Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
1.
Mil Med ; 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33428750

RESUMO

INTRODUCTION: Dengue fever, caused by any of the four dengue viruses (DENV1-4), is endemic in more than 100 countries around the world. Each year, up to 400 million people get infected with dengue virus. It is one of the most important arthropod-borne viral diseases. Dengue's global presence poses a medical threat to deploying military personnel and their dependents. An accurate diagnosis followed by attentive supportive care can improve outcomes in patients with severe dengue disease. Dengue diagnostic tests based on PCR and ELISA platforms have been developed and cleared by the U.S. FDA. However, these diagnostic assays are laborious and usually require highly trained personnel and specialized equipment, which presents a significant challenge when conducting operations in austere and resource-constrained areas. InBios International, Inc. (Seattle, WA) has developed two rapid and instrument-free immunochromatographic test prototype devices (multiplex and traditional formats) for dengue diagnosis. MATERIALS AND METHODS: To determine the performance of the InBios immunochromatographic tests, 183 clinical samples were tested on both prototype devices. Both assays were performed without any instruments and the results were read in 20 minutes. RESULTS: The traditional format had better overall performance (sensitivity: 97.4%; specificity: 90%) than the multiplex format (sensitivity: 86.9%; specificity: 63.3%). The traditional format was superior in serotype-specific detection with 100% overall sensitivity for DENV1, DENV3, and DENV4 and 93.3% sensitivity for DENV2 compared to the multiplex format (91.7%, 78.3%, 83.3%, and 96.3% for DENV1, 2, 3, and 4, respectively). The traditional format was easier to read than the multiplex format. The multiplex format was simpler and faster to set up than the traditional format. CONCLUSIONS: The InBios traditional format had a better overall performance and readability profile than the multiplex format, while the multiplex format was easier to set up. Both formats were highly sensitive and specific, were easy to perform, and did not require sophisticated equipment. They are ideal for use in resource-limited settings where dengue is endemic. Based on our overall assessment, the traditional format should be considered for further development and used in the upcoming multicenter clinical trial toward FDA clearance.

2.
Inflamm Res ; 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-33037881

RESUMO

OBJECTIVE AND DESIGN: This systematic review aims to establish the role of CD8 + T lymphocytes in COPD. METHODS: Forty-eight papers published in the last 15 years were identified for inclusion. RESULTS: CD8 + T-cells are increased in the lungs of patients with COPD (17 studies, 16 positive) whereas in the circulation, findings were inconclusive. Activation of CD8 + T-cells was enhanced in lungs (four studies, three positive) but cell phenotype was unclear. There was substantial evidence of a higher proportion of type 1 CD8 + (Tc1) cells in COPD (11 studies, 9 positive), though the population of type 2 (Tc2) cells was also increased (5 studies, 4 positive). CD8 + T-cells in COPD exhibited greater expression of cytotoxic proteins (five studies, five positive). Studies assessed a variety of questions so evidence was insufficient to draw firm conclusions. The role of CD8 + T-cells at acute exacerbation of COPD and also their contribution to alveolar destruction can only be hypothesised at this stage. CONCLUSIONS: Not only is the number of CD8 + T-cells increased in COPD, these cells have increased capacity to exert effector functions and are likely to contribute to disease pathogenesis. Several mechanisms highlighted show promise for future investigation to consolidate current knowledge.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32518668

RESUMO

Introduction and background: A tetravalent DNA vaccine for Dengue virus is under development but has not yet achieved optimal immunogenicity. Salivary glands vaccination has been reported efficacious in rodents and dogs. We report on a pilot study testing the salivary gland as a platform for a Dengue DNA vaccine in a non-human primate model. Materials and methods: Four cynomolgus macaques were used in this study. Each macaque was pre-medicated with atropine and sedated with ketamine. Stensen's duct papilla was cannulated with a P10 polyethylene tube, linked to a 500ul syringe. On the first two infusions, all macaques were infused with 300ul of TVDV mixed with 2 mg of zinc. For the 3rd infusion, to increase transfection into salivary tissue, two animals received 100uL TVDV mixed with 400uL polyethylenimine 1µg/ml (PEI) and the other two animals received 500uL TVDV with zinc. Antibody titers were assessed 4 weeks following the second and third infusion. Results and conclusions: SGRI through Stensen's duct is a well-tolerated, simple and easy to reproduce procedure. TVDV infused into macaques salivary glands elicited a significantly weaker antibody response than with different delivery methods.

