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Fish & Shellfish Immunology Dec 2020In echinoderms, the immune system plays a relevant role in defense against infection by pathogens. Particularly, in sea urchins, the immune system has been shown to be...
In echinoderms, the immune system plays a relevant role in defense against infection by pathogens. Particularly, in sea urchins, the immune system has been shown to be complex, especially in terms of the variety of immune genes and molecules described. A key component of the response to external pathogens are the Toll-like receptors (TLRs), which are a well-characterized class of pattern recognition receptors (PRRs) that participate in the recognition of pathogen-associated molecular patterns (PAMPs). Despite the fact that TLRs have been described in several sea urchin species, for the red sea urchin (Loxechinus albus), which is one of the most important sea urchins across the world in terms of fisheries, limited information on the TLR-mediated immune response exists. In the present study, for the first time, we evaluated the effect of thermal stress, LPS and poly I:C treatment on the coelomocyte immune response of Loxechinus albus to determine how these factors modulate TLR and strongylocin (antimicrobial peptides of echinoderms) responses. We show that the tlr3-like, tlr4-like, tlr6-like and tlr8-like transcripts are modulated by poly I:C, while LPS only modulates the tlr4-like response; there was no effect of temperature on TLR expression, as evaluated by RT-qPCR. Additionally, we showed that strongylocin-1 and strongylocin-2 are modulated in response to simulated viral infection with poly I:C, providing the first evidence of strongylocin expression in L. albus. Finally, we determined that temperature and LPS modify the viability of coelomocytes, while poly I:C treatment did not affect the viability of these cells. This study contributes to the knowledge of immune responses in sea urchins to improve the understanding of the role of TLRs and strongylocins in echinoderms.
Topics: Animals; Immunity; Lipopolysaccharides; Poly I-C; Sea Urchins; Temperature
PubMed: 32971271
DOI: 10.1016/j.fsi.2020.09.028 -
Fish & Shellfish Immunology Mar 2018This study was aimed at investigating the cellular responses of Penaeus monodon haemocytes to poly I:C stimulation using flow cytometric assay. Total haemocyte count...
This study was aimed at investigating the cellular responses of Penaeus monodon haemocytes to poly I:C stimulation using flow cytometric assay. Total haemocyte count (THC), percentages of different haemocyte subpopulations [hyaline cells (HC), semigranular cells (SGC) and granular cells (GC)], non-specific esterase activity (EA), total reactive oxygen species/reactive nitrogen species (ROS/RNS) production, nitric oxide (NO) production, apoptotic haemocyte ratio and plasmic phenoloxidase (PO) activity were determined in poly I:C-injected shrimp. Results showed that poly I:C at a low dose (5 μg shrimp) caused obvious increases in THC, GC proportion, ROS/RNS production and NO production, but had no significant effect on EA, apoptosis and PO activity. In the early stage of poly I:C injection at a high dose (20 μg shrimp), THC and GC proportion improvements could also be observed, suggesting that GC might be induced to release from hemocytopoietic or other tissues to participate in immune response, and this subpopulation might be the main cell type involved in the cellular defence against virus. In the later period, proportions of both GC and SGC reduced paralleled by THC reduction, indicating that depletion of GC and SGC was mainly contributed to the reduced count of circulating haemocyte. Obvious increases in ROS/RNS production and NO production were induced in haemocyte of shrimp under a high dose of poly I:C stimulation, but only slight rise of EA and suppression of PO activity could be observed in poly I:C-stimulated shrimp, suggesting that ROS/RNS-dependent system was vital in the immune defence of shrimp against virus. On the other hand, increase of apoptotic haemocyte ratio and THC reduction were presented after the drastic increases of ROS/RNS and NO productions, implying that the stimulated ROS/RNS might be excess and harmful, and was the major factor for the haemocyte apoptosis and depletion. THC recovered after 48 h injection, while haemocyte apoptosis also returned to the control level, suggesting that apoptosis might be contributed to eliminate damaged, weak or infected haemocytes to renew the circulating haemocytes, and it could be considered as an important defending strategy against virus.
Topics: Animals; Flow Cytometry; Hemocytes; Penaeidae; Poly I-C
PubMed: 29288812
DOI: 10.1016/j.fsi.2017.12.045 -
International Journal of Pharmaceutics Aug 2018In this study, we aimed to investigate the immunogenicity of cationic liposomes loaded with diphtheria toxoid (DT) and poly(I:C) after hollow microneedle-mediated...
