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Shi W, Qiu Q, Feng Z, Tong Z, Guo W, Zou F, Yue N, Huang W, Qian H. Design, synthesis and immunological evaluation of self-assembled antigenic peptides from dual-antigen targets: a broad-spectrum candidate for an effective antibreast cancer therapy. J Immunother Cancer 2021; 9:jitc-2021-002523. [PMID: 34083420 PMCID: PMC8183215 DOI: 10.1136/jitc-2021-002523] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2021] [Indexed: 12/11/2022] Open
Abstract
Background Considering the narrow immune response spectrum of a single epitope, and the nanoparticles (NPs) as a novel adjuvant can achieve efficient delivery of antigenic peptides safely, a nano-system (denoted as DSPE-PEG-Man@EM-NPs) based on cathepsin B-responsive antigenic peptides was designed and synthesized. Methods Highly affinitive antigenic peptides were delivered by self-assembled NPs, and targeted erythrocyte membranes acted as a peptide carrier to improve antigenic peptides presentation and to strengthen cytotoxic T-cells reaction. Cathepsin B coupling could release antigenic peptides rapidly in dendritic cells. Results Evaluations showed that DSPE-PEG-Man@EM-NPs had obvious inhibitory effects towards both MCF-7 and MDA-MB-231 human breast cancer cell lines. Conclusion Overall, this strategy provides a novel strategy for boosting cytotoxic T lymphocytes response, thereby expanding the adaptation range of tumor antigenic peptides and improving the therapeutic effect of tumor immunotherapy with nanomedicine.
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Affiliation(s)
- Wei Shi
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Qianqian Qiu
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China.,School of Pharmacy, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, Yancheng Teachers' University, Yancheng 224002, China
| | - Ziying Feng
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Zhenzhen Tong
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Weiwei Guo
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Feng Zou
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Na Yue
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Wenlong Huang
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China.,Jiangsu Key Laboratory of Drug Discovery for Metabolic Disease, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, Jiangsu, China
| | - Hai Qian
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China .,Jiangsu Key Laboratory of Drug Discovery for Metabolic Disease, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, Jiangsu, China
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2
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Karle AC. Applying MAPPs Assays to Assess Drug Immunogenicity. Front Immunol 2020; 11:698. [PMID: 32373128 PMCID: PMC7186346 DOI: 10.3389/fimmu.2020.00698] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/27/2020] [Indexed: 01/08/2023] Open
Abstract
Immunogenicity against biotherapeutic proteins (BPs) and the potential outcome for the patient are difficult to predict. In vitro assays that can help to assess the immunogenic potential of BPs are not yet used routinely during drug development. MAPPs (MHC-associated peptide proteomics) is one of the assays best characterized regarding its value for immunogenicity potential assessment. This review is focusing on recent studies that have employed human HLA class II-MAPPs assays to rank biotherapeutic candidates, investigate clinical immunogenicity, and understand mechanistic root causes of immunogenicity. Advantages and challenges of the technology are discussed as well as the different areas of application.
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Affiliation(s)
- Anette C Karle
- Novartis Institute for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
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3
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Wang CY, Deneen B, Tzeng SF. BRCA1/BRCA2-containing complex subunit 3 controls oligodendrocyte differentiation by dynamically regulating lysine 63-linked ubiquitination. Glia 2019; 67:1775-1792. [PMID: 31184779 DOI: 10.1002/glia.23660] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 01/19/2023]
Abstract
Oligodendrocytes (OLs) provide the myelin sheath surrounding axons that propagates action potentials in the central nervous system (CNS). The metabolism of myelinated membranes and proteins is strictly regulated in the OLs and is closely associated with OL differentiation and maturation. The ubiquitination-associated proteasome and endosomal system have not yet been well studied during OL differentiation and maturation. Here, we determined the functions of the Lys63-linked ubiquitination (K63Ub) and K63-specific deubiquitination (DUB) systems regulated by BRCA1/BRCA2-containing complex subunit 3 (BRCC3) during OL differentiation. The competitive inhibition of K63Ub by overexpression of mutant ubiquitin (K63R) in oligodendrocyte precursor cells (OPCs) indicated that the two major CNS myelin proteins, myelin basic protein (MBP) and proteolipid protein (PLP), were upregulated in OLs derived from K63R OPCs. In contrast, the knockdown of BRCC3 (BRCC3-KD) through the application of lentivirus-mediated shRNA delivery system into OPCs suppressed OL differentiation by decreasing MBP expression and PLP production. Further immunoprecipitation assays revealed higher levels of sphingolipid GalC, MBP, and PLP, which were associated with K63Ub-immunoprecipitants and detected in endosome/lysosomal compartments, in BRCC3-KD OLs than those in OLs transfected with the scrambled shRNA (scramble OLs). The differentiation of OLs from BRCC3-KD OPCs was impaired in the demyelinating corpus callosum of rats receiving a cuprizone-containing diet. In the demyelinating tissues from human patients suffering from multiple sclerosis, we detected a decreased number of BRCC3-expressing OLs at the lesion site, accompanied by a greater number of OLs expressing EEA1 and K63Ub at high levels. Altogether, the counterbalance of the K63Ub machinery and BRCC3-triggered DUB machinery are important for the cellular trafficking of myelin proteins and OL differentiation.
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Affiliation(s)
- Chih-Yen Wang
- Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Benjamin Deneen
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas
| | - Shun-Fen Tzeng
- Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
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4
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Class II MHC antigen processing in immune tolerance and inflammation. Immunogenetics 2018; 71:171-187. [PMID: 30421030 DOI: 10.1007/s00251-018-1095-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/31/2018] [Indexed: 01/22/2023]
Abstract
Presentation of peptide antigens by MHC-II proteins is prerequisite to effective CD4 T cell tolerance to self and to recognition of foreign antigens. Antigen uptake and processing pathways as well as expression of the peptide exchange factors HLA-DM and HLA-DO differ among the various professional and non-professional antigen-presenting cells and are modulated by cell developmental state and activation. Recent studies have highlighted the importance of these cell-specific factors in controlling the source and breadth of peptides presented by MHC-II under different conditions. During inflammation, increased presentation of selected self-peptides has implications for maintenance of peripheral tolerance and autoimmunity.
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5
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Woo SM, Min KJ, Seo SU, Kim S, Park JW, Song DK, Lee HS, Kim SH, Kwon TK. Up-regulation of 5-lipoxygenase by inhibition of cathepsin G enhances TRAIL-induced apoptosis through down-regulation of survivin. Oncotarget 2017; 8:106672-106684. [PMID: 29290980 PMCID: PMC5739765 DOI: 10.18632/oncotarget.22508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/01/2017] [Indexed: 01/04/2023] Open
Abstract
Cathepsin G is a serine protease secreted from activated neutrophils, it has important roles in inflammation and immune response. Moreover, cathepsin G promotes tumor cell-cell adhesion and migration in cancer cells. In this study, we investigated whether inhibition of cathepsin G could sensitize TRAIL-mediated apoptosis in cancer cells. An inhibitor of cathepsin G [Cathepsin G inhibitor I (Cat GI); CAS 429676-93-7] markedly induced TRAIL-mediated apoptosis in human renal carcinoma (Caki, ACHN, and A498), lung cancer (A549) and cervical cancer (Hela) cells. In contrast, combined treatment with Cat GI and TRAIL had no effect on apoptosis in normal cells [mesangial cell (MC) and human skin fibroblast (HSF)]. Cat GI induced down-regulation of survivin expression at the post-translational level, and overexpression of survivin markedly blocked apoptosis induced by combined treatment with Cat GI plus TRAIL. Interestingly, Cat GI induced down-regulation of survivin via 5-lipoxygenase (5-LOX)-mediated reactive oxygen species (ROS) production. Inhibition of 5-LOX by gene silencing (siRNA) or a pharmacological inhibitor of 5-LOX (zileuton) markedly attenuated combined treatment-induced apoptosis. Taken together, our results indicate that inhibition of cathepsin G sensitizes TRAIL-induced apoptosis through 5-LOX-mediated down-regulation of survivin expression.
