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1.
Nano Lett ; 23(11): 5035-5041, 2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37235534

RESUMO

Highly anisotropic materials show great promise for spatial control and the manipulation of polaritons. In-plane hyperbolic phonon polaritons (HPhPs) supported by α-phase molybdenum trioxide (MoO3) allow for wave propagation with a high directionality due to the hyperbola-shaped isofrequency contour (IFC). However, the IFC prohibits propagations along the [001] axis, hindering information or energy flow. Here, we illustrate a novel approach to manipulating the HPhP propagation direction. We experimentally demonstrate that geometrical confinement in the [100] axis can guide HPhPs along the forbidden direction with phase velocity becoming negative. We further developed an analytical model to provide insights into this transition. Moreover, as the guided HPhPs are formed in-plane, modal profiles were directly imaged to further expand our understanding of the formation of HPhPs. Our work reveals a possibility for manipulating HPhPs and paves the way for promising applications in metamaterials, nanophotonics, and quantum optics based on natural van der Waals materials.

2.
Nanotechnology ; 34(2)2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36167030

RESUMO

High-pressure-torsion (HPT) processing introduces a large density of dislocations that form sub-grain boundaries within the refined nano-scale structure, leading to changes in precipitate morphology compared to hot-rolled maraging steels. The impact of such nanostructuring on the deformation and fracture micro-mechanisms is being reported for the first time usingin situcharacterization techniques along with transmission electron microscopy and atom probe tomography analysis, in this study. Digital image correlation has been used to quantify the full field strain maps in regions of severe strain localization as well as to determine the fracture toughness through critical crack tip opening displacements. It is seen that the phenomenon of planar slip leads to strain softening under uniaxial deformation and to crack branching under a triaxial stress state in hot rolled maraging steels. On the other hand, nano-structuring after HPT processing creates a large number of high angle grain boundaries as dislocation barriers, leading to strain hardening under uniaxial tension and nearly straight crack path with catastrophic fracture under triaxial stress state. Upon overaging, the hot-rolled sample shows signature of transformation induced plasticity under uniaxial tension, which is absent in the HPT processed overaged samples, owing to the finer reverted austenite grains containing higher Ni concentration in the latter. In the overaged fracture test samples of both the hot-rolled and HPT conditions, crack tips show a signature of strain induced transformation of the reverted austenite to martensite, due to the accompanying severe strain gradients. This leads to a higher fracture toughness even while achieving high strengths in the overaged conditions of the nanocrystalline HPT overaged samples. The results presented here will aid in design of suitable heat treatment or microstructure engineering of interface dominated nano-scale maraging steels with improved damage tolerance.

3.
Infect Immun ; 89(11): e0016521, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34310889

RESUMO

Preerythrocytic vaccines prevent malaria by targeting parasites in the clinically silent sporozoite and liver stages and preventing progression to the virulent blood stages. The leading preerythrocytic vaccine, RTS,S/AS01E (Mosquirix), entered implementation programs in 2019 and targets the major sporozoite surface antigen, circumsporozoite protein (CSP). However, in phase III clinical trials, RTS,S conferred partial protection with limited durability, indicating a need to improve CSP-based vaccination. Previously, we identified highly expressed liver-stage proteins that could potentially be used in combination with CSP; they are referred to as preerythrocytic vaccine antigens (PEVAs). Here, we developed heterologous prime-boost CSP vaccination models to confer partial sterilizing immunity against Plasmodium yoelii (protein prime-adenovirus 5 [Ad5] boost) and Plasmodium berghei (DNA prime-Ad5 boost) in mice. When combined as individual antigens with P. yoelii CSP (PyCSP), three of eight P. yoelii PEVAs significantly enhanced sterile protection against sporozoite challenge, compared to PyCSP alone. Similar results were obtained when three P. berghei PEVAs and P. berghei CSP were combined in a single vaccine regimen. In general, PyCSP antibody responses were similar after CSP alone versus CSP plus PEVA vaccinations. Both P. yoelii and P. berghei CSP plus PEVA combination vaccines induced robust CD8+ T cell responses, including signature gamma interferon (IFN-γ) increases. In the P. berghei model system, IFN-γ responses were significantly higher in hepatic versus splenic CD8+ T cells. The addition of novel antigens may enhance the degree and duration of sterile protective immunity conferred by a human vaccine such as RTS,S.


