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Papayannakos CJ, DeVoti JA, Israr M, Alsudani H, Bonagura V, Steinberg BM. Extracellular vesicles produced by primary human keratinocytes in response to TLR agonists induce stimulus-specific responses in antigen-presenting cells. Cell Signal 2021; 83:109994. [PMID: 33781846 DOI: 10.1016/j.cellsig.2021.109994] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/15/2022]
Abstract
Cells can communicate through the extracellular vesicles (EVs) they secrete. Pathogen associated molecular patterns (PAMPs), alter the biophysical and communicative properties of EVs released from cells, but the functional consequences of these changes are unknown. Characterization of keratinocyte-derived EVs after poly(I:C) treatment (poly(I:C)-EVs) showed slight differences in levels of EV markers TSG101 and Alix, a loss of CD63 and were positive for autophagosome marker LC3b-II and the cytokine IL36γ compared to EVs from unstimulated keratinocytes (control-EVs). Flagellin treatment (flagellin-EVs) led to an EV marker profile like control-EVs but lacked LC3b-II. Flagellin-EVs also lacked IL-36γ despite nearly identical intracellular levels. While poly(I:C) treatment led to the clear emergence of a > 200 nm diameter EV sub-population, these were not found in flagellin-EVs. EV associated IL-36γ colocalized with LC3b-II in density gradient analysis, equilibrating to 1.10 g/mL, indicating a common EV species. Poly(I:C), but not flagellin, induced intracellular vesicles positive for IL-36γ, LC3b-II, Alix and TSG101, consistent with fusion of autophagosomes and multivesicular bodies. Simultaneous rapamycin and flagellin treatment induced similar intracellular vesicles but was insufficient for the release of IL-36γ+/LC3b-II+ EVs. Finally, a qRT-PCR array screen showed eight cytokine/chemokine transcripts were altered (p < 0.05) in monocyte-derived Langerhans cells (LCs) when stimulated with poly(I:C)-EVs while three were altered when LCs were stimulated with flagellin-EVs compared to control-EVs. After independent confirmation, poly(I:C)-EVs upregulated BMP6 (p = 0.035) and flagellin-EVs upregulated CXCL8 (p = 0.005), VEGFA (p = 0.018) and PTGS2 (p = 0.020) compared to control-EVs. We conclude that exogenous signals derived from pathogens can alter keratinocyte-mediated modulation of the local immune responses by inducing changes in the types of EVs secreted and responses in antigen presenting cells.
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Affiliation(s)
- Christopher J Papayannakos
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra University, Hempstead, NY 11549, USA.
| | - James A DeVoti
- The Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, New York, USA; Department of Pediatrics, Steven and Alexandra Cohen Children's Medical Center of New York, Barbara and Donald Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
| | - Mohd Israr
- The Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, New York, USA
| | - Habeeb Alsudani
- Cold Spring Harbor Laboratory, Cancer Center, Cold Spring Harbor, New York, USA
| | - Vincent Bonagura
- The Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, New York, USA; Department of Pediatrics, Steven and Alexandra Cohen Children's Medical Center of New York, Barbara and Donald Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
| | - Bettie M Steinberg
- The Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, New York, USA; Department of Molecular Medicine, Barbara and Donald Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, United States of America
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Mortaş H, Bilici S, Karakan T. The circadian disruption of night work alters gut microbiota consistent with elevated risk for future metabolic and gastrointestinal pathology. Chronobiol Int 2020; 37:1067-1081. [PMID: 32602753 DOI: 10.1080/07420528.2020.1778717] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Day and night cycles are the most important cue for the central clock of human beings, and they are also important for the gut clock. The aim of the study is to determine the differences in the gut microbiota of rotational shift workers when working the day versus night shift. Fecal samples and other data were collected from 10 volunteer male security officers after 4 weeks of day shift work (07:00-15:00 h) and also after 2 weeks of night shift work (23:00-07:00 h). In total, 20 stool samples were collected for analysis of gut microbiota (10 subjects x 2 work shifts) and stored at -80°C until analysis by 16 S rRNA sequencing. The relative abundances of Bacteroidetes were reduced and those of Actinobacteria and Firmicutes increased when working the night compared to day shift. Faecalibacterium abundance was found to be a biomarker of the day shift work. Dorea longicatena and Dorea formicigenerans were significantly more abundant in individuals when working the night shift. Rotational day and night shift work causes circadian rhythm disturbance with an associated alteration in the abundances of gut microbiota, leading to the concern that such induced alteration of gut microbiota may at least partially contribute to an increased risk of future metabolic syndrome and gastrointestinal pathology.