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Affiliation(s)
- Seon Min Woo
- Department of Immunology, School of Medicine, Keimyung University, Dalseo-Gu, Daegu 704-701, South Korea
| | - Kyoung-Jin Min
- Department of Immunology, School of Medicine, Keimyung University, Dalseo-Gu, Daegu 704-701, South Korea
| | - Seung Un Seo
- Department of Immunology, School of Medicine, Keimyung University, Dalseo-Gu, Daegu 704-701, South Korea
| | - Shin Kim
- Department of Immunology, School of Medicine, Keimyung University, Dalseo-Gu, Daegu 704-701, South Korea
| | - Jong-Wook Park
- Department of Immunology, School of Medicine, Keimyung University, Dalseo-Gu, Daegu 704-701, South Korea
| | - Dae Kyu Song
- Department of Physiology, School of Medicine, Keimyung University, Dalseo-Gu, Daegu 704-701, South Korea
| | - Hyun-Shik Lee
- KNU-Center for Nonlinear Dynamics, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, Daegu 41566, South Korea
| | - Sang Hyun Kim
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Taeg Kyu Kwon
- Department of Immunology, School of Medicine, Keimyung University, Dalseo-Gu, Daegu 704-701, South Korea
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6
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Bischof J, Westhoff MA, Wagner JE, Halatsch ME, Trentmann S, Knippschild U, Wirtz CR, Burster T. Cancer stem cells: The potential role of autophagy, proteolysis, and cathepsins in glioblastoma stem cells. Tumour Biol 2017; 39:1010428317692227. [PMID: 28347245 DOI: 10.1177/1010428317692227] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
One major obstacle in cancer therapy is chemoresistance leading to tumor recurrence and metastasis. Cancer stem cells, in particular glioblastoma stem cells, are highly resistant to chemotherapy, radiation, and immune recognition. In case of immune recognition, several survival mechanisms including, regulation of autophagy, proteases, and cell surface major histocompatibility complex class I molecules, are found in glioblastoma stem cells. In different pathways, cathepsins play a crucial role in processing functional proteins that are necessary for several processes and proper cell function. Consequently, strategies targeting these pathways in glioblastoma stem cells are promising approaches to interfere with tumor cell survival and will be discussed in this review.
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Affiliation(s)
- Joachim Bischof
- 1 Department of General and Visceral Surgery, Surgery Center, Ulm University Medical Center, Ulm University, Ulm, Germany
| | - Mike-Andrew Westhoff
- 2 Department Pediatrics and Adolescent Medicine, Ulm University Medical Center, Ulm University, Ulm, Germany
| | - Johanna Elisabeth Wagner
- 3 Department of Neurosurgery, Surgery Center, Ulm University Medical Center, Ulm University, Ulm, Germany
| | - Marc-Eric Halatsch
- 3 Department of Neurosurgery, Surgery Center, Ulm University Medical Center, Ulm University, Ulm, Germany
| | - Stephanie Trentmann
- 1 Department of General and Visceral Surgery, Surgery Center, Ulm University Medical Center, Ulm University, Ulm, Germany
| | - Uwe Knippschild
- 1 Department of General and Visceral Surgery, Surgery Center, Ulm University Medical Center, Ulm University, Ulm, Germany
| | - Christian Rainer Wirtz
- 3 Department of Neurosurgery, Surgery Center, Ulm University Medical Center, Ulm University, Ulm, Germany
| | - Timo Burster
- 3 Department of Neurosurgery, Surgery Center, Ulm University Medical Center, Ulm University, Ulm, Germany
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7
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Riedhammer C, Weissert R. Antigen Presentation, Autoantigens, and Immune Regulation in Multiple Sclerosis and Other Autoimmune Diseases. Front Immunol 2015; 6:322. [PMID: 26136751 PMCID: PMC4470263 DOI: 10.3389/fimmu.2015.00322] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/03/2015] [Indexed: 12/12/2022] Open
Abstract
Antigen presentation is in the center of the immune system, both in host defense against pathogens, but also when the system is unbalanced and autoimmune diseases like multiple sclerosis (MS) develop. It is not just by chance that a major histocompatibility complex gene is the major genetic susceptibility locus in MS; a feature that MS shares with other autoimmune diseases. The exact etiology of the disease, however, has not been fully understood yet. T cells are regarded as the major players in the disease, but most probably a complex interplay of altered central and peripheral tolerance mechanisms, T-cell and B-cell functions, characteristics of putative autoantigens, and a possible interference of environmental factors like microorganisms are at work. In this review, new data on all these different aspects of antigen presentation and their role in MS will be discussed, probable autoantigens will be summarized, and comparisons to other autoimmune diseases will be drawn.
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Affiliation(s)
- Christine Riedhammer
- Neuroimmunology, Department of Neurology, University of Regensburg , Regensburg , Germany
| | - Robert Weissert
- Neuroimmunology, Department of Neurology, University of Regensburg , Regensburg , Germany
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8
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Dinter J, Duong E, Lai NY, Berberich MJ, Kourjian G, Bracho-Sanchez E, Chu D, Su H, Zhang SC, Le Gall S. Variable processing and cross-presentation of HIV by dendritic cells and macrophages shapes CTL immunodominance and immune escape. PLoS Pathog 2015; 11:e1004725. [PMID: 25781895 PMCID: PMC4364612 DOI: 10.1371/journal.ppat.1004725] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 02/03/2015] [Indexed: 12/20/2022] Open
Abstract
Dendritic cells (DCs) and macrophages (Møs) internalize and process exogenous HIV-derived antigens for cross-presentation by MHC-I to cytotoxic CD8+ T cells (CTL). However, how degradation patterns of HIV antigens in the cross-presentation pathways affect immunodominance and immune escape is poorly defined. Here, we studied the processing and cross-presentation of dominant and subdominant HIV-1 Gag-derived epitopes and HLA-restricted mutants by monocyte-derived DCs and Møs. The cross-presentation of HIV proteins by both DCs and Møs led to higher CTL responses specific for immunodominant epitopes. The low CTL responses to subdominant epitopes were increased by pretreatment of target cells with peptidase inhibitors, suggestive of higher intracellular degradation of the corresponding peptides. Using DC and Mø cell extracts as a source of cytosolic, endosomal or lysosomal proteases to degrade long HIV peptides, we identified by mass spectrometry cell-specific and compartment-specific degradation patterns, which favored the production of peptides containing immunodominant epitopes in all compartments. The intracellular stability of optimal HIV-1 epitopes prior to loading onto MHC was highly variable and sequence-dependent in all compartments, and followed CTL hierarchy with immunodominant epitopes presenting higher stability rates. Common HLA-associated mutations in a dominant epitope appearing during acute HIV infection modified the degradation patterns of long HIV peptides, reduced intracellular stability and epitope production in cross-presentation-competent cell compartments, showing that impaired epitope production in the cross-presentation pathway contributes to immune escape. These findings highlight the contribution of degradation patterns in the cross-presentation pathway to HIV immunodominance and provide the first demonstration of immune escape affecting epitope cross-presentation. Pathogens such as HIV can enter cells by fusion at the plasma membrane for delivery in the cytosol, or by internalization in endolysosomal vesicles. Pathogens can be degraded in these various compartments into peptides (epitopes) displayed at the cell surface by MHC-I. The presentation of pathogen-derived peptides triggers the activation of T cell immune responses and the clearance of infected cells. How the diversity of compartments in which HIV traffics combined with the diversity of HIV sequences affects the degradation of HIV and the recognition of infected cells by immune cells is not understood. We compared the degradation of HIV proteins in subcellular compartments of dendritic cells and macrophages, two cell types targeted by HIV and the subsequent presentation of epitopes to T cells. We show variable degradation patterns of HIV according to compartments, and the preferential production and superior intracellular stability of immunodominant epitopes corresponding to stronger T cell responses. Frequent mutations in immunodominant epitopes during acute infection resulted in decreased production and intracellular stability of these epitopes. Together these results demonstrate the importance of protein degradation patterns in shaping immunodominant epitopes and the contribution of impaired epitope production in all cellular compartments to immune escape during HIV infection.