In this study, we aimed to investigate the immunogenicity of cationic liposomes loaded with diphtheria toxoid (DT) and poly(I:C) after hollow microneedle-mediated intradermal vaccination in mice. The following liposomal formulations were studied: DT loaded liposomes, a mixture of free DT and poly(I:C)-loaded liposomes, a mixture of DT-loaded liposomes and free poly(I:C), and liposomal formulations with DT and poly(I:C) either individually or co-encapsulated in the liposomes. Reference groups were DT solution adjuvanted with or without poly(I:C) (DT/poly(I:C)). The liposomal formulations were characterized in terms of particle size, zeta potential, loading and release of DT and poly(I:C). After intradermal injection of BALB/c mice with the formulations through a hollow microneedle, the immunogenicity was assessed by DT-specific ELISAs. All formulations induced similar total IgG and IgG1 titers. However, all the liposomal groups containing both DT and poly(I:C) showed enhanced IgG2a titers compared to DT/poly(I:C) solution, indicating that the immune response was skewed towards a Th1 direction. This enhancement was similar for all liposomal groups that contain both DT and poly(I:C) in the formulations. Our results reveal that a mixture of DT encapsulated liposomes and poly(I:C) encapsulated liposomes have a similar effect on the antibody responses as DT and poly(I:C) co-encapsulated liposomes. These findings may have implications for future design of liposomal vaccine delivery systems.
Topics: Adjuvants, Immunologic; Animals; Antibody Formation; Cations; Diphtheria Toxoid; Drug Delivery Systems; Drug Liberation; Enzyme-Linked Immunosorbent Assay; Female; Immunoglobulin G; Injections, Intradermal; Liposomes; Mice; Mice, Inbred BALB C; Needles; Particle Size; Poly I-C; Vaccination
PubMed: 29870743
DOI: 10.1016/j.ijpharm.2018.06.001 -
International Journal of Pharmaceutics Jan 2009Microparticles from poly(D,L-lactic-co-glycolic acid) [PLGA] are of steadily rising interest for the delivery of antigens to immune cells and the induction of a...
Microparticles from poly(D,L-lactic-co-glycolic acid) [PLGA] are of steadily rising interest for the delivery of antigens to immune cells and the induction of a long-lasting immune response for vaccination or immunological tumor therapy. However, if the desired vaccine contains only weak antigens and fails to activate the antigen presenting cells (APC), the opposite effect, i.e., the induction of immunotolerance may be observed. Therefore, it was the aim of this study to show the ability of protein loaded PLGA microparticles to additionally carry a specific, surface-coated maturation signal to human dendritic cells (DC), i.e., the most potent APC. Polyinosine-polycytidylic acid [poly(I:C)], a ligand of Toll-like receptor (TLR) 3, was efficiently bound either in a single layer or a multilayer attempt to the surface of diethylaminoethyl dextran modified PLGA microparticles. These particles were effectively phagocytized by DC ex vivo and induced a maturation similar to that achieved with a cytokine cocktail or higher concentrations of soluble poly(I:C). In conclusion, the concept of surface coating of biodegradable microparticles with selected TLR ligands might successfully be used in DC-based cell therapies for cancer or in vaccination trials to induce DC maturation and specifically amplify the immunological response to encapsulated antigens.
Topics: Cells, Cultured; DEAE-Dextran; Dendritic Cells; Humans; Lactic Acid; Ligands; Microspheres; Phagocytosis; Poly I-C; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Toll-Like Receptor 3
PubMed: 18812217
DOI: 10.1016/j.ijpharm.2008.08.039 -
Journal of Controlled Release :... Apr 2012By expressing an array of pattern recognition receptors (PRRs), fibroblasts play an important role in stimulating and modulating the response of the innate immune...