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Affiliation(s)
- Hande Mortaş
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University , Ankara, Turkey
| | - Saniye Bilici
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University , Ankara, Turkey
| | - Tarkan Karakan
- Department of Internal Medicine Gastroenterology, Faculty of Medicine, Gazi University , Ankara, Turkey
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Jia Y, Anwaar S, Li L, Yin Z, Ye Z, Huang Z. A new target for the treatment of inflammatory bowel disease: Interleukin-37. Int Immunopharmacol 2020; 83:106391. [PMID: 32208166 DOI: 10.1016/j.intimp.2020.106391] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/22/2020] [Accepted: 03/08/2020] [Indexed: 12/19/2022]
Abstract
Interleukin (IL)-37 belongs to the IL-1 cytokine family. It has anti-inflammatory effects on numerous autoimmune diseases such as asthma, psoriasis, inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE), multiple sclerosis (MS) and rheumatoid arthritis (RA). Mechanistically, IL-37 plays an anti-inflammatory role by regulating the expression of inflammatory factors in two ways: binding extracellular receptors IL-18R or transferring into the nucleus with Smad3. IBD is a kind of idiopathic intestinal inflammatory disease with unknown etiology and pathogenesis. Recent researches had proved that IL-37 is negatively involved in the pathogenesis and development of IBD. Among various inflammatory diseases, IL-37 has been shown to regulate inflammatory development by acting on various immune cells such as neutrophils, macrophages (Mϕ), dendritic cells (DCs), T cells and intestinal epithelial cells. This review summarizes the biological role of IL-37, and its immunoregulatory effects on the immune cells, especially anti-inflammatory function in both human and experimental models of IBD.
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Affiliation(s)
- Yuning Jia
- Biological Therapy Institute, Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Department of Immunology, Health Science Center, Shenzhen University, Shenzhen 518055, China
| | - Shoaib Anwaar
- Biological Therapy Institute, Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Department of Immunology, Health Science Center, Shenzhen University, Shenzhen 518055, China
| | - Linyun Li
- Biological Therapy Institute, Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Department of Immunology, Health Science Center, Shenzhen University, Shenzhen 518055, China
| | - Zhihua Yin
- Shenzhen City Futian Qu Rheumatology Specialist Hospital, Shenzhen 518089, China
| | - Zhizhon Ye
- Shenzhen City Futian Qu Rheumatology Specialist Hospital, Shenzhen 518089, China.
| | - Zhong Huang
- Biological Therapy Institute, Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Department of Immunology, Health Science Center, Shenzhen University, Shenzhen 518055, China.
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Günaltay S, Ghiboub M, Hultgren O, Hörnquist EH. Reduced IL-37 Production Increases Spontaneous Chemokine Expressions in Colon Epithelial Cells. Dig Dis Sci 2017; 62:1204-1215. [PMID: 28044228 PMCID: PMC5397456 DOI: 10.1007/s10620-016-4422-9] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/16/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND AIM Microscopic colitis, comprising collagenous colitis and lymphocytic colitis, is a common cause of chronic diarrhea. Previously, we showed enhanced chemokine productions in microscopic colitis patients, indicating dysregulated immune cell chemotaxis in the immunopathogenesis. We also showed decreased mRNA of IL-37, mainly regarded as an anti-inflammatory cytokine, in the colonic mucosa of these patients, potentially an important factor for the chronicity of the colitis. Our aim in this study was to understand the possible role of IL-37 in chemokine production using a cell line model. METHODS A colon epithelial cell line, T84, was stimulated with the TLR5 ligand flagellin. IL-37 protein production was reduced 20% using the CRISPR/Cas9 system, and the changes in chemokine mRNA and protein expressions were compared to cells transfected with empty plasmid. RESULTS The 20% reduction in IL-37 protein levels spontaneously increased CCL5, CXCL8, CXCL10, and CXCL11 mRNA and protein expressions. CCL2 mRNA and protein levels were enhanced upon TLR5 stimulation. CCL3, CCL20, and CX3CL1 mRNA expressions were increased either spontaneously or following TLR5 stimulation, whereas CCL4 and CCL22 mRNA expressions were significantly decreased. CONCLUSIONS Even a minor decrease in the ability of colon epithelial cells to produce IL-37 results in altered chemokine expression, mainly an increase in the production of several chemokines. Our results indicate that a decreased IL-37 expression by colon epithelial cells may be an important factor for increasing the recruitment of immune cells and subsequently developing microscopic colitis.