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Affiliation(s)
- Jens Dinter
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Ellen Duong
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Nicole Y. Lai
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Matthew J. Berberich
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Georgio Kourjian
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Edith Bracho-Sanchez
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Duong Chu
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Hang Su
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Shao Chong Zhang
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Sylvie Le Gall
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, United States of America
- * E-mail:
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9
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Zhang C, Yan K, Hu C, Zhao Y, Chen Z, Zhu X, Möller M. Encapsulation of enzymes in silica nanocapsules formed by an amphiphilic precursor polymer in water. J Mater Chem B 2015; 3:1261-1267. [DOI: 10.1039/c4tb01701c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Enzymes are encapsulated in silica nanocapsules during their formation,i.e.they are first enclosed in unilamellar vesicles formed by an amphiphilic silica precursor polymer in water, and the enzyme-loaded silica nanocapsules are then obtainedviasubsequent basic condensation.
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Affiliation(s)
- Chi Zhang
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
- China
| | - Kelu Yan
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
- China
| | - Chunyan Hu
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
- China
| | - Yongliang Zhao
- DWI – Leibniz Institute for Interactive Materials and Institute for Technical and Macromolecular Chemistry of RWTH Aachen University
- D-52056 Aachen
- Germany
| | - Zhi Chen
- DWI – Leibniz Institute for Interactive Materials and Institute for Technical and Macromolecular Chemistry of RWTH Aachen University
- D-52056 Aachen
- Germany
| | - Xiaomin Zhu
- DWI – Leibniz Institute for Interactive Materials and Institute for Technical and Macromolecular Chemistry of RWTH Aachen University
- D-52056 Aachen
- Germany
- State Key Laboratory of Molecular Engineering of Polymers
- Fudan University
| | - Martin Möller
- DWI – Leibniz Institute for Interactive Materials and Institute for Technical and Macromolecular Chemistry of RWTH Aachen University
- D-52056 Aachen
- Germany
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10
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Urra X, Miró F, Chamorro A, Planas AM. Antigen-specific immune reactions to ischemic stroke. Front Cell Neurosci 2014; 8:278. [PMID: 25309322 PMCID: PMC4162361 DOI: 10.3389/fncel.2014.00278] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 08/22/2014] [Indexed: 12/24/2022] Open
Abstract
Brain proteins are detected in the cerebrospinal fluid (CSF) and blood of stroke patients and their concentration is related to the extent of brain damage. Antibodies against brain antigens develop after stroke, suggesting a humoral immune response to the brain injury. Furthermore, induced immune tolerance is beneficial in animal models of cerebral ischemia. The presence of circulating T cells sensitized against brain antigens, and antigen presenting cells (APCs) carrying brain antigens in draining lymphoid tissue of stroke patients support the notion that stroke might induce antigen-specific immune responses. After stroke, brain proteins that are normally hidden from the periphery, inflammatory mediators, and danger signals can exit the brain through several efflux routes. They can reach the blood after leaking out of the damaged blood-brain barrier (BBB) or following the drainage of interstitial fluid to the dural venous sinus, or reach the cervical lymph nodes through the nasal lymphatics following CSF drainage along the arachnoid sheaths of nerves across the nasal submucosa. The route and mode of access of brain antigens to lymphoid tissue could influence the type of response. Central and peripheral tolerance prevents autoimmunity, but the actual mechanisms of tolerance to brain antigens released into the periphery in the presence of inflammation, danger signals, and APCs, are not fully characterized. Stroke does not systematically trigger autoimmunity, but under certain circumstances, such as pronounced systemic inflammation or infection, autoreactive T cells could escape the tolerance controls. Further investigation is needed to elucidate whether antigen-specific immune events could underlie neurological complications impairing recovery from stroke.
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Affiliation(s)
- Xabier Urra
- Functional Unit of Cerebrovascular Diseases, Hospital Clínic Barcelona, Spain ; August Pi i Sunyer Biomedical Research Institute (IDIBAPS) Barcelona, Spain
| | - Francesc Miró
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS) Barcelona, Spain
| | - Angel Chamorro
- Functional Unit of Cerebrovascular Diseases, Hospital Clínic Barcelona, Spain ; August Pi i Sunyer Biomedical Research Institute (IDIBAPS) Barcelona, Spain
| | - Anna M Planas
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS) Barcelona, Spain ; Department of Brain Ischemia and Neurodegeneration, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC) Barcelona, Spain
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11
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Mahurkar S, Suppiah V, O'Doherty C. Pharmacogenomics of interferon beta and glatiramer acetate response: A review of the literature. Autoimmun Rev 2014; 13:178-86. [DOI: 10.1016/j.autrev.2013.10.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 10/24/2013] [Indexed: 02/07/2023]
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12
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Collado JA, Guitart C, Ciudad MT, Alvarez I, Jaraquemada D. The Repertoires of Peptides Presented by MHC-II in the Thymus and in Peripheral Tissue: A Clue for Autoimmunity? Front Immunol 2013; 4:442. [PMID: 24381570 PMCID: PMC3865459 DOI: 10.3389/fimmu.2013.00442] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 11/26/2013] [Indexed: 11/13/2022] Open
Abstract
T-cell tolerance to self-antigens is established in the thymus through the recognition by developing thymocytes of self-peptide-MHC complexes and induced and maintained in the periphery. Efficient negative selection of auto-reactive T cells in the thymus is dependent on the in situ expression of both ubiquitous and tissue-restricted self-antigens and on the presentation of derived peptides. Weak or inadequate intrathymic expression of self-antigens increases the risk to generate an autoimmune-prone T-cell repertoire. Indeed, even small changes of self-antigen expression in the thymus affect negative selection and increase the predisposition to autoimmunity. Together with other mechanisms, tolerance is maintained in the peripheral lymphoid organs via the recognition by mature T cells of a similar set of self-peptides in homeostatic conditions. However, non-lymphoid peripheral tissue, where organ-specific autoimmunity takes place, often have differential functional processes that may lead to the generation of epitopes that are absent or non-presented in the thymus. These putative differences between peptides presented by MHC molecules in the thymus and in peripheral tissues might be a major key to the initiation and maintenance of autoimmune conditions.
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Affiliation(s)
- Javier A Collado
- Department of Cell Biology, Physiology and Immunology, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona , Barcelona , Spain
| | - Carolina Guitart
- Department of Cell Biology, Physiology and Immunology, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona , Barcelona , Spain
| | - M Teresa Ciudad
- Department of Cell Biology, Physiology and Immunology, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona , Barcelona , Spain
| | - Iñaki Alvarez
- Department of Cell Biology, Physiology and Immunology, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona , Barcelona , Spain
| | - Dolores Jaraquemada
- Department of Cell Biology, Physiology and Immunology, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona , Barcelona , Spain
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13
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Human cytomegalovirus infection of langerhans-type dendritic cells does not require the presence of the gH/gL/UL128-131A complex and is blocked after nuclear deposition of viral genomes in immature cells. J Virol 2013; 88:403-16. [PMID: 24155395 DOI: 10.1128/jvi.03062-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Human cytomegalovirus (CMV) enters its host via the oral and genital mucosae. Langerhans-type dendritic cells (LC) are the most abundant innate immune cells at these sites, where they constitute a first line of defense against a variety of pathogens. We previously showed that immature LC (iLC) are remarkably resistant to CMV infection, while mature LC (mLC) are more permissive, particularly when exposed to clinical-strain-like strains of CMV, which display a pentameric complex consisting of the viral glycoproteins gH, gL, UL128, UL130, and UL131A on their envelope. This complex was recently shown to be required for the infection of immature monocyte-derived dendritic cells. We thus sought to establish if the presence of this complex is also necessary for virion penetration of LC and if defects in entry might be the source of iLC resistance to CMV. Here we report that the efficiency of LC infection is reduced, but not completely abolished, in the absence of the pentameric complex. While virion penetration and nuclear deposition of viral genomes are not impaired in iLC, the transcription of the viral immediate early genes UL122 and UL123 and of the delayed early gene UL50 is substantially lower than that in mLC. Together, these data show that the UL128, UL130, and UL131A proteins are dispensable for CMV entry into LC and that progression of the viral cycle in iLC is restricted at the step of viral gene expression.
