• IMMUNE NETWORK
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• 제6권2호
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• pp.102-110
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• 2006

Background: Dendritic cells (DC) are professional antigen-presenting cells in the immune system and can induce T cell response against virus infections, microbial pathogens, and tumors. Therefore, immunization using DC loaded with tumor-associated antigens (TAAs) is a powerful method of inducing anti-tumor immunity. For induction of effective anti-tumor immunity, antigens should be efficiently introduced into DC and presented on MHC class I molecules at high levels to activate antigen-specific $CD8^+$ T cells. We have been exploring methods for loading exogenous antigens into APC with high efficiency of Ag presentation. In this study, we tested the effect of the cationic liposome (Lipofectin) for transferring and loading exogenous model antigen (OVA protein) into BM-DC. Methods: Bone marrow-derived DC (EM-DC) were incubated with OVA-Lipofectin complexes and then co-cultured with B3Z cells. B3Z activation, which is expressed as the amount of ${\beta}$-galactosidase induced by TCR stimulation, was determined by an enzymatic assay using ${\beta}$-gal assay system. C57BL/6 mice were immunized with OVA-pulsed DC to monitor the in vivo vaccination effect. After vaccination, mice were inoculated with EG7-OVA tumor cells. Results: BM-DC pulsed with OVA-Lipofectin complexes showed more efficient presentation of OVA-peptide on MHC class I molecules than soluble OVA-pulsed DC. OVA-Lipofectin complexes-pulsed DC pretreated with an inhibitor of MHC class I-mediated antigen presentation, brefeldin A, showed reduced ability in presenting OVA peptide on their surface MHC class I molecules. Finally, immunization of OVA-Lipofectin complexes-pulsed DC protected mice against subsequent tumor challenge. Conclusion: Our data provide evidence that antigen-loading into DC using Lipofectin can promote MHC class I- restricted antigen presentation. Therefore, antigen-loading into DC using Lipofectin can be one of several useful tools for achieving efficient induction of antigen-specific immunity in DC-based immunotherapy.

• Asian Pacific Journal of Cancer Prevention
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• 제16권2호
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• pp.571-578
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• 2015

Prostate cancer is the most common cancer in men. In this study, we investigated immune responses of cytotoxic T lymphocytes (CTLs) against TRAMP-C2 prostate cancer cells after activation by dendritic cells (DCs) loaded with TRAMP-C2 freeze-thaw antigen and/or PEP-3 peptide in vitro. Bone marrow-derived DC from the bone marrow of the C57BL/6 were induced to mature by using the cytokine of rhGM-CSF and rhIL-4, and loaded with either the freeze-thaw antigen or PEP-3 peptide or both of them. Maturation of DCs was detected by flow cytometry. The killing efficiency of the CTLs on TRAMP-C2 cells were detected by flow cytometry, CCK8, colony formation, transwell migration, and wound-healing assay. The levels of the IFN-${\gamma}$, TNF-${\beta}$ and IL-12 were measured by enzyme-linked immunosorbent assay (ELISA). Compared with the unloaded DCs, the loaded DCs had significantly increased expression of several phenotypes related to DC maturation. CTLs activated by DCs loaded with freeze-thaw antigen and PEP-3 peptide had more evident cytotoxicity against TRAMP-C2 cells in vitro. The secretion levels of IFN-${\gamma}$, TNF-${\beta}$ and IL-12, secreted by DCs loaded with antigen and PEP-3 and interaction with T cells, were higher than in the other groups. Our results suggest that the CTLs activated by DCs loaded with TRAMP-C2 freeze-thaw antigen and PEP-3 peptide exert a remarkable killing efficiency against TRAMP-C2 cells in vitro.