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Affiliation(s)
- Sezin Günaltay
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, 70182 Örebro, Sweden
| | - Mohammed Ghiboub
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, 70182 Örebro, Sweden ,Academic Medical Center, Tytgat Institute for Liver and Intestinal Research, Amsterdam University, 1105 BK Amsterdam, The Netherlands
| | - Olof Hultgren
- Department of Microbiology and Immunology, Faculty of Medicine and Health, Örebro University, 70182 Örebro, Sweden
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Poroyko VA, Carreras A, Khalyfa A, Khalyfa AA, Leone V, Peris E, Almendros I, Gileles-Hillel A, Qiao Z, Hubert N, Farré R, Chang EB, Gozal D. Chronic Sleep Disruption Alters Gut Microbiota, Induces Systemic and Adipose Tissue Inflammation and Insulin Resistance in Mice. Sci Rep 2016; 6:35405. [PMID: 27739530 PMCID: PMC5064361 DOI: 10.1038/srep35405] [Citation(s) in RCA: 286] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 09/28/2016] [Indexed: 02/08/2023] Open
Abstract
Chronic sleep fragmentation (SF) commonly occurs in human populations, and although it does not involve circadian shifts or sleep deprivation, it markedly alters feeding behaviors ultimately promoting obesity and insulin resistance. These symptoms are known to be related to the host gut microbiota. Mice were exposed to SF for 4 weeks and then allowed to recover for 2 weeks. Taxonomic profiles of fecal microbiota were obtained prospectively, and conventionalization experiments were performed in germ-free mice. Adipose tissue insulin sensitivity and inflammation, as well as circulating measures of inflammation, were assayed. Effect of fecal water on colonic epithelial permeability was also examined. Chronic SF-induced increased food intake and reversible gut microbiota changes characterized by the preferential growth of highly fermentative members of Lachnospiraceae and Ruminococcaceae and a decrease of Lactobacillaceae families. These lead to systemic and visceral white adipose tissue inflammation in addition to altered insulin sensitivity in mice, most likely via enhanced colonic epithelium barrier disruption. Conventionalization of germ-free mice with SF-derived microbiota confirmed these findings. Thus, SF-induced metabolic alterations may be mediated, in part, by concurrent changes in gut microbiota, thereby opening the way for gut microbiome-targeted therapeutics aimed at reducing the major end-organ morbidities of chronic SF.
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Affiliation(s)
- Valeriy A Poroyko
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA.,Department of Medical Oncology, City of Hope, Duarte, CA, 91010, USA
| | - Alba Carreras
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Abdelnaby Khalyfa
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Ahamed A Khalyfa
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Vanessa Leone
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Eduard Peris
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Isaac Almendros
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Alex Gileles-Hillel
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Zhuanhong Qiao
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
| | - Nathaniel Hubert
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Ramon Farré
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, CIBER, Madrid, Spain.,Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain.,Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain
| | - Eugene B Chang
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - David Gozal
- Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL 60637, USA
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Commensal Gram-positive bacteria initiates colitis by inducing monocyte/macrophage mobilization. Mucosal Immunol 2015; 8:152-60. [PMID: 24938744 DOI: 10.1038/mi.2014.53] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/13/2014] [Indexed: 02/07/2023]
Abstract
Breakdown of the intestinal epithelial layer's barrier function results in the inflow of commensal flora and improper immune responses against the commensal flora, leading to inflammatory bowel disease (IBD) development. Using a mouse dextran sodium sulfate (DSS)-induced colitis model, we show here that commensal Gram-positive bacteria trigger the mobilization of inflammatory monocytes and macrophages into the colon. Monocytes/macrophages are major producers of tumor necrosis factor-α (TNF-α), a representative cytokine that aggravates colitis. Notably, pretreating mice with vancomycin, which eliminated Gram-positive bacteria, particularly the Lachnospiraceae family, significantly reduced the severity of the colitis by selectively blocking the recruitment of monocytes/macrophages, but not of other cells. Importantly, vancomycin treatment specifically downregulated the colonic epithelial cell (cEC) expression of C-C chemokine receptor type-2 (CCR2) ligands, which are critical chemokines for monocyte/macrophage mobilization into the inflamed colon. Collectively, these results provide previously undiscovered evidence that Gram-positive commensal bacteria induce colitis by recruiting colitogenic monocytes and macrophages. Our findings may lead to new avenues of treatment for IBD.