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Cohn L, Chatterjee B, Esselborn F, Smed-Sörensen A, Nakamura N, Chalouni C, Lee BC, Vandlen R, Keler T, Lauer P, Brockstedt D, Mellman I, Delamarre L. Antigen delivery to early endosomes eliminates the superiority of human blood BDCA3+ dendritic cells at cross presentation. ACTA ACUST UNITED AC 2013; 210:1049-63. [PMID: 23569326 PMCID: PMC3646496 DOI: 10.1084/jem.20121251] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Human BDCA3(+) dendritic cells (DCs), the proposed equivalent to mouse CD8α(+) DCs, are widely thought to cross present antigens on MHC class I (MHCI) molecules more efficiently than other DC populations. If true, it is unclear whether this reflects specialization for cross presentation or a generally enhanced ability to present antigens on MHCI. We compared presentation by BDCA3(+) DCs with BDCA1(+) DCs using a quantitative approach whereby antigens were targeted to distinct intracellular compartments by receptor-mediated internalization. As expected, BDCA3(+) DCs were superior at cross presentation of antigens delivered to late endosomes and lysosomes by uptake of anti-DEC205 antibody conjugated to antigen. This difference may reflect a greater efficiency of antigen escape from BDCA3(+) DC lysosomes. In contrast, if antigens were delivered to early endosomes through CD40 or CD11c, BDCA1(+) DCs were as efficient at cross presentation as BDCA3(+) DCs. Because BDCA3(+) DCs and BDCA1(+) DCs were also equivalent at presenting peptides and endogenously synthesized antigens, BDCA3(+) DCs are not likely to possess mechanisms for cross presentation that are specific to this subset. Thus, multiple DC populations may be comparably effective at presenting exogenous antigens to CD8(+) T cells as long as the antigen is delivered to early endocytic compartments.
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Internalization and endosomal degradation of receptor-bound antigens regulate the efficiency of cross presentation by human dendritic cells. Blood 2012; 120:2011-20. [PMID: 22791285 DOI: 10.1182/blood-2012-01-402370] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dendritic cells (DCs) can capture extracellular antigens and load resultant peptides on to MHC class I molecules, a process termed cross presentation. The mechanisms of cross presentation remain incompletely understood, particularly in primary human DCs. One unknown is the extent to which antigen delivery to distinct endocytic compartments determines cross presentation efficiency, possibly by influencing antigen egress to the cytosol. We addressed the problem directly and quantitatively by comparing the cross presentation of identical antigens conjugated with antibodies against different DC receptors that are targeted to early or late endosomes at distinct efficiencies. In human BDCA1+ and monocyte-derived DCs, CD40 and mannose receptor targeted antibody conjugates to early endosomes, whereas DEC205 targeted antigen primarily to late compartments. Surprisingly, the receptor least efficient at internalization, CD40, was the most efficient at cross presentation. This did not reflect DC activation by CD40, but rather its relatively poor uptake or intra-endosomal degradation compared with mannose receptor or DEC205. Thus, although both early and late endosomes appear to support cross presentation in human DCs, internalization efficiency, especially to late compartments, may be a negative predictor of activity when selecting receptors for vaccine development.
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16
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Haves-Zburof D, Paperna T, Gour-Lavie A, Mandel I, Glass-Marmor L, Miller A. Cathepsins and their endogenous inhibitors cystatins: expression and modulation in multiple sclerosis. J Cell Mol Med 2012; 15:2421-9. [PMID: 21143385 PMCID: PMC3822953 DOI: 10.1111/j.1582-4934.2010.01229.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Cathepsins are involved in a variety of physiological processes including antigen processing and presentation and extracellular matrix degradation. In the present study, we evaluated whether expression levels of cathepsins S and B and their inhibitors cystatins B and C are affected by multiple sclerosis (MS) disease state (relapse and remission) and therapies (interferon-β[IFN-β] and the glucocorticoid [GC] methylprednisolone), and whether they are associated with the IFN-β response phenotype. Real-time PCR was employed to compare RNA expression levels in peripheral blood leucocytes (PBLs) and ELISA to determine serum protein levels of MS patients and matched healthy individuals. Cathepsin S RNA was higher in MS patients in the relapse state compared to controls (by 74%, P= 3 × 10−5, n= 30 versus n= 18) with a similar increase observed in serum (66%, P= 0.002, n= 18 versus n= 20). GC treatment reduced cathepsin S levels in PBL RNA (by 44%, P= 6 × 10−6, n= 27) and serum proteins (by 27%, P= 1 × 10−5, n= 26), reduced the serum protein levels of pro-cathepsin B (by 8%, P= 0.0007, n= 23), and in parallel increased the serum levels of their inhibitor cystatin C (by 82%, P= 8 × 10−6, n= 26). IFN-β therapy significantly elevated the RNA levels (n= 16) of cathepsin B (by 16%, P= 0.03), cystatin B (44%, P= 0.004) and cystatin C (48%, P= 0.011). In the serum, only cathepsin S levels were reduced by IFN-β (16%, P= 0.006, n= 25). Interestingly, pre-treatment serum cathepsin S/cystatin C ratio was higher in ‘good responders’ to IFN-β therapy compared to patients without a good response (by 94%, P= 0.003). These results suggest that cathepsin S and cystatin C may contribute to disease activity in MS, specifically in a subgroup of patients that are responsive to IFN-β therapy, and that these proteins should be further evaluated as biomarkers in MS.
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Affiliation(s)
- Dana Haves-Zburof
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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17
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Stoeckle C, Quecke P, Rückrich T, Burster T, Reich M, Weber E, Kalbacher H, Driessen C, Melms A, Tolosa E. Cathepsin S dominates autoantigen processing in human thymic dendritic cells. J Autoimmun 2012; 38:332-43. [PMID: 22424724 DOI: 10.1016/j.jaut.2012.02.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 02/25/2012] [Accepted: 02/26/2012] [Indexed: 10/28/2022]
Abstract
The interaction of developing thymocytes with peptide-MHC complexes on thymic antigen presenting cells (APC) is crucial for T cell development, both for positive selection of "useful" thymocytes as well as negative selection of autoreactive thymocytes to prevent autoimmunity. The peptides presented on MHC II molecules are generated by lysosomal proteases such as the cathepsins. At the same time, lysosomal proteases will also destroy other potential T cell epitopes from self-antigens. This will lead to a lack of presentation on negatively selecting thymic antigen presenting cells and consequently, escape of autoreactive T cells recognizing these epitopes. In order to understand the processes that govern generation or destruction of self-epitopes in thymic APC, we studied the antigen processing machinery and epitope processing in the human thymus. We find that each type of thymic APC expresses a different signature of lysosomal proteases, providing indirect evidence that positive and negative selection of CD4(+) T cells might occur on different sets of peptides, in analogy to what has been proposed for CD8(+) T cells. We also find that myeloid dendritic cells (DC) are more efficient in processing autoantigen than plasmacytoid DC. In addition, we observed that cathepsin S plays a central role in processing of the autoantigens myelin basic protein and proinsulin in thymic dendritic cells. Cathepsin S destroyed a number of known T cell epitopes, which would be expected to result in lack of presentation and consequently, escape of autoreactive T cells. Cathepsin S therefore appears to be an important factor that influences selection of autoreactive T cells.
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Affiliation(s)
- Christina Stoeckle
- Hertie Institute for Clinical Brain Research, University of Tuebingen, Germany.
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18
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Phagosomal proteolysis in dendritic cells is modulated by NADPH oxidase in a pH-independent manner. EMBO J 2011; 31:932-44. [PMID: 22157818 DOI: 10.1038/emboj.2011.440] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 11/04/2011] [Indexed: 12/23/2022] Open
Abstract
The level of proteolysis within phagosomes of dendritic cells (DCs) is thought to be tightly regulated, as it directly impacts the cell's efficiency to process antigen. Activity of the antimicrobial effector NADPH oxidase (NOX2) has been shown to reduce levels of proteolysis within phagosomes of both macrophages and DCs. However, the proposed mechanisms underlying these observations in these two myeloid cell lineages are dissimilar. Using real-time analysis of lumenal microenvironmental parameters within phagosomes in live bone marrow-derived DCs, we show that the levels of phagosomal proteolysis are diminished in the presence of NOX2 activity, but in contrast to previous reports, the acidification of the phagosome is largely unaffected. As found in macrophages, we show that NOX2 controls phagosomal proteolysis in DCs through redox modulation of local cysteine cathepsins. Aspartic cathepsins were unaffected by redox conditions, indicating that NOX2 skews the relative protease activities in these antigen processing compartments. The ability of DC phagosomes to reduce disulphides was also compromised by NOX2 activity, implicating this oxidase in the control of an additional antigen processing chemistry of DCs.