• KSBB Journal
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• 제19권6호
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• pp.415-420
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• 2004

전 세계적으로 암의 발병률의 증가하고 있고 또한 그 수는 해마다 증가하는 실정이다. 암은 성장양상에 따라 악성종양과 양성종양으로 나뉘는데 암으로 구분되는 악성종양을 치료하기 위한 여러 가지 치료법들이 시행되고 또 개발되고 있다. 그중에서 dendritic cells (DCs)는 인체 내 면역반응을 이용하여 암을 치료하는 방법으로 적응면역에 관여하는 cytotoxic T cell (CTL)에 항원을 제시하여 CTL로 하여금 종양세포를 직접적으로 공격하도록 도움을 주는 역할을 한다. 그러나 여기에는 여러 가지 단점이 있다. 이 단점을 보완하기 위한 새로운 방법으로 artificial antigen-presenting cell (aAPC)을 이용한 치료법이 개발되고 있다. 가용성의 human leukocyte antigen-immunoglobulin fusion protein (HLA-Ig)를 기초한 aAPC은 DCs의 단점을 보완한 항원제시세포로써 DCs보다 더욱 효과적으로 CTL반응을 유도해 낼 것으로 기대한다. 본 총설에서는 이 DCs의 역할과 이들을 이용한 암 치료법에 대해서 논하고 그 개발 가능성에 대해서 알아보도록 하겠다.

• 미생물학회지
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• 제47권4호
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• pp.342-347
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• 2011

인체의 바이러스 감염 방어기전에서 T 림프구는 중요한 역할을 한다. 하지만, 만성 C형 간염 바이러스의 일차적 복제장소인 간염 환자의 간에서 분리된 HCV 특이 T 림프구는 심각한 기능결핍을 보인다. 이러한 T 림프구 기능결핍의 이유로는 PD-1, CTLA-4 등 면역억제 물질의 발현, 또는 간에서 특이적으로 유도되는 면역내성(immune tolerance)이 있으나, 간세포(hepatocytes)와 HCV 특이 T 림프구의 상호작용에 대해서는 명확하게 확립되어 있지 않다. 따라서 본 연구에서는 HLA(human leukocyte antigen) A2+ 간암세포주(human hepatoma cell line; huh7.5)가 항원제시(antigen presentation)를 통해 효과적으로 HCV 특이 T 림프구를 활성화시키며 간암세포주(huh7.5) 표면의 PD-L (program death ligand) 1 발현은 T림프구의 활성을 감소시켜 면역조절의 가능성이 있음을 시사하였다. 또한, HCV 특이 tetramer 반응은 T 림프구의 과도한 활성으로 자기사멸(apoptosis)의 경로에 있음을 caspase 3 활성으로 확인하였고, 역시 PD-L1의 발현이 T 림프구를 자기사멸(apoptosis)로부터 구제하여 caspase 3 활성이 감소하는 것을 확인하였다. 이는 PD-L1과 간성(liver) T 림프구 표면의 PD-1 결합이 T 림프구의 자기사멸을 막고, 또한 그 기능을 회복시켜 만성 C형 간염 치료에 응용될 수 있음을 시사한다.

• The Korean Journal of Physiology and Pharmacology
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• 제27권3호
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• pp.241-256
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• 2023

Although chimeric antigen receptor T cell (CAR-T) is a promising immunotherapy in hematological malignancies, there remain many obstacles to CART cell therapy for solid tumors. Identifying appropriate tumor-associated antigens (TAAs) is especially critical for success. Using a bioinformatics approach, we identified common potential TAAs for CAR-T cell immunotherapy in solid tumors. We used the GEO database as a training dataset to find differentially expressed genes (DEGs) and verified candidates using the TCGA database, obtaining seven common DEGs (HM13, SDC1, MST1R, HMMR, MIF, CD24, and PDIA4). Then, we used MERAV to analyze the expression of six genes in normal tissues to determine the ideal target genes. Finally, we analyzed tumor microenvironment factors. The results of major microenvironment factor analyses showed that MDSCs, CXCL1, CXCL12, CXCL5, CCL2, CCL5, TGF- β, CTLA-4, and IFN-γ were significantly overexpressed in breast cancer. The expression of MST1R was positively correlated with TGF- β, CTLA-4, and IFN-γ. In lung adenocarcinoma, MDSCs, Tregs, CXCL12, CXCL5, CCL2, PD-L1, CTLA-4, and IFN-γ were significantly overexpressed in tumor tissues. The expression of MST1R was positively correlated with TGF- β, CTLA-4, and IFN-γ. In bladder cancer, CXCL12, CCL2, and CXCL5 were significantly overexpressed in tumor tissues. MST1R expression was positively correlated with TGF- β. Our results demonstrate that MST1R has the potential as a new target antigen for treating breast cancer, lung adenocarcinoma, and bladder cancer and may be used as a progression indicator for bladder cancer.