By expressing an array of pattern recognition receptors (PRRs), fibroblasts play an important role in stimulating and modulating the response of the innate immune system. The TLR3 ligand polyriboinosinic acid-polyribocytidylic acid, poly(I:C), a mimic of viral dsRNA, is a vaccine adjuvant candidate to activate professional antigen presenting cells (APCs). However, owing to its ligation with extracellular TLR3 on fibroblasts, subcutaneously administered poly(I:C) bears danger towards autoimmunity. It is thus in the interest of its clinical safety to deliver poly(I:C) in such a way that its activation of professional APCs is as efficacious as possible, whereas its interference with non-immune cells such as fibroblasts is controlled or even avoided. Complementary to our previous work with monocyte-derived dendritic cells (MoDCs), here we sought to control the delivery of poly(I:C) surface-assembled on microspheres to human foreskin fibroblasts (HFFs). Negatively charged polystyrene (PS) microspheres were equipped with a poly(ethylene glycol) (PEG) corona through electrostatically driven coatings with a series of polycationic poly(L-lysine)-graft-poly(ethylene glycol) copolymers, PLL-g-PEG, of varying grafting ratios g from 2.2 up to 22.7. Stable surface assembly of poly(I:C) was achieved by incubation of polymer-coated microspheres with aqueous poly(I:C) solutions. Notably, recognition of both surface-assembled and free poly(I:C) by extracellular TLR3 on HFFs halted their phagocytic activity. Ligation of surface-assembled poly(I:C) with extracellular TLR3 on HFFs could be controlled by tuning the grafting ratio g and thus the chain density of the PEG corona. When assembled on PLL-5.7-PEG-coated microspheres, poly(I:C) was blocked from triggering class I MHC molecule expression on HFFs. Secretion of interleukin (IL)-6 by HFFs after exposure to surface-assembled poly(I:C) was distinctly lower as compared to free poly(I:C). Overall, surface assembly of poly(I:C) may have potential to contribute to the clinical safety of this vaccine adjuvant candidate.
Topics: Adjuvants, Immunologic; Cell Culture Techniques; Cell Survival; Drug Carriers; Fibroblasts; Flow Cytometry; Foreskin; HeLa Cells; Histocompatibility Antigens Class I; Histocompatibility Antigens Class II; Humans; Immunity, Innate; Magnetic Resonance Spectroscopy; Male; Microspheres; Phagocytosis; Poly I-C; Polyethylene Glycols; Polylysine; Toll-Like Receptor 3
PubMed: 22349184
DOI: 10.1016/j.jconrel.2012.02.002 -
Infection and Immunity Oct 1974Liposomes were prepared with phospholipids (sphingomyelin, lecithin, and phosphatidylethanolamine) in combination with cholesterol and charged lipids (dicetyl phosphate...
Liposomes were prepared with phospholipids (sphingomyelin, lecithin, and phosphatidylethanolamine) in combination with cholesterol and charged lipids (dicetyl phosphate and stearylamine) and contained either poly(I):poly(C) or poly(I). Neutral and positively charged liposomes attached much better to L-929 cells in tissue culture than did negatively charged particles. Liposomes were toxic to L cells at relatively low concentrations, making the determination of antiviral activity induced by particles containing poly(I):poly(C) difficult to measure by the plaque reduction assay. When injected into mice, all of the liposomes containing poly(I):poly(C), except phosphatidylethanolamine liposomes, greatly potentiated and extended the serum interferon response of poly(I):poly(C). Lecithin and sphingomyelin liposomes given intravenously were ten times more effective than free poly(I):poly(C) in stimulating production of serum interferon. Sphingomyelin liposomes containing [(14)C]poly(I):poly(C) were 88% cleared from the bloodstream of mice by 3 min after intravenous injection. Most of the radioactivity (70%) was captured by the liver and remained there for at least 4 h. By 2 h, 7% of the radioactivity could be found in the spleen. Five percent of the radioactivity was found in the lungs at 30 min, with decreasing amounts thereafter. Small amounts of radioactivity were found in the muscle and kidneys. The spleen was shown to contain appreciable levels of interferon at 4 h, and low levels were found in the liver. Radioactivity accumulated slowly in the liver following an intraperitoneal injection of sphingomyelin liposomes containing [(14)C]poly(I):poly(C). By 4 h, 26% of the dose was recovered from the liver and 4.9% from the spleen, with small amounts in the lung, kidney, and omentum.
Topics: Animals; Autoradiography; Biological Availability; Carbon Radioisotopes; Female; Injections, Intravenous; Interferons; L Cells; Liposomes; Liver; Lung; Mice; Pharmaceutic Aids; Phospholipids; Poly I-C; Spleen; Viral Interference
PubMed: 4426708
DOI: 10.1128/iai.10.4.783-792.1974 -
Molecular Neurobiology Jan 2016The release of inflammatory mediators following cortical spreading depression (CSD) is suggested to play a role in pathophysiology of CSD-related neurological disorders....