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19
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Reich M, Zou F, Sieńczyk M, Oleksyszyn J, Boehm BO, Burster T. Invariant chain processing is independent of cathepsin variation between primary human B cells/dendritic cells and B-lymphoblastoid cells. Cell Immunol 2011; 269:96-103. [PMID: 21543057 DOI: 10.1016/j.cellimm.2011.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 02/16/2011] [Accepted: 03/13/2011] [Indexed: 01/01/2023]
Abstract
As part of the endocytic antigen processing pathway, proteolytic cleavage of the invariant chain (Ii) is important for the generation of class II-associated invariant chain peptide (CLIP). CLIP remains associated with the major histocompatibility complex (MHC) class II molecule to prevent premature loading of antigenic peptides. Cysteine proteases, such as Cathepsin S (CatS), CatL, or CatV, play a pivotal role in the final stage of Ii degradation depending on the cell type studied. Less is known regarding the early stages of Ii processing. We therefore explored whether the serine protease CatG is involved in the initial step of Ii degradation in primary antigen presenting cells (APC), since the cathepsin distribution differs between primary APC and cell lines. While primary human B cells and dendritic cells (DC) do harbor CatG, this protease is absent in B-lymphoblastoid cells (BLC) or monocyte-derived DC generated in vitro. In addition, other proteases, such as CatC, CatL, and the asparagine endoprotease (AEP), are active in BLC and monocyte-derived DC. Here we demonstrate that CatG progressively degraded Ii in vitro resulting in several intermediates. However, pharmacological inhibition of CatG in primary B cells and DC did not alter Ii processing, indicating that CatG is dispensable in Ii degradation. Interestingly, stalling of cysteine proteases by inhibition in BLC vs. primary B cells and DC did not result in any differences in the generation of distinct Ii intermediates between the cells tested, suggesting that Ii processing is independent of the cathepsin variation within professional human APC.
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Affiliation(s)
- Michael Reich
- Division of Endocrinology and Diabetes, Center for Internal Medicine, University Medical Center Ulm, Ulm, Germany
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20
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Teunissen MBM, Haniffa M, Collin MP. Insight into the immunobiology of human skin and functional specialization of skin dendritic cell subsets to innovate intradermal vaccination design. Curr Top Microbiol Immunol 2011; 351:25-76. [PMID: 21833835 DOI: 10.1007/82_2011_169] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Dendritic cells (DC) are the key initiators and regulators of any immune response which determine the outcome of CD4(+) and CD8(+) T-cell responses. Multiple distinct DC subsets can be distinguished by location, phenotype, and function in the homeostatic and inflamed human skin. The function of steady-state cutaneous DCs or recruited inflammatory DCs is influenced by the surrounding cellular and extracellular skin microenvironment. The skin is an attractive site for vaccination given the extended local network of DCs and the easy access to the skin-draining lymph nodes to generate effector T cells and immunoglobulin-producing B cells for long-term protective immunity. In the context of intradermal vaccination we describe in this review the skin-associated immune system, the characteristics of the different skin DC subsets, the mechanism of antigen uptake and presentation, and how the properties of DCs can be manipulated. This knowledge is critical for the development of intradermal vaccine strategies and supports the concept of intradermal vaccination as a superior route to the conventional intramuscular or subcutaneous methods.
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Affiliation(s)
- M B M Teunissen
- Department of Dermatology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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21
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Stoeckle C, Tolosa E. Antigen processing and presentation in multiple sclerosis. Results Probl Cell Differ 2010; 51:149-72. [PMID: 19582405 DOI: 10.1007/400_2009_22] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
CD4(+) T cells play a central role in the pathogenesis of multiple sclerosis (MS). Generation, activation and effector function of these cells crucially depends on their interaction with MHC II-peptide complexes displayed by antigen presenting cells (APC). Processing and presentation of self antigens by different APC therefore influences the disease course at all stages. Selection by thymic APC leads to the generation of autoreactive T cells, which can be activated by peripheral APC. Reactivation by central nervous system APC leads to the initiation of the inflammatory response resulting in demyelination. In this review we will focus on how MHC class II antigenic epitopes are created by different APC from the thymus, the periphery and from the brain, and will discuss the relevance of the balance between creation and destruction of such epitopes in the context of MS. A solid understanding of these processes offers the possibility for designing future therapeutic strategies.
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Affiliation(s)
- Christina Stoeckle
- Department of General Neurology, Hertie Institute for Clinical Brain Research, Otfried-Mueller-Str. 27, 72076, Tuebingen, Germany.
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22
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Matthews SP, Werber I, Deussing J, Peters C, Reinheckel T, Watts C. Distinct protease requirements for antigen presentation in vitro and in vivo. THE JOURNAL OF IMMUNOLOGY 2010; 184:2423-31. [PMID: 20164435 DOI: 10.4049/jimmunol.0901486] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Asparagine endopeptidase (AEP) or legumain is a potentially important Ag-processing enzyme that introduces limited cleavages that trigger unfolding and class II MHC binding of different Ag substrates. AEP is necessary and sufficient for optimal processing and presentation of the tetanus toxin C fragment (TTCF) Ag in vitro, but its importance has not been tested in vivo. Surprisingly, virtually normal T cell and Ab responses to TTCF were mounted in AEP-deficient mice when examined 10 d after immunization. This was the case when TTCF was emulsified with CFA, adsorbed onto alum, or expressed within live Salmonella typhimurium. In addition, the dominant Ab and T cell determinants recognized in TTCF were essentially unchanged in AEP-deficient mice. These data are explained, at least in part, by the much lower levels of AEP expressed in primary murine APCs compared with immortalized B cell lines. Even so, the initial in vivo kinetics of TTCF presentation were slower in AEP-deficient mice and, as expected, boosting AEP levels in primary APCs enhanced and accelerated TTCF processing and presentation in vitro. Thus, AEP remains the protease of choice for TTCF processing; however, in its absence, other enzymes can substitute to enable slower, but equally robust, adaptive immune responses. Moreover, clear relationships between Ags and processing proteases identified from short-term in vitro processing and presentation studies do not necessarily predict an absolute in vivo dependency on those processing enzymes, not least because they may be expressed at strikingly different levels in vitro versus in vivo.
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Affiliation(s)
- Stephen P Matthews
- Division of Cell Biology and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
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23
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Burster T, Boehm BO. Processing and presentation of (pro)-insulin in the MHC class II pathway: the generation of antigen-based immunomodulators in the context of type 1 diabetes mellitus. Diabetes Metab Res Rev 2010; 26:227-38. [PMID: 20503254 DOI: 10.1002/dmrr.1090] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Both CD4(+) and CD8(+) T lymphocytes play a crucial role in the autoimmune process leading to T1D. Dendritic cells take up foreign antigens and autoantigens; within their endocytic compartments, proteases degrade exogenous antigens for subsequent presentation to CD4(+) T cells via MHC class II molecules. A detailed understanding of autoantigen processing and the identification of autoantigenic T cell epitopes are crucial for the development of antigen-based specific immunomodulators. APL are peptide analogues of auto-immunodominant T cell epitopes that bind to MHC class II molecules and can mediate T cell activation. However, APL can be rapidly degraded by proteases occurring in the extracellular space and inside cells, substantially weakening their efficiency. By contrast, protease-resistant APL function as specific immunomodulators and can be used at low doses to examine the functional plasticity of T cells and to potentially interfere with autoimmune responses. Here, we review the latest achievements in (pro)-insulin processing in the MHC class II pathway and the generation of APL to mitigate autoreactive T cells and to activate Treg cells.
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Affiliation(s)
- Timo Burster
- Division of Endocrinology and Diabetes, Center for Internal Medicine, University Medical Center Ulm, Ulm, Germany.