• IMMUNE NETWORK
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• 제3권3호
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• pp.169-175
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• 2003

The intestinal immune system can discriminate between harmful and unharmful antigens and do not provoke productive immunity to unharmful antigen. Thus oral administration of antigen is one of classical methods for inducing antigen-specific immune tolerance in the periphery. Furthermore, oral tolerance has been investigated for the treatment of autoimmune disorders in human clinical trials. However, the detail mechanism of oral tolerance and contributing factors are not defined clearly at this time. Recent studies demonstrate unique types of immune cell that suppressing immune response, such as regulatory T cell and tolerogenic dendritic cell. This article reviews the factors involved in oral tolerance and discusses our current understanding base on the recent literatures and our works.

• 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.

• 한국동물학회지
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• 제17권2호
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• pp.51-56
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• 1974

生後 24시간 이내의 어린 Armenian hamster와 Chinese hamster의 體內에 adenovirus type 12를 注入할 경우, 전자에서는 27일, 후자에서는 30$\\sim$45일이 지난후 腫瘍모양을 한 작은 細胞傀가 생김을 보았다. 이들 細胞傀는 다른 個體에 移植이 가능하며, 上皮細胞와 같은 모양을 하고 있다. 本實驗에서 얻어진 57개의 細胞傀 중에서 6개만이 細胞培養 되었으며 14$\\sim$20회 정도 繼代培養을 계속하는 동안에 染色體의 변동은 없이 細胞의 모양이 纖維狀으로 변하였다. 이들 細胞가 上皮細胞 모양을 할 때는 腫瘍性이며, T-抗體도 발견되었는데, 纖維狀으로 변하게 되면 腫瘍性을 나타내지 않으며, T-抗體도 찾아 볼 수 없다. 다른 2개의 細胞傀를 上皮細胞 모양일 때 SV40 바이러스로 처리하면 바로 纖維狀細胞로 변한다. 이들 細胞에는 adenovirus에 의한 T-抗體는 없으나, SV40의 T-抗體가 존재하며, 다른 hamster에 移植할 경우 皮腫 모양의 細胞傀를 이룬다.

• 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.

• IMMUNE NETWORK
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• 제7권4호
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• pp.197-202
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• 2007

Background: Immunomodulators enhancing MHC-restricted antigen presentation would affect many cellular immune reactions mediated by T cells or T cell products. However, modulation of MHC-restricted antigen presentation has received little attention as a target for therapeutic immunoregulation. Here, we report that lectins isolated from mushroom Fomitella fraxinea enhance MHC-restricted exogenous antigen presentation in professional antigen presenting cells (APCs). Methods: Lectins, termed FFrL, were isolated from the carpophores of Fomitella fraxinea, and its effects on the class I and class II MHC-restricted presentation of exogenous ovalbumin (OVA) were examined in mouse dendritic cells (DCs) and mouse peritoneal macrophages. The effects of FFrL on the expression of total MHC molecules and the phagocytic activity were also examined in mouse DCs. Results: DCs cultured in the presence of FFrL overnight exhibited enhanced capacity in presenting exogenous OVA in association with class I and class II MHC molecules. FFrL increased slightly the total expression levels of both class I (H-$2K^b$) and class II (I-$A^b$) MHC molecules and the phagocytic activity of DCs. Antigen presentation-enhancing activity of FFrL was also observed in macrophages isolated from mouse peritoneum. Conclusion: Lectins isolated from the carpophores of Fomitella fraxinea increase MHC-restricted exogenous antigen presentation by enhancing intracellular processing events of phagocytosed antigens.