The release of inflammatory mediators following cortical spreading depression (CSD) is suggested to play a role in pathophysiology of CSD-related neurological disorders. Toll-like receptors (TLR) are master regulators of innate immune function and involved in the activation of inflammatory responses in the brain. TLR3 agonist poly I:C exerts anti-inflammatory effect and prevents cell injury in the brain. The aim of the present study was to examine the effect of systemic administration of poly I:C on the release of cytokines (TNF-α, IFN-γ, IL-4, TGF-β1, and GM-CSF) in the brain and spleen, splenic lymphocyte proliferation, expression of GAD65, GABAAα, GABAAβ as well as Hsp70, and production of dark neurons after induction of repetitive CSD in juvenile rats. Poly I:C significantly attenuated CSD-induced production of TNF-α and IFN-γ in the brain as well as TNF-α and IL-4 in the spleen. Poly I:C did not affect enhancement of splenic lymphocyte proliferation after CSD. Administration of poly I:C increased expression of GABAAα, GABAAβ as well as Hsp70 and decreased expression of GAD65 in the entorhinal cortex compared to CSD-treated tissues. In addition, poly I:C significantly prevented production of CSD-induced dark neurons. The data indicate neuroprotective and anti-inflammatory effects of TLR3 activation on CSD-induced neuroinflammation. Targeting TLR3 may provide a novel strategy for developing new treatments for CSD-related neurological disorders.
Topics: Animals; Cerebral Cortex; Cortical Spreading Depression; Disease Models, Animal; Granulocyte-Macrophage Colony-Stimulating Factor; Male; Neurons; Poly I-C; Rats, Wistar; Toll-Like Receptor 3; Tumor Necrosis Factor-alpha
PubMed: 25416860
DOI: 10.1007/s12035-014-8995-z -
Fish & Shellfish Immunology Apr 2019The yellow catfish (Pelteobagrus fulvidraco) is an economically important fish in China, but Edwardsiella ictaluri, an intracellular pathogenic bacterium, causes great...
The yellow catfish (Pelteobagrus fulvidraco) is an economically important fish in China, but Edwardsiella ictaluri, an intracellular pathogenic bacterium, causes great losses to the culture industry. Currently, vaccination is the most promising strategy to combat the infectious diseases, while adjuvant can provide effective assistant for vaccines to enhance immune responses. In the present study, inactivated E. ictaluri vaccine was prepared, then Astragalus polysaccharides (APS), chitosan and poly(I:C) were employed as adjuvants to evaluate the effect on boosting immune responses and protecting yellow catfish against E. ictaluri. The survival rate was obviously improved after vaccination with APS, chitosan or poly(I:C) respectively, in addition, these three adjuvants could clearly protect the target tissue (intestine) by pathological sections in infectious experiments. In sera, total protein levels increased throughout the immunization stages, total superoxide dismutase levels continued to raise after vaccination, and lysozyme activity levels improved at different periods, examining by the commercial kits. Moreover, checking by real time quantitative RT-PCR assays, in both spleen and head kidney tissues which were the major immune organs, mRNA expressions of inflammatory cytokine IL-1β increased in the early stage of immunity, typical Th1 immune response cytokines IL-2 and IFN-γ2 rose up in the whole immune period, and IgM significantly enhanced in the adjuvant supplementation groups. The results demonstrated the good efficiency of APS, chitosan or poly(I:C) as adjuvant, and provided more options for the fish adjuvants.
Topics: Adjuvants, Immunologic; Animals; Astragalus Plant; Bacterial Vaccines; Catfishes; Chitosan; Edwardsiella ictaluri; Enterobacteriaceae Infections; Fish Diseases; Poly I-C; Polysaccharides; Vaccine Potency; Vaccines, Inactivated
PubMed: 30690155
DOI: 10.1016/j.fsi.2019.01.033 -
Journal of Neuroinflammation Jan 2020Individuals with impaired immunity are more susceptible to infections than immunocompetent subjects. No vaccines are currently available to induce protection against E....
Pre-treatment with the viral Toll-like receptor 3 agonist poly(I:C) modulates innate immunity and protects neutropenic mice infected intracerebrally with Escherichia coli.