Assuntos
Antígenos de Protozoários/imunologia , Vacinas Antimaláricas/imunologia , Proteínas de Protozoários/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Interferon gama/biossíntese , Ativação Linfocitária , Malária/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C , Vacinação
4.
Mediators Inflamm ; 2020: 7461742, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32684836

RESUMO

The immunopathology of chlamydial diseases is exacerbated by a broad-spectrum of inflammatory mediators, which we reported are inhibited by IL-10 in macrophages. However, the chlamydial protein moiety that induces the inflammatory mediators and the mechanisms by which IL-10 inhibits them are unknown. We hypothesized that Chlamydia major outer membrane protein (MOMP) mediates its disease pathogenesis, and the suppressor of cytokine signaling (SOCS)1 and SOCS3 proteins are mediators of the IL-10 inhibitory actions. Our hypothesis was tested by exposing mouse J774 macrophages to chlamydial stimulants (live Chlamydia muridarum and MOMP) with and without IL-10. MOMP significantly induced several inflammatory mediators (IL-6, IL-12p40, CCL5, CXCL10), which were dose-dependently inhibited by IL-10. Chlamydial stimulants induced the mRNA gene transcripts and protein expression of SOCS1 and SOCS3, with more SOCS3 expression. Notably, IL-10 reciprocally regulated their expression by reducing SOCS1 and increasing SOCS3. Specific inhibitions of MAPK pathways revealed that p38, JNK, and MEK1/2 are required for inducing inflammatory mediators as well as SOCS1 and SOCS3. Chlamydial stimulants triggered an M1 pro-inflammatory phenotype evidently by an enhanced nos2 (M1 marker) expression, which was skewed by IL-10 towards a more M2 anti-inflammatory phenotype by the increased expression of mrc1 and arg1 (M2 markers) and the reduced SOCS1/SOCS3 ratios. Neutralization of endogenously produced IL-10 augmented the secretion of inflammatory mediators, reduced SOCS3 expression, and skewed the chlamydial M1 to an M2 phenotype. Inhibition of proteasome degradation increased TNF but decreased IL-10, CCL5, and CXCL10 secretion by suppressing SOCS1 and SOCS3 expressions and dysregulating their STAT1 and STAT3 transcription factors. Our data show that SOCS1 and SOCS3 are regulators of IL-10 inhibitory actions, and underscore SOCS proteins as therapeutic targets for IL-10 control of inflammation for Chlamydia and other bacterial inflammatory diseases.


Assuntos
Proteínas da Membrana Bacteriana Externa/toxicidade , Chlamydia muridarum/patogenicidade , Inflamação/metabolismo , Interleucina-10/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Proteína 1 Supressora da Sinalização de Citocina/metabolismo , Proteína 3 Supressora da Sinalização de Citocinas/metabolismo , Animais , Linhagem Celular , Citometria de Fluxo , Camundongos , Microscopia de Fluorescência , Proteína 1 Supressora da Sinalização de Citocina/genética , Proteína 3 Supressora da Sinalização de Citocinas/genética
5.
Nanomedicine ; 29: 102257, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32610072

RESUMO

Vaccine developmental strategies are utilizing antigens encapsulated in biodegradable polymeric nanoparticles. Here, we developed a Chlamydia nanovaccine (PLGA-rMOMP) by encapsulating its recombinant major outer membrane protein (rMOMP) in the extended-releasing and self-adjuvanting PLGA [poly (D, L-lactide-co-glycolide) (85:15)] nanoparticles. PLGA-rMOMP was small (nanometer size), round and smooth, thermally stable, and exhibited a sustained release of rMOMP. Stimulation of mouse primary dendritic cells (DCs) with PLGA-rMOMP augmented endosome processing, induced Th1 cytokines (IL-6 and IL-12p40), and expression of MHC-II and co-stimulatory (CD40, CD80, and CD86) molecules. BALB/c mice immunized with PLGA-rMOMP produced enhanced CD4+ T-cells-derived memory (CD44high CD62Lhigh), and effector (CD44high CD62Llow) phenotypes and functional antigen-specific serum IgG antibodies. In vivo biodistribution of PLGA-rMOMP revealed its localization within lymph nodes, suggesting migration from the injection site via DCs. Our data provide evidence that the PLGA (85:15) nanovaccine activates DCs and augments Chlamydia-specific rMOMP adaptive immune responses that are worthy of efficacy testing.