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24
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Baumgartner CK, Malherbe LP. Regulation of CD4 T-cell receptor diversity by vaccine adjuvants. Immunology 2010; 130:16-22. [PMID: 20331477 DOI: 10.1111/j.1365-2567.2010.03265.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
New vaccines based on soluble recombinant antigens (Ags) require adjuvants to elicit long-lasting protective humoral and cellular immunity. Despite the importance of CD4 T helper cells for the generation of long-lived memory B and CD8 T cells, the impact of adjuvants on CD4 T-cell responses is still poorly understood. Adjuvants are known to promote dendritic cell (DC) maturation and migration to secondary lymphoid organs where they present foreign peptides bound to class II major histocompatibility complex molecules (pMHCII) to naïve CD4 T cells. Random and imprecise rearrangements of genetic elements during thymic development ensure that a vast amount of T-cell receptors (TCRs) are present in the naïve CD4 T-cell repertoire. Ag-specific CD4 T cells are selected from this vast pre-immune repertoire based on the affinity of their TCR for pMHCII. Here, we review the evidence demonstrating a link between the adjuvant and the specificity and clonotypic diversity of the CD4 T-cell response, and consider the potential mechanisms at play.
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25
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Burster T, Macmillan H, Hou T, Schilling J, Truong P, Boehm BO, Zou F, Lau K, Strohman M, Schaffert S, Busch R, Mellins ED. Masking of a cathepsin G cleavage site in vivo contributes to the proteolytic resistance of major histocompatibility complex class II molecules. Immunology 2010; 130:436-46. [PMID: 20331476 DOI: 10.1111/j.1365-2567.2010.03247.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
SUMMARY The expression of major histocompatibility complex class II (MHC II) molecules is post-translationally regulated by endocytic protein turnover. Here, we identified the serine protease cathepsin G (CatG) as an MHC II-degrading protease by in vitro screening and examined its role in MHC II turnover in vivo. CatG, uniquely among endocytic proteases tested, initiated cleavage of detergent-solubilized native and recombinant soluble MHC II molecules. CatG cleaved human leukocyte antigen (HLA)-DR isolated from both HLA-DM-expressing and DM-null cells. Even following CatG cleavage, peptide binding was retained by pre-loaded, soluble recombinant HLA-DR. MHC II cleavage occurred on the loop between fx1 and fx2 of the membrane-proximal beta2 domain. All allelic variants of HLA-DR tested and murine I-A(g7) class II molecules were susceptible, whereas murine I-E(k) and HLA-DM were not, consistent with their altered sequence at the P1' position of the CatG cleavage site. CatG effects were reduced on HLA-DR molecules with DRB mutations in the region implicated in interaction with HLA-DM. In contrast, addition of CatG to intact B-lymphoblastoid cell lines (B-LCLs) did not cause degradation of membrane-bound MHC II. Moreover, inhibition or genetic ablation of CatG in primary antigen-presenting cells did not cause accumulation of MHC II molecules. Thus, in vivo, the CatG cleavage site is sterically inaccessible or masked by associated molecules. A combination of intrinsic and context-dependent proteolytic resistance may allow peptide capture by MHC II molecules in harshly proteolytic endocytic compartments, as well as persistent antigen presentation in acute inflammatory settings with extracellular proteolysis.
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Affiliation(s)
- Timo Burster
- Division of Endocrinology and Diabetes, Department of Internal Medicine I, Ulm University, Ulm, Germany.
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26
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Burster T, Macmillan H, Hou T, Boehm BO, Mellins ED. Cathepsin G: roles in antigen presentation and beyond. Mol Immunol 2009; 47:658-65. [PMID: 19910052 DOI: 10.1016/j.molimm.2009.10.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 10/02/2009] [Accepted: 10/06/2009] [Indexed: 12/19/2022]
Abstract
Contributions from multiple cathepsins within endosomal antigen processing compartments are necessary to process antigenic proteins into antigenic peptides. Cysteine and aspartyl cathepsins have been known to digest antigenic proteins. A role for the serine protease, cathepsin G (CatG), in this process has been described only recently, although CatG has long been known to be a granule-associated proteolytic enzyme of neutrophils. In line with a role for this enzyme in antigen presentation, CatG is found in endocytic compartments of a variety of antigen presenting cells. CatG is found in primary human monocytes, B cells, myeloid dendritic cells 1 (mDC1), mDC2, plasmacytoid DC (pDC), and murine microglia, but is not expressed in B cell lines or monocyte-derived DC. Purified CatG can be internalized into endocytic compartments in CatG non-expressing cells, widening the range of cells where this enzyme may play a role in antigen processing. Functional assays have implicated CatG as a critical enzyme in processing of several antigens and autoantigens. In this review, historical and recent data on CatG expression, distribution, function and involvement in disease will be summarized and discussed, with a focus on its role in antigen presentation and immune-related events.
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Affiliation(s)
- Timo Burster
- Division of Endocrinology and Diabetes, Department of Internal Medicine I, Ulm University, Ulm, Germany.
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27
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Abstract
It has previously been shown that a approximately 27 kDa serine protease of Schistosoma mansoni larvae, the cercarial elastase (CE), was a poor immunogen in as much as it failed to induce an antibody response. The CE has a critical role in enabling schistosome larvae to penetrate the skin of their definitive hosts, so the apparently poor immunogenicity of this enzyme is clearly of interest. To understand its lack of immunogenicity better and in particular to determine whether it is related to its proteolytic activity, we have measured antibody responses of mice to three different serine proteases. Groups of mice were immunized with porcine pancreatic trypsin (TRY), chymotrypsin (CHY) or elastase (ELA) and the resulting antibody response compared with antibody responses to two non-protease antigens, chicken egg albumin (OVA) and Schistosoma japonicum glutathione S-transferase (GST), all being administered with alum as an adjuvant. Of 12 mice that were injected five times at 14 day intervals with TRY, only one produced antibody reactive with this enzyme in ELISA. Immunizations with CHY or ELA induced somewhat better antibody responses than TRY, but the responses to the first and second injections of these two proteases nevertheless seemed comparatively lower than the responses to GST. Induction of antibody responses by OVA and GST was not affected when TRY was injected concomitantly. Thus, the antibody response to one of the serine proteases used in this study, mammalian trypsin, was anomalous.
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Affiliation(s)
- H Y Darani
- Department of Parasitology, Faculty of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran.
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28
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Martinez O, Johnson J, Manicassamy B, Rong L, Olinger GG, Hensley LE, Basler CF. Zaire Ebola virus entry into human dendritic cells is insensitive to cathepsin L inhibition. Cell Microbiol 2009; 12:148-57. [PMID: 19775255 DOI: 10.1111/j.1462-5822.2009.01385.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cathepsins B and L contribute to Ebola virus (EBOV) entry into Vero cells and mouse embryonic fibroblasts. However, the role of cathepsins in EBOV-infection of human dendritic cells (DCs), important targets of infection in vivo, remains undefined. Here, EBOV-like particles containing a beta-lactamase-VP40 fusion reporter and Ebola virus were used to demonstrate the cathepsin dependence of EBOV entry into human monocyte-derived DCs. However, while DC infection is blocked by cathepsin B inhibitor, it is insensitive to cathepsin L inhibitor. Furthermore, DCs pre-treated for 48 h with TNFalpha were generally less susceptible to entry and infection by EBOV. This decrease in infection was associated with a decrease in cathepsin B activity. Thus, cathepsin L plays a minimal, if any, role in EBOV infection in human DCs. The inflammatory cytokine TNFalpha modulates cathepsin B activity and affects EBOV entry into and infection of human DCs.
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Affiliation(s)
- Osvaldo Martinez
- Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA
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29
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Reich M, Lesner A, Legowska A, Sieńczyk M, Oleksyszyn J, Boehm BO, Burster T. Application of specific cell permeable cathepsin G inhibitors resulted in reduced antigen processing in primary dendritic cells. Mol Immunol 2009; 46:2994-9. [PMID: 19615749 DOI: 10.1016/j.molimm.2009.06.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 06/16/2009] [Indexed: 11/15/2022]
Abstract
The serine protease cathepsin G (CatG) is expressed in primary antigen-presenting cells and regulates autoantigen processing in CatG pre-loaded fibroblasts. To further investigate the function of CatG in the major histocompatibility complex (MHC) class II loading compartments, a specific, cell permeable CatG-inhibitor is needed. In this study, several CatG-inhibitors were tested for their ability to penetrate the cell membrane of peripheral blood mononuclear cells (PBMC). We find that the commercially available reversible CatG-specific inhibitor I (CatG inhibitor) and the irreversible Suc-Val-Pro-Phe(P) (OPh)(2) (Suc-VPF) are both cell permeable and specifically inhibit intracellular CatG in the PBMC. Furthermore, selective inhibition of CatG resulted in reduced tetanus toxin C-fragment (TTC) and hemagglutinin (HA) processing and presentation to CD4(+) T cells. We conclude that these CatG inhibitors can be used for both antigen-processing studies and for modulation of T cell response in situ and in vivo.