BACKGROUND
Individuals with impaired immunity are more susceptible to infections than immunocompetent subjects. No vaccines are currently available to induce protection against E. coli meningoencephalitis. This study evaluated the potential of poly(I:C) pre-treatment to induce trained immunity. Poly(I:C) was administered as a non-specific stimulus of innate immune responses to protect immunocompetent and neutropenic wild-type mice from a subsequent challenge by the intracranial injection of E. coli K1.
METHODS
Three days prior to infection, mice received an intraperitoneal injection of poly(I:C) or vehicle. Kaplan-Meier survival curves were analyzed. In short-term experiments, bacterial titers and the inflammatory response were characterized in the blood, cerebellum, and spleen homogenates. NK cell subpopulations in the brain and spleen were analyzed by flow cytometry. Numbers of microglia and activation scores were evaluated by histopathology.
RESULTS
Pre-treatment with 200 μg poly(I:C) increased survival time, reduced mortality, and enhanced bacterial clearance in the blood, cerebellum, and spleen at early infection in neutropenic mice. Poly(I:C)-mediated protection correlated with an augmented number of NK cells (CD45NK1.1CD3) and Iba-1 microglial cells and a higher production of IFN-γ in the brain. In the spleen, levels of CCL5/RANTES and IFN-γ were increased and sustained in surviving poly(I:C)-treated animals for 14 days after infection. In immunocompetent animals, survival time was not significantly prolonged in poly(I:C)-treated animals although poly(I:C) priming reduced brain bacterial concentrations compared with vehicle-injected animals at early infection.
CONCLUSIONS
Pre-treatment with the viral TLR3 agonist poly(I:C) modulated innate immune responses and strengthened the resistance of neutropenic mice against E. coli K1 meningoencephalitis.
Topics: Animals; Immunity, Innate; Immunocompromised Host; Male; Meningitis, Escherichia coli; Mice; Mice, Inbred C57BL; Neutropenia; Poly I-C; Toll-Like Receptor 3
PubMed: 31952519
DOI: 10.1186/s12974-020-1700-4 -
Acta Biomaterialia Dec 2017The selective activation of the immune system is a concurrent problem in the treatment of persistent diseases like viral infections (e.g. hepatitis). For the delivery of...
UNLABELLED
The selective activation of the immune system is a concurrent problem in the treatment of persistent diseases like viral infections (e.g. hepatitis). For the delivery of the toll-like receptor ligand poly(I:C), an immunostimulatory action was discovered earlier by hydrodynamic injection. However, this technique is not clinically transferable to human patients. A modular system where the immunoactive toll-like-receptor ligand 3 (TLR-3) poly(I:C) was incorporated into calcium phosphate nanoparticles was developed. The nanoparticles had a hydrodynamic diameter of 275nm and a zeta potential of +20mV, measured by dynamic light scattering. The diameter of the solid core was 120nm by scanning electron microscopy. In vitro, the nanoparticle uptake was investigated after 1 and 24h of incubation of THP-1 cells (macrophages) with nanoparticles by fluorescence microscopy. After intravenous injection into BALB/c and C57BL/6J mice, respectively, the in vivo uptake was especially prominent in lung and liver, 1 and 3h after the injection. Pronounced immunostimulatory effects of the nanoparticles were found in vitro with primary liver cells, i.e. Kupffer cells (KC) and liver sinusoidal endothelial cells (LSEC) from wild-type C57BL/6J mice. Thus, they represent a suitable alternative to hydrodynamic injection treatments for future vaccination concepts.
STATEMENT OF SIGNIFICANCE
The selective activation of the immune system is a concurrent problem in the treatment of persistent diseases like viral infections (e.g. hepatitis). For the delivery of the toll-like receptor ligand poly(I:C), an immunostimulatory action has been discovered earlier by hydrodynamic injection. However, this technique is not clinically transferable to human patients. We have developed a modular system where poly(I:C) was incorporated into calcium phosphate nanoparticles. The uptake into relevant liver cells was studied both in vitro and in vivo. After intravenous injection into mice, the in vivo uptake was especially prominent in lung and liver, 1 and 3h after the injection. The corresponding strong immune reaction proves their high potential to turn up the immune system, e.g. against viral infections, without adverse side reactions.
Topics: Animals; Calcium Phosphates; Drug Delivery Systems; Humans; Immunization; Mice; Mice, Inbred BALB C; Nanoparticles; Poly I-C; THP-1 Cells; Toll-Like Receptor 3
PubMed: 28963016
DOI: 10.1016/j.actbio.2017.09.037