Assuntos
Imunidade Adaptativa/genética , Proteínas da Membrana Bacteriana Externa/genética , Nanopartículas/química , Vacinas/imunologia , Imunidade Adaptativa/imunologia , Animais , Proteínas da Membrana Bacteriana Externa/imunologia , Antígenos CD4/química , Antígenos CD4/imunologia , Chlamydia/genética , Chlamydia/imunologia , Chlamydia/patogenicidade , Células Dendríticas/imunologia , Antígenos de Histocompatibilidade Classe II/genética , Humanos , Receptores de Hialuronatos/química , Receptores de Hialuronatos/imunologia , Subunidade p40 da Interleucina-12/genética , Subunidade p40 da Interleucina-12/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Selectina L/química , Selectina L/imunologia , Camundongos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/imunologia , Linfócitos T/imunologia , Vacinas/genética
6.
Int J Mol Sci ; 18(4)2017 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-28387714

RESUMO

Tissue engineered skin substitutes for wound healing have evolved tremendously over the last couple of years. New advances have been made toward developing skin substitutes made up of artificial and natural materials. Engineered skin substitutes are developed from acellular materials or can be synthesized from autologous, allograft, xenogenic, or synthetic sources. Each of these engineered skin substitutes has their advantages and disadvantages. However, to this date, a complete functional skin substitute is not available, and research is continuing to develop a competent full thickness skin substitute product that can vascularize rapidly. There is also a need to redesign the currently available substitutes to make them user friendly, commercially affordable, and viable with longer shelf life. The present review focuses on providing an overview of advances in the field of tissue engineered skin substitute development, the availability of various types, and their application.


Assuntos
Fenômenos Fisiológicos da Pele , Engenharia Tecidual/métodos , Cicatrização , Materiais Biocompatíveis , Humanos , Regeneração , Transplante de Pele , Pele Artificial
7.
Nanomedicine ; 12(8): 2299-2310, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27381068

RESUMO

Respiratory syncytial virus (RSV) causes severe pneumonia and bronchiolitis in infants, children and older adults. The use of metallic nanoparticles as potential therapeutics is being explored against respiratory viruses like Influenza, Parainfluenza and Adenovirus. In this study, we showed that gold nanorods (GNRs) inhibit RSV in HEp-2 cells and BALB/c mice by 82% and 56%, respectively. The RSV inhibition correlated with marked upregulated antiviral genes due to GNR mediated TLR, NOD-like receptor and RIG-I-like receptor signaling pathways. Transmission electron microscopy of lungs showed GNRs in the endocytotic vesicles and histological analyses indicated infiltration by neutrophils, eosinophils and monocytes correlating with clearance of RSV. In addition, production of cytokines and chemokines in the lungs indicates recruitment of immune cells to counter RSV replication. To our knowledge, this is the first in vitro and in vivo report that provides possible antiviral mechanisms of GNRs against RSV.


Assuntos
Ouro/farmacologia , Imunidade Inata , Nanotubos , Infecções por Vírus Respiratório Sincicial/tratamento farmacológico , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Animais , Ouro/administração & dosagem , Humanos , Camundongos , Camundongos Endogâmicos NOD
8.
Int J Mol Sci ; 17(12)2016 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-27898014

