^+$ T cells that were isolated from human PBMC. Exogenous interleukin 2 was added as a coculture supplement. The antigen-specific T-cell lines established were phenotypically identified for their expression of CD4, CD25, or Foxp3. Results: When PBMCs were used as APCs, they demonstrated only a marginal capacity to stimulate peptide-specific Tregs, whereas $CD103^+$ DCs showed a potent antigen presenting capability to promote the peptide-specific Tregs, especially for peptide 14. RA enhanced the conversion of $CD103^+$ DCs, which paralleled the antigen-specific Treg-stimulating effect, though the differences failed to reach statistical significance. Conclusions: We demonstrated that $CD103^+$ DCs can promote antigen-specific Tregs from naive T cells, when used as APCs for an epitope peptide from P. gingivalis HSP60. RA was an effective reagent that induces mature DCs with the typical phenotypic expression of CD103 that demonstrated the functional capability to promote antigen-specific Tregs.

• Asian-Australasian Journal of Animal Sciences
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• 제33권3호
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• pp.515-524
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• 2020

Objective: Human mesenchymal stromal cells (MSCs) exhibit variable differentiation potential and can be divided accordingly into distinct subpopulations whose ratios vary with donor age. However, it is unknown whether the same is true in pigs. This study investigated MSC subpopulations in miniature pig and compared their characteristics in young (2 to 3 months) and adult (27 to 35 months) pigs. Methods: Osteogenic, chondrogenic, and adipogenic capacity of isolated MSCs was evaluated by von Kossa, Alcian blue, and oil red O staining, respectively. Cell surface antigen expression was determined by flow cytometry. Proliferative capacity was assessed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Expression of marker genes was detected by quantitative real-time polymerase chain reaction. Results: Porcine MSCs comprised cells with trilineage and bilineage differentiation potential (tMSCs and bMSCs, respectively) and non-differentiating stromal cells (NDSCs). The tMSC and bMSC fractions were smaller in adult than in young pigs (63.0% vs 71.2% and 11.6% vs 24.0%, respectively, p<0.05); NDSCs showed the opposite trend (25.4% vs 4.8%; p<0.05). Subpopulations showed no differences in morphology, cell surface antigen expression, or proliferative capacity, but octamer-binding transcription factor 4 (OCT4) expression was higher in tMSCs than in bMSCs and NDSCs (p<0.05), whereas sex determining region Y-box 2 (SOX2) expression was higher in tMSCs and bMSCs than in NDSCs (p<0.05). Aging had no effect on these trends. Conclusion: Porcine MSCs comprise distinct subpopulations that differ in their differentiation potential and OCT4 and SOX2 expression. Aging does not affect the characteristics of each subpopulation but alters their ratios.