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7
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Brosnahan AJ, Jones BJ, Dvorak CM, Brown DR. Morphine attenuates apically-directed cytokine secretion from intestinal epithelial cells in response to enteric pathogens. Pathogens 2014; 3:249-57. [PMID: 25437799 PMCID: PMC4243445 DOI: 10.3390/pathogens3020249] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/17/2014] [Accepted: 03/20/2014] [Indexed: 01/19/2023] Open
Abstract
Epithelial cells represent the first line of host immune defense at mucosal surfaces. Although opioids appear to increase host susceptibility to infection, no studies have examined opioid effects on epithelial immune functions. We tested the hypothesis that morphine alters vectorial cytokine secretion from intestinal epithelial cell (IPEC-J2) monolayers in response to enteropathogens. Both entero-adherent Escherichia coli O157:H7 and entero-invasive Salmonella enterica serovar Typhimurium increased apically-directed IL-6 secretion and bi-directional IL-8 secretion from epithelial monolayers, but only IL-6 secretion evoked by E. coli was reduced by morphine acting through a naloxone-sensitive mechanism. Moreover, the respective type 4 and 5 Toll-like receptor agonists, lipopolysaccharide and flagellin, increased IL-8 secretion from monolayers, which was also attenuated by morphine pretreatment. These results suggest that morphine decreases cytokine secretion and potentially phagocyte migration and activation directed towards the mucosal surface; actions that could increase host susceptibility to some enteric infections.
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Affiliation(s)
- Amanda J Brosnahan
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, 1988 Fitch Avenue, Saint Paul, MN 55108-6010, USA.
| | - Bryan J Jones
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, 1988 Fitch Avenue, Saint Paul, MN 55108-6010, USA.
| | - Cheryl M Dvorak
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, 1988 Fitch Avenue, Saint Paul, MN 55108-6010, USA.
| | - David R Brown
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, 1988 Fitch Avenue, Saint Paul, MN 55108-6010, USA.
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Patten DA, Leivers S, Chadha MJ, Maqsood M, Humphreys PN, Laws AP, Collett A. The structure and immunomodulatory activity on intestinal epithelial cells of the EPSs isolated from Lactobacillus helveticus sp. Rosyjski and Lactobacillus acidophilus sp. 5e2. Carbohydr Res 2013; 384:119-27. [PMID: 24394883 DOI: 10.1016/j.carres.2013.12.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 12/04/2013] [Accepted: 12/06/2013] [Indexed: 11/17/2022]
Abstract
The Lactic acid bacteria (LAB) Lactobacillus acidophilus sp. 5e2 and Lactobacillus helveticus sp. Rosyjski both secrete exopolysaccharides (EPSs) into their surrounding environments during growth. A number of EPSs have previously been shown to exhibit immunomodulatory activity with professional immune cells, such as macrophages, but only limited studies have been reported of their interaction with intestinal epithelial cells. An investigation of the immunomodulatory potential of pure EPSs, isolated from cultures of Lactobacillus acidophilus sp. 5e2 and Lactobacillus helveticus sp. Rosyjski, with the HT29-19A intestinal epithelial cell line are reported here. For the first time the structure of the EPS from Lactobacillus helveticus sp. Rosyjski which is a hetropolysaccharide with a branched pentasaccharide repeat unit containing d-glucose, d-galactose and N-acetyl-d-mannosamine is described. In response to exposure to lactobacilli EPSs HT29-19A cells produce significantly increased levels of the proinflammatory cytokine IL-8. Additionally, the EPSs differentially modulate the mRNA expression of Toll-like receptors. Finally, the pre-treatment of HT29-19A cells with the EPSs sensitises the cells to subsequent challenge with bacterial antigens. The results reported here suggest that EPSs could potentially play a role in intestinal homeostasis via a specific interaction with intestinal epithelial cells.
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Affiliation(s)
- Daniel A Patten
- Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH, UK
| | - Shaun Leivers
- Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH, UK
| | - Marcus J Chadha
- Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH, UK
| | - Mohammed Maqsood
- Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH, UK
| | - Paul N Humphreys
- Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH, UK
| | - Andrew P Laws
- Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH, UK.
| | - Andrew Collett
- Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH, UK.
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An overview on the field of micro- and nanotechnologies for synthetic Peptide-based vaccines. JOURNAL OF DRUG DELIVERY 2011; 2011:181646. [PMID: 21773041 PMCID: PMC3134826 DOI: 10.1155/2011/181646] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 04/05/2011] [Indexed: 11/17/2022]
Abstract
The development of synthetic peptide-based vaccines has many advantages in comparison with vaccines based on live attenuated organisms, inactivated or killed organism, or toxins. Peptide-based vaccines cannot revert to a virulent form, allow a better conservation, and are produced more easily and safely. However, they generate a weaker immune response than other vaccines, and the inclusion of adjuvants and/or the use of vaccine delivery systems is almost always needed. Among vaccine delivery systems, micro- and nanoparticulated ones are attractive, because their particulate nature can increase cross-presentation of the peptide. In addition, they can be passively or actively targeted to antigen presenting cells. Furthermore, particulate adjuvants are able to directly activate innate immune system in vivo. Here, we summarize micro- and nanoparticulated vaccine delivery systems used in the field of synthetic peptide-based vaccines as well as strategies to increase their immunogenicity.
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