RESUMO

Over centuries, the field of regenerative skin tissue engineering has had several advancements to facilitate faster wound healing and thereby restoration of skin. Skin tissue regeneration is mainly based on the use of suitable scaffold matrices. There are several scaffold types, such as porous, fibrous, microsphere, hydrogel, composite and acellular, etc., with discrete advantages and disadvantages. These scaffolds are either made up of highly biocompatible natural biomaterials, such as collagen, chitosan, etc., or synthetic materials, such as polycaprolactone (PCL), and poly-ethylene-glycol (PEG), etc. Composite scaffolds, which are a combination of natural or synthetic biomaterials, are highly biocompatible with improved tensile strength for effective skin tissue regeneration. Appropriate knowledge of the properties, advantages and disadvantages of various biomaterials and scaffolds will accelerate the production of suitable scaffolds for skin tissue regeneration applications. At the same time, emphasis on some of the leading challenges in the field of skin tissue engineering, such as cell interaction with scaffolds, faster cellular proliferation/differentiation, and vascularization of engineered tissues, is inevitable. In this review, we discuss various types of scaffolding approaches and biomaterials used in the field of skin tissue engineering and more importantly their future prospects in skin tissue regeneration efforts.


Assuntos
Materiais Biocompatíveis/química , Engenharia Tecidual/métodos , Polímeros/química , Pele , Alicerces Teciduais/química , Cicatrização/fisiologia
9.
Nanomedicine ; 10(6): 1311-21, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24602605

RESUMO

PLA-PEG [poly(lactic acid)-poly (ethylene glycol)], a biodegradable copolymer, is underexploited for vaccine delivery although it exhibits enhanced biocompatibility and slow release immune-potentiating properties. We document here successful encapsulation of M278, a Chlamydia trachomatis MOMP (major outer-membrane protein) peptide, within PLA-PEG nanoparticles by size (~73-100nm), zeta potential (-16 mV), smooth morphology, encapsulation efficiency (~60%), slow release pattern, and non-toxicity to macrophages. Immunization of mice with encapsulated M278 elicited higher M278-specific T-cell cytokines [Th1 (IFN-γ, IL-2), Th17 (IL-17)] and antibodies [Th1 (IgG2a), Th2 (IgG1, IgG2b)] compared to bare M278. Encapsulated-M278 mouse serum inhibited Chlamydia infectivity of macrophages, with a concomitant transcriptional down-regulation of MOMP, its cognate TLR2 and CD80 co-stimulatory molecule. Collectively, encapsulated M278 potentiated crucial adaptive immune responses, which are required by a vaccine candidate for protective immunity against Chlamydia. Our data highlight PLA-PEG's potential for vaccines, which resides in its slow release and potentiating effects to bolster immune responses. FROM THE CLINICAL EDITOR: This study highlights the potential of a PLA-PEG-based nanoparticle formulation containing a major outer membrane protein of chlamydia trachomatis in inducing a sustained enhanced immune response, paving the way to the development of a vaccination strategy against this infection.


Assuntos
Proteínas da Membrana Bacteriana Externa/administração & dosagem , Vacinas Bacterianas/administração & dosagem , Infecções por Chlamydia/prevenção & controle , Chlamydia trachomatis/imunologia , Portadores de Fármacos/química , Lactatos/química , Nanopartículas/química , Polietilenoglicóis/química , Imunidade Adaptativa , Animais , Proteínas da Membrana Bacteriana Externa/imunologia , Vacinas Bacterianas/imunologia , Infecções por Chlamydia/imunologia , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/imunologia
10.
Infect Immun ; 81(6): 1984-9, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23509152

RESUMO

Pfs25 is a leading candidate for a malaria transmission-blocking vaccine whose potential has been demonstrated in a phase 1 trial with recombinant Pfs25 formulated with Montanide ISA51. Because of limited sequence polymorphism, the anti-Pfs25 antibodies induced by this vaccine are likely to have transmission-blocking or -reducing activity against most, if not all, field isolates. To test this hypothesis, we evaluated transmission-blocking activities by membrane feeding assay of anti-Pfs25 plasma from the Pfs25/ISA51 phase 1 trial against Plasmodium falciparum parasites from patients in two different geographical regions of the world, Thailand and Burkina Faso. In parallel, parasite isolates from these patients were sequenced for the Pfs25 gene and genotyped for seven microsatellites. The results indicate that despite different genetic backgrounds among parasite isolates, the Pfs25 sequences are highly conserved, with a single nonsynonymous nucleotide polymorphism detected in 1 of 41 patients in Thailand and Burkina Faso. The anti-Pfs25 immune plasma had significantly higher transmission-reducing activity against parasite isolates from the two geographical regions than the nonimmune controls (P < 0.0001).