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Affiliation(s)
- Michael Reich
- Catheomics, Division of Endocrinology and Diabetes, Department of Internal Medicine I, University Medical Center Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
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30
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Reich M, Wieczerzak E, Jankowska E, Palesch D, Boehm BO, Burster T. Specific cathepsin B inhibitor is cell-permeable and activates presentation of TTC in primary human dendritic cells. Immunol Lett 2009; 123:155-9. [PMID: 19428564 DOI: 10.1016/j.imlet.2009.03.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 03/10/2009] [Accepted: 03/10/2009] [Indexed: 10/21/2022]
Abstract
Cathepsins of the cysteine, aspartyl, and serine classes are involved in antigen processing in the class II major histocompatibility complex (MHC) loading compartment. Investigation of these proteases in living cells is difficult to perform due to the lack of highly specific cell-permeable inhibitors. Recently, a highly selective cathepsin B (CatB) inhibitor, Z-Arg-Leu-Arg-alpha-aza-glycyl-Ile-Val-OMe (ZRLR), was described. We found that ZRLR is cell-permeable and specifically inhibits CatB, in contrast to the CatB inhibitor, CA074-OMe, which blocks cysteine cathepsins in addition to CatB in primary human antigen-presenting cells (APC). Furthermore, we compared both CA074-OMe and ZRLR in the ability to alter tetanus toxin C-fragment (TTC) presentation to T cells by different APC. As a result, we found enhanced presentation of TTC in the presence of ZRLR, as determined by detection of pro-inflammatory cytokines. We conclude that ZRLR is a specific, cell-permeable CatB inhibitor which can be used for antigen presenting studies in situ.
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Affiliation(s)
- Michael Reich
- Catheomics, Division of Endocrinology and Diabetes, Department of Internal Medicine I, University Medical Center Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
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Cathepsin E regulates the presentation of tetanus toxin C-fragment in PMA activated primary human B cells. Biochem Biophys Res Commun 2008; 377:1299-303. [DOI: 10.1016/j.bbrc.2008.10.162] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Accepted: 10/30/2008] [Indexed: 11/23/2022]
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32
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Stoeckle C, Sommandas V, Adamopoulou E, Belisle K, Schiekofer S, Melms A, Weber E, Driessen C, Boehm BO, Tolosa E, Burster T. Cathepsin G is differentially expressed in primary human antigen-presenting cells. Cell Immunol 2008; 255:41-5. [PMID: 19036358 DOI: 10.1016/j.cellimm.2008.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 10/06/2008] [Accepted: 10/08/2008] [Indexed: 11/18/2022]
Abstract
Cathepsins are required for the processing of antigens in order to make them suitable for loading on major histocompatibility complex (MHC) class II molecules, for subsequent presentation to CD4(+) T cells. It was shown that antigen processing in monocyte-derived dendritic cells (DC), a commonly used DC model, is different from that of primary human DC. Here, we report that the two subsets of human myeloid DC (mDC) and plasmacytoid DC (pDC) differ in their cathepsin distribution. The serine protease cathepsin G (CatG) was detected in mDC1, mDC2, pDC, cortical thymic epithelial cells (cTEC) and high levels of CatG were determined in pDC. To address the role of CatG in the processing and presentation of a Multiple Sclerosis-associated autoantigen myelin basic protein (MBP), we used a non-CatG expressing fibroblast cell line and fibroblasts, which were preloaded with purified CatG. We find that preloading fibroblasts with CatG results in a decrease of MBP84-98-specific T cell proliferation, when compared to control cells. Our data suggest a different processing signature in primary human antigen-presenting cells and CatG may be of functional importance.
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Affiliation(s)
- Christina Stoeckle
- Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
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33
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Kessler T, Reich M, Jahn G, Tolosa E, Beck A, Kalbacher H, Overkleeft H, Schempp S, Driessen C. Human cytomegalovirus infection interferes with major histocompatibility complex type II maturation and endocytic proteases in dendritic cells at multiple levels. J Gen Virol 2008; 89:2427-2436. [PMID: 18796710 DOI: 10.1099/vir.0.2008/001610-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Human cytomegalovirus (HCMV) infection suppresses cellular immunity and results in viral persistence. Dendritic cells (DCs) are susceptible to HCMV, and the development and immune function of HCMV-infected DCs are impaired in vitro. HCMV-derived proteins interfere with different aspects of major histocompatibility complex type II (MHC II) maturation and function in genetically engineered cellular models. This study directly analysed the effect of HCMV on the MHC II-associated antigen processing and presentation machinery in HCMV-infected human DCs in vitro. HCMV-infected DCs failed to mature newly synthesized MHC II to the final stage of SDS-stable MHC II alphabeta dimer/peptide complexes, in contrast to mock-infected controls. MHC II biosynthesis was delayed and reduced, whilst MHC II stability remained unchanged. MHC II surface expression was decreased in the late phase of HCMV infection. In addition, infected DCs decreased the transcription rate of the MHC II-associated proteases cathepsins S, Z, B, H and L and asparagine-specific endopeptidase (AEP). This translated into reduced protein expression of cathepsins H and S, as well as AEP, and less-efficient proteolytic degradation of a peptide substrate by endocytic proteases from HCMV-infected DCs in vitro. Thus, HCMV infection interferes with MHC II biosynthesis and maturation, as well as with the expression and function of endocytic proteases in infected DCs.
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Affiliation(s)
- Tobias Kessler
- Department of Virology, University of Tübingen, Tübingen, Germany
| | - Michael Reich
- Department of Medicine II, University of Tübingen, Tübingen, Germany
| | - Gerhard Jahn
- Department of Virology, University of Tübingen, Tübingen, Germany
| | - Eva Tolosa
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Alexander Beck
- Department of Medicine IV, University of Tübingen, Tübingen, Germany
| | - Hubert Kalbacher
- Natural Sciences Research Centre, University of Tübingen, Tübingen, Germany
| | - Herman Overkleeft
- Leiden Institute of Chemistry, University of Leiden, Leiden, The Netherlands
| | - Susanne Schempp
- Department of Virology, University of Tübingen, Tübingen, Germany
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Villiers CL, Cretin F, Lefebvre N, Marche PN, Villiers MB. A new role for complement C3: regulation of antigen processing through an inhibitory activity. Mol Immunol 2008; 45:3509-16. [PMID: 18585783 DOI: 10.1016/j.molimm.2008.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Revised: 05/14/2008] [Accepted: 05/20/2008] [Indexed: 11/15/2022]
Abstract
Increasing evidence underlines the involvement of complement component C3 in the establishment of acquired immunity which appears to play a complex role and to act at different levels. As antigen proteolysis by antigen presenting cells is a key event in the control of antigen presentation efficiency, and consequently in the quality of the immune response, we investigated whether C3 could modulate this step. Our results demonstrate for the first time that C3 can interfere with antigen proteolysis: (i) proteolysis of tetanus toxin (TT) by the lysosomal fraction from a human monocytic cell line (U937) is impaired in the presence of C3, (ii) this effect is C3-specific and involves the C3c fragment of the protein, (iii) C3c is effective even after disulfide disruption, but none of its three constitutive peptides is individually accountable for this inhibitory effect and (iv) the target-protease(s) exhibit(s) a serine-protease activity. The physiological relevance of our results is demonstrated by experiments showing a subcellular colocalisation of TT and C3 after their uptake by U937 and the reduction of TT proteolysis once internalised together with C3. These results highlight a novel role for C3 that broadens its capacity to modulate acquired immune response.