Assuntos
Anticorpos Antiprotozoários/imunologia , Vacinas Antimaláricas/imunologia , Malária Falciparum/transmissão , Plasmodium falciparum/genética , Proteínas de Protozoários/imunologia , Animais , Anopheles/parasitologia , Burkina Faso/epidemiologia , Variação Genética , Humanos , Soros Imunes/imunologia , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Repetições de Microssatélites , Plasmodium falciparum/imunologia , Tailândia/epidemiologia
11.
Antimicrob Agents Chemother ; 57(1): 425-35, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23129054

RESUMO

Malaria is a deadly infectious disease in many tropical and subtropical countries. Previous efforts to eradicate malaria have failed, largely due to the emergence of drug-resistant parasites, insecticide-resistant mosquitoes and, in particular, the lack of drugs or vaccines to block parasite transmission. ATP-binding cassette (ABC) transporters are known to play a role in drug transport, metabolism, and resistance in many organisms, including malaria parasites. To investigate whether a Plasmodium falciparum ABC transporter (Pf14_0244 or PfABCG2) modulates parasite susceptibility to chemical compounds or plays a role in drug resistance, we disrupted the gene encoding PfABCG2, screened the recombinant and the wild-type 3D7 parasites against a library containing 2,816 drugs approved for human or animal use, and identified an antihistamine (ketotifen) that became less active against the PfABCG2-disrupted parasite in culture. In addition to some activity against asexual stages and gametocytes, ketotifen was highly potent in blocking oocyst development of P. falciparum and the rodent parasite Plasmodium yoelii in mosquitoes. Tests of structurally related tricyclic compounds identified additional compounds with similar activities in inhibiting transmission. Additionally, ketotifen appeared to have some activity against relapse of Plasmodium cynomolgi infection in rhesus monkeys. Further clinical evaluation of ketotifen and related compounds, including synthetic new derivatives, in blocking malaria transmission may provide new weapons for the current effort of malaria eradication.


Assuntos
Antimaláricos/farmacologia , Cetotifeno/farmacologia , Malária Falciparum/prevenção & controle , Malária/prevenção & controle , Oocistos/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Plasmodium yoelii/efeitos dos fármacos , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Antialérgicos/farmacologia , Transporte Biológico/efeitos dos fármacos , Reposicionamento de Medicamentos , Ensaios de Triagem em Larga Escala , Humanos , Cetotifeno/análogos & derivados , Macaca mulatta , Malária/metabolismo , Malária/parasitologia , Malária/transmissão , Malária Falciparum/metabolismo , Malária Falciparum/parasitologia , Malária Falciparum/transmissão , Camundongos , Oocistos/crescimento & desenvolvimento , Plasmodium cynomolgi/efeitos dos fármacos , Plasmodium cynomolgi/crescimento & desenvolvimento , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium yoelii/crescimento & desenvolvimento , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia
12.
Antiviral Res ; 213: 105589, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37003305

RESUMO

The COVID-19 pandemic spurred the rapid development of a range of therapeutic antibody treatments. As part of the US government's COVID-19 therapeutic response, a research team was assembled to support assay and animal model development to assess activity for therapeutics candidates against SARS-CoV-2. Candidate treatments included monoclonal antibodies, antibody cocktails, and products derived from blood donated by convalescent patients. Sixteen candidate antibody products were obtained directly from manufacturers and evaluated for neutralization activity against the WA-01 isolate of SARS-CoV-2. Products were further tested in the Syrian hamster model using prophylactic (-24 h) or therapeutic (+8 h) treatment approaches relative to intranasal SARS-CoV-2 exposure. In vivo assessments included daily clinical scores and body weights. Viral RNA and viable virus titers were quantified in serum and lung tissue with histopathology performed at 3d and 7d post-virus-exposure. Sham-treated, virus-exposed hamsters showed consistent clinical signs with concomitant weight loss and had detectable viral RNA and viable virus in lung tissue. Histopathologically, interstitial pneumonia with consolidation was present. Therapeutic efficacy was identified in treated hamsters by the absence or diminution of clinical scores, body weight loss, viral loads, and improved semiquantitative lung histopathology scores. This work serves as a model for the rapid, systematic in vitro and in vivo assessment of the efficacy of candidate therapeutics at various stages of clinical development. These efforts provided preclinical efficacy data for therapeutic candidates. Furthermore, these studies were invaluable for the phenotypic characterization of SARS CoV-2 disease in hamsters and of utility to the broader scientific community.