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Burster T, Marin-Esteban V, Boehm BO, Dunn S, Rotzschke O, Falk K, Weber E, Verhelst SHL, Kalbacher H, Driessen C. Design of protease-resistant myelin basic protein-derived peptides by cleavage site directed amino acid substitutions. Biochem Pharmacol 2007; 74:1514-23. [PMID: 17803968 DOI: 10.1016/j.bcp.2007.07.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 06/23/2007] [Accepted: 07/16/2007] [Indexed: 10/23/2022]
Abstract
Multiple Sclerosis (MS) is considered to be a T cell-mediated autoimmune disease. An attractive strategy to prevent activation of autoaggressive T cells in MS, is the use of altered peptide ligands (APL), which bind to major histocompatibility complex class II (MHC II) molecules. To be of clinical use, APL must be capable of resisting hostile environments including the proteolytic machinery of antigen presenting cells (APC). The current design of APL relies on cost- and labour-intensive strategies. To overcome these major drawbacks, we used a deductive approach which involved modifying proteolytic cleavage sites in APL. Cleavage site-directed amino acid substitution of the autoantigen myelin basic protein (MBP) resulted in lysosomal protease-resistant, high-affinity binding peptides. In addition, these peptides mitigated T cell activation in a similar fashion as conventional APL. The strategy outlined allows the development of protease-resistant APL and provides a universal design strategy to improve peptide-based immunotherapeutics.
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Affiliation(s)
- Timo Burster
- Department of Medicine II, University of Tübingen, Tübingen, Germany.
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Abu-Eisha HM, Butt NM, Clark RE, Christmas SE. Evidence that a BCR-ABL fusion peptide does not induce lymphocyte proliferation or cytokine production in vitro. Leuk Res 2007; 31:1675-81. [PMID: 17324459 DOI: 10.1016/j.leukres.2007.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 12/22/2006] [Accepted: 01/14/2007] [Indexed: 10/23/2022]
Abstract
The BCR-ABL fusion protein is characteristic of chronic myeloid leukaemia and may be an effective tumour-specific antigen. CD8+ T cell responses to BCR-ABL fusion peptides have been reported in normal subjects and CML patients but CD4+ T cell responses have been less well characterised. Here, the 23-mer e14a2 fusion peptide VHSATGFKQSSKALQRPVASDFE has been used to stimulate T cell responses. Most normal subjects and CML patients showed no proliferative responses to this peptide, with stimulation indices not significantly greater than 1.0. Following a second stimulation with the same peptide, small proliferative responses were obtained in normal subjects but not CML patients. These responses were not improved following a third stimulation with 23-mer peptide, nor by using mature autologous dendritic cells to present the peptide. Intracellular interferon-gamma production by CD4+ T cells was also not induced by the 23-mer e14a2 peptide. Hence, this e14a2 peptide does not stimulate CD4+ T cell proliferation in vitro in most normal subjects or CML patients. The precise sequence of amino acids may be critical in defining immunogenicity for CD4+ T cell responses against BCR-ABL peptides.
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Burster T, Beck A, Poeschel S, Øren A, Baechle D, Reich M, Roetzschke O, Falk K, Boehm BO, Youssef S, Kalbacher H, Overkleeft H, Tolosa E, Driessen C. Interferon-gamma regulates cathepsin G activity in microglia-derived lysosomes and controls the proteolytic processing of myelin basic protein in vitro. Immunology 2007; 121:82-93. [PMID: 17302735 PMCID: PMC2265925 DOI: 10.1111/j.1365-2567.2007.02540.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The serine protease cathepsin (Cat) G dominates the proteolytic processing of the multiple sclerosis (MS)-associated autoantigen myelin basic protein (MBP) in lysosomes from primary human B cells and dendritic cells. This is in contrast to B-lymphoblastoid cell lines, where the asparagine endopeptidase (AEP) is responsible for this task. We have analysed microglia-derived lysosomal proteases for their ability to process MBP in vitro. In lysosomes derived from primary murine microglia, CatD, CatS, AEP and CatG were involved in the processing of MBP. Interestingly, when microglia were treated with interferon-gamma to mimic a T helper type 1-biased cytokine milieu in MS, CatG was drastically down-regulated, in contrast to CatS, CatB, CatL, CatD or AEP. This resulted in significantly increased stability of MBP and a selective lack of CatG-derived proteolytic fragments; however, it did not affect the gross pattern of MBP processing. Inhibition of serine proteases eliminated the processing differences between lysosomal extracts from resting microglia compared to interferon-stimulated microglia. Thus, the cytokine environment modulates lysosomal proteases in microglia by a selective down-regulation of CatG, leading to decreased MBP-processing by microglia-derived lysosomal proteases in vitro.
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Affiliation(s)
- Timo Burster
- Department of Medicine II, University of Tübingen, Germany.
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Reich M, van Swieten PF, Sommandas V, Kraus M, Fischer R, Weber E, Kalbacher H, Overkleeft HS, Driessen C. Endocytosis targets exogenous material selectively to cathepsin S in live human dendritic cells, while cell-penetrating peptides mediate nonselective transport to cysteine cathepsins. J Leukoc Biol 2007; 81:990-1001. [PMID: 17261546 DOI: 10.1189/jlb.1006600] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The way the MHC II-associated proteolytic system of APC handles exogenous antigen is key to the stimulation of the T cell in infections and immunotherapy settings. Using a cell-impermeable, activity-based probe (ABP) for papain cathepsins, the most abundant type of endocytic proteases, we have simulated the encounter between exogenous antigen and endocytic proteases in live human monocyte-derived dendritic cells (MO-DC). Although cathepsin S (CatS), -B, -H, and -X were active in DC-derived endocytic fractions in vitro, the peptide-size tracer was routed selectively to active CatS after internalization by macropinocytosis. Blocking of the vacuolar adenosine triphosphatase abolished this CatS-selective targeting, and LPS-induced maturation of DC resulted in degradation of active CatS. Conjugation of the ABP to a protein facilitated the delivery to endocytic proteases and resulted in labeling of sizable amounts of CatB and CatX, although CatS still remained the major protease reached by this construct. Conjugation of the probe to a cell-penetrating peptide (CPP) routed the tracer to the entire panel of intracellular cathepsins, independently from endocytosis or LPS stimulation. Thus, different means of internalization result in differential targeting of active cathepsins in live MO-DC. CPP may serve as vehicles to target antigen more efficiently to protease-containing endocytic compartments.
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Affiliation(s)
- Michael Reich
- Department of Medicine II, Institute for Cell Biology, and Medical and Natural Sciences Research Center, University of Tübingen, Germany
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Shim HK, Musson JA, Harper HM, McNeill HV, Walker N, Flick-Smith H, von Delwig A, Williamson ED, Robinson JH. Mechanisms of major histocompatibility complex class II-restricted processing and presentation of the V antigen of Yersinia pestis. Immunology 2006; 119:385-92. [PMID: 16919002 PMCID: PMC1819574 DOI: 10.1111/j.1365-2567.2006.02447.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
We mapped mouse CD4 T-cell epitopes located in three structurally distinct regions of the V antigen of Yersinia pestis. T-cell hybridomas specific for epitopes from each region were generated to study the mechanisms of processing and presentation of V antigen by bone-marrow-derived macrophages. All three epitopes required uptake and/or processing from V antigen as well as presentation to T cells by newly synthesized major histocompatibility complex (MHC) class II molecules over a time period of 3-4 hr. Sensitivity to inhibitors showed a dependence on low pH and cysteine, serine and metalloproteinase, but not aspartic proteinase, activity. The data indicate that immunodominant epitopes from all three structural regions of V antigen were presented preferentially by the classical MHC class II-restricted presentation pathway. The requirement for processing by the co-ordinated activity of several enzyme families is consistent with the buried location of the epitopes in each region of V antigen. Understanding the structure-function relationship of multiple immunodominant epitopes of candidate subunit vaccines is necessary to inform choice of adjuvants for vaccine delivery. In the case of V antigen, adjuvants designed to target it to lysosomes are likely to induce optimal responses to multiple protective T-cell epitopes.
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Affiliation(s)
- Ho-Ki Shim
- Musculoskeletal Research Group, Clinical Medical Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, UK
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