Assuntos
COVID-19 , SARS-CoV-2 , Cricetinae , Animais , Humanos , Mesocricetus , Pandemias , Anticorpos Monoclonais/uso terapêutico , Modelos Animais de Doenças , RNA Viral
13.
Antiviral Res ; 214: 105605, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37068595

RESUMO

This study compared disease progression of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in three different models of golden hamsters: aged (≈60 weeks old) wild-type (WT), young (6 weeks old) WT, and adult (14-22 weeks old) hamsters expressing the human-angiotensin-converting enzyme 2 (hACE2) receptor. After intranasal (IN) exposure to the SARS-CoV-2 Washington isolate (WA01/2020), 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography with computed tomography (18F-FDG PET/CT) was used to monitor disease progression in near real time and animals were euthanized at pre-determined time points to directly compare imaging findings with other disease parameters associated with coronavirus disease 2019 (COVID-19). Consistent with histopathology, 18F-FDG-PET/CT demonstrated that aged WT hamsters exposed to 105 plaque forming units (PFU) developed more severe and protracted pneumonia than young WT hamsters exposed to the same (or lower) dose or hACE2 hamsters exposed to a uniformly lethal dose of virus. Specifically, aged WT hamsters presented with a severe interstitial pneumonia through 8 d post-exposure (PE), while pulmonary regeneration was observed in young WT hamsters at that time. hACE2 hamsters exposed to 100 or 10 PFU virus presented with a minimal to mild hemorrhagic pneumonia but succumbed to SARS-CoV-2-related meningoencephalitis by 6 d PE, suggesting that this model might allow assessment of SARS-CoV-2 infection on the central nervous system (CNS). Our group is the first to use (18F-FDG) PET/CT to differentiate respiratory disease severity ranging from mild to severe in three COVID-19 hamster models. The non-invasive, serial measure of disease progression provided by PET/CT makes it a valuable tool for animal model characterization.


Assuntos
COVID-19 , Pneumonia , Humanos , Animais , Cricetinae , COVID-19/diagnóstico por imagem , SARS-CoV-2 , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Enzima de Conversão de Angiotensina 2 , Tomografia por Emissão de Pósitrons , Mesocricetus , Progressão da Doença
14.
Cell Host Microbe ; 31(1): 97-111.e12, 2023 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-36347257

RESUMO

Humanity has faced three recent outbreaks of novel betacoronaviruses, emphasizing the need to develop approaches that broadly target coronaviruses. Here, we identify 55 monoclonal antibodies from COVID-19 convalescent donors that bind diverse betacoronavirus spike proteins. Most antibodies targeted an S2 epitope that included the K814 residue and were non-neutralizing. However, 11 antibodies targeting the stem helix neutralized betacoronaviruses from different lineages. Eight antibodies in this group, including the six broadest and most potent neutralizers, were encoded by IGHV1-46 and IGKV3-20. Crystal structures of three antibodies of this class at 1.5-1.75-Å resolution revealed a conserved mode of binding. COV89-22 neutralized SARS-CoV-2 variants of concern including Omicron BA.4/5 and limited disease in Syrian hamsters. Collectively, these findings identify a class of IGHV1-46/IGKV3-20 antibodies that broadly neutralize betacoronaviruses by targeting the stem helix but indicate these antibodies constitute a small fraction of the broadly reactive antibody response to betacoronaviruses after SARS-CoV-2 infection.


Assuntos
COVID-19 , SARS-CoV-2 , Animais , Cricetinae , Anticorpos Monoclonais , Surtos de Doenças , Mesocricetus , Anticorpos Antivirais , Anticorpos Neutralizantes , Glicoproteína da Espícula de Coronavírus/genética
15.
J Hosp Leis Sport Tour Educ ; 30: 100360, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34840528

RESUMO

Academic research in tourism and hospitality sector adds value directly to the way the industry grows and develops. Scholars in this area struggle with the pressures to publish in high ranking journals. The present study attempts to help doctoral students and tourism educators in identifying emerging themes in the tourism and hospitality arising out after COVID-19 pandemic. Using bibliometric analysis, five broad areas of emerging research themes are identified. Such research would further help managers, tourism related state administrators, and firm owners to recover from the devastating impact of COVID-19 on the industry across the world.

16.
NPJ Vaccines ; 7(1): 166, 2022 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-36528644

RESUMO

Experimental vaccines for the deadly zoonotic Nipah (NiV), Hendra (HeV), and Ebola (EBOV) viruses have focused on targeting individual viruses, although their geographical and bat reservoir host overlaps warrant creation of multivalent vaccines. Here we explored whether replication-incompetent pseudotyped vesicular stomatitis virus (VSV) virions or NiV-based virus-like particles (VLPs) were suitable multivalent vaccine platforms by co-incorporating multiple surface glycoproteins from NiV, HeV, and EBOV onto these virions. We then enhanced the vaccines' thermotolerance using carbohydrates to enhance applicability in global regions that lack cold-chain infrastructure. Excitingly, in a Syrian hamster model of disease, the VSV multivalent vaccine elicited safe, strong, and protective neutralizing antibody responses against challenge with NiV, HeV, or EBOV. Our study provides proof-of-principle evidence that replication-incompetent multivalent viral particle vaccines are sufficient to provide protection against multiple zoonotic deadly viruses with high pandemic potential.

17.
bioRxiv ; 2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35441178

RESUMO

The potential for future coronavirus outbreaks highlights the need to develop strategies and tools to broadly target this group of pathogens. Here, using an epitope-agnostic approach, we identified six monoclonal antibodies that bound to spike proteins from all seven human-infecting coronaviruses. Epitope mapping revealed that all six antibodies target the conserved fusion peptide region adjacent to the S2' cleavage site. Two antibodies, COV44-62 and COV44-79, broadly neutralize a range of alpha and beta coronaviruses, including SARS-CoV-2 Omicron subvariants BA.1 and BA.2, albeit with lower potency than RBD-specific antibodies. In crystal structures of Fabs COV44-62 and COV44-79 with the SARS-CoV-2 fusion peptide, the fusion peptide epitope adopts a helical structure and includes the arginine at the S2' cleavage site. Importantly, COV44-79 limited disease caused by SARS-CoV-2 in a Syrian hamster model. These findings identify the fusion peptide as the target of the broadest neutralizing antibodies in an epitope-agnostic screen, highlighting this site as a candidate for next-generation coronavirus vaccine development. One-Sentence Summary: Rare monoclonal antibodies from COVID-19 convalescent individuals broadly neutralize coronaviruses by targeting the fusion peptide.

18.
Science ; 377(6607): 728-735, 2022 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-35857439

RESUMO

The potential for future coronavirus outbreaks highlights the need to broadly target this group of pathogens. We used an epitope-agnostic approach to identify six monoclonal antibodies that bind to spike proteins from all seven human-infecting coronaviruses. All six antibodies target the conserved fusion peptide region adjacent to the S2' cleavage site. COV44-62 and COV44-79 broadly neutralize alpha- and betacoronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants BA.2 and BA.4/5, albeit with lower potency than receptor binding domain-specific antibodies. In crystal structures of COV44-62 and COV44-79 antigen-binding fragments with the SARS-CoV-2 fusion peptide, the fusion peptide epitope adopts a helical structure and includes the arginine residue at the S2' cleavage site. COV44-79 limited disease caused by SARS-CoV-2 in a Syrian hamster model. These findings highlight the fusion peptide as a candidate epitope for next-generation coronavirus vaccine development.


Assuntos
Anticorpos Monoclonais , Anticorpos Antivirais , Anticorpos Amplamente Neutralizantes , COVID-19 , Epitopos , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/química , Vacinas contra COVID-19/imunologia , Epitopos/química , Epitopos/imunologia , Humanos , Peptídeos/imunologia , Conformação Proteica em alfa-Hélice , Domínios Proteicos , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia
19.
Infect Immun ; 79(12): 4876-92, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21947773

RESUMO

Interleukin-10 (IL-10) modulates inflammatory responses elicited in vitro and in vivo by Borrelia burgdorferi, the Lyme disease spirochete. How IL-10 modulates these inflammatory responses still remains elusive. We hypothesize that IL-10 inhibits effector functions of multiple genes induced by B. burgdorferi in macrophages to control concomitantly elicited inflammation. Because macrophages are essential in the initiation of inflammation, we used mouse J774 macrophages and live B. burgdorferi spirochetes as the model target cell and stimulant, respectively. First, we employed transcriptome profiling to identify genes that were induced by stimulation of cells with live spirochetes and that were perturbed by addition of IL-10 to spirochete cultures. Spirochetes significantly induced upregulation of 347 genes at both the 4-h and 24-h time points. IL-10 inhibited the expression levels, respectively, of 53 and 65 of the 4-h and 24-h genes, and potentiated, respectively, at 4 h and 24 h, 65 and 50 genes. Prominent among the novel identified IL-10-inhibited genes also validated by quantitative real-time PCR (qRT-PCR) were Toll-like receptor 1 (TLR1), TLR2, IRAK3, TRAF1, IRG1, PTGS2, MMP9, IFI44, IFIT1, and CD40. Proteome analysis using a multiplex enzyme-linked immunosorbent assay (ELISA) revealed the IL-10 modulation/and or potentiation of RANTES/CCL5, macrophage inflammatory protein 2 (MIP-2)/CXCL2, IP-10/CXCL10, MIP-1α/CCL3, granulocyte colony-stimulating factor (G-CSF)/CSF3, CXCL1, CXCL5, CCL2, CCL4, IL-6, tumor necrosis factor alpha (TNF-α), IL-1α, IL-1ß, gamma interferon (IFN-γ), and IL-9. Similar results were obtained using sonicated spirochetes or lipoprotein as stimulants. Our data show that IL-10 alters effectors induced by B. burgdorferi in macrophages to control concomitantly elicited inflammatory responses. Moreover, for the first time, this study provides global insight into potential mechanisms used by IL-10 to control Lyme disease inflammation.


Assuntos
Borrelia burgdorferi/fisiologia , Perfilação da Expressão Gênica , Interleucina-10/farmacologia , Doença de Lyme/metabolismo , Macrófagos/metabolismo , Animais , Borrelia burgdorferi/efeitos dos fármacos , Linhagem Celular , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamação/metabolismo , Inflamação/prevenção & controle , Doença de Lyme/patologia , Macrófagos/efeitos dos fármacos , Macrófagos/microbiologia , Camundongos , Reação em Cadeia da Polimerase em Tempo Real
20.
Sci Rep ; 11(1): 6612, 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33758294

RESUMO

Mid-infrared (IR) spectral region is of immense importance for astronomy, medical diagnosis, security and imaging due to the existence of the vibrational modes of many important molecules in this spectral range. Therefore, there is a particular interest in miniaturization and integration of IR optical components. To this end, 2D van der Waals (vdW) crystals have shown great potential owing to their ease of integration with other optoelectronic platforms and room temperature operation. Recently, 2D vdW crystals of [Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text] have been shown to possess the unique phenomenon of natural in-plane biaxial hyperbolicity in the mid-infrared frequency regime at room temperature. Here, we report a unique application of this in-plane hyperbolicity for designing highly efficient, lithography free and extremely subwavelength mid-IR photonic devices for polarization engineering. In particular, we show the possibility of a significant reduction in the device footprint while maintaining an enormous extinction ratio from [Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text] [Formula: see text] based mid-IR polarizers. Furthermore, we investigate the application of sub-wavelength thin films of these vdW crystals towards engineering the polarization state of incident mid-IR light via precise control of polarization rotation, ellipticity and relative phase. We explain our results using natural in-plane hyperbolic anisotropy of [Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text] [Formula: see text] via both analytical and full-wave electromagnetic simulations. This work provides a lithography free alternative for miniaturized mid-infrared photonic devices using the hyperbolic anisotropy of [Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text] [Formula: see text].

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