5.
Vaccine ; 38(17): 3313-3320, 2020 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-32184032

RESUMO

Dengue fever, caused by dengue viruses (DENV 1-4) is a leading cause of illness and death in the tropics and subtropics. Therefore, an effective vaccine is urgently needed. Currently, the only available licensed dengue vaccine is a chimeric live attenuated vaccine that shows varying efficacy depending on serotype, age and baseline DENV serostatus. Accordingly, a dengue vaccine that is effective in seronegative adults, children of all ages and in immunocompromised individuals is still needed. We are currently researching the use of psoralen to develop an inactivated tetravalent dengue vaccine. Unlike traditional formalin inactivation, psoralen inactivates pathogens at the nucleic acid level, potentially preserving envelope protein epitopes important for protective anti-dengue immune responses. We prepared highly purified monovalent vaccine lots of formalin- and psoralen-inactivated DENV 1-4, using Capto DeVirS and Capto Core 700 resin based column chromatography. Tetravalent psoralen-inactivated vaccines (PsIV) and formalin-inactivated vaccines (FIV) were prepared by combining the four monovalent vaccines. Mice were immunized with either a low or high dose of PsIV or FIV to evaluate the immunogenicity of monovalent as well as tetravalent formulations of each inactivation method. In general, the monovalent and tetravalent PsIVs elicited equivalent or higher titers of neutralizing antibodies to DENV than the FIV dengue vaccines and this response was dose dependent. The immunogenicity of tetravalent dengue PsIVs and FIVs were also evaluated in nonhuman primates (NHPs). Consistent with what was observed in mice, significantly higher neutralizing antibody titers for each dengue serotype were observed in the NHPs vaccinated with the tetravalent dengue PsIV compared to those vaccinated with the tetravalent dengue FIV, indicative of the importance of envelope protein epitope preservation during psoralen inactivation of DENV.

6.
Proc Natl Acad Sci U S A ; 117(10): 5502-5509, 2020 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-32098843

RESUMO

The habenula, an ancient small brain area in the epithalamus, densely expresses nicotinic acetylcholine receptors and is critical for nicotine intake and aversion. As such, identification of strategies to manipulate habenular activity may yield approaches to treat nicotine addiction. Here we show that GPR151, an orphan G-protein-coupled receptor (GPCR) highly enriched in the habenula of humans and rodents, is expressed at presynaptic membranes and synaptic vesicles and associates with synaptic components controlling vesicle release and ion transport. Deletion of Gpr151 inhibits evoked neurotransmission but enhances spontaneous miniature synaptic currents and eliminates short-term plasticity induced by nicotine. We find that GPR151 couples to the G-alpha inhibitory protein Gαo1 to reduce cyclic adenosine monophosphate (cAMP) levels in mice and in GPR151-expressing cell lines that are amenable to ligand screens. Gpr151- knockout (KO) mice show diminished behavioral responses to nicotine and self-administer greater quantities of the drug, phenotypes rescued by viral reexpression of Gpr151 in the habenula. These data identify GPR151 as a critical modulator of habenular function that controls nicotine addiction vulnerability.


Assuntos
Habenula/fisiologia , Plasticidade Neuronal/fisiologia , Nicotina/metabolismo , Agonistas Nicotínicos/metabolismo , Receptores Acoplados a Proteínas-G/fisiologia , Transtornos Relacionados ao Uso de Substâncias/metabolismo , Animais , Células CHO , Cricetulus , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Habenula/metabolismo , Humanos , Camundongos Knockout , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/genética , Nicotina/administração & dosagem , Agonistas Nicotínicos/administração & dosagem , Receptores Acoplados a Proteínas-G/genética , Transmissão Sináptica/genética , Transmissão Sináptica/fisiologia
7.
Mil Med ; 185(Suppl 1): 624-627, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31498402

RESUMO

INTRODUCTION: Leptospirosis is a global zoonotic disease spread through contact with contaminated water/soil. The US soldiers at the military bases in these countries are extremely vulnerable, as most of them are immunologically naïve to the responsible pathogen. No recent sero-epidemiological data of leptospirosis among US Marines stationed in Japan were available. MATERIALS AND METHODS: In this study, we analyzed the presence of leptospirosis in US Marines stationed in Japan. One thousand posttour sera samples were analyzed by enzyme-linked immunosorbent assay for Leptospira-specific Immunoglobulin G. RESULTS: Among these 1,000 posttour samples, 85 of them were positive and corresponding pretour samples were analyzed by enzyme-linked immunosorbent assay also. Seroconversion occurred for 35 (3.5%) Marines during their assignment to Japan. These results also indicate that 50 Marine personnels were exposed to leptospires before their assignment to Japan, perhaps because of previous exposure to leptospires at home. CONCLUSION: The 5% rate of seroconversion in 2013 and 2014 suggests that leptospirosis is a potential threat for Marines in the endemic region in Japan.

8.
Nature ; 574(7778): 372-377, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31619789

RESUMO

Diabetes is far more prevalent in smokers than non-smokers, but the underlying mechanisms of vulnerability are unknown. Here we show that the diabetes-associated gene Tcf7l2 is densely expressed in the medial habenula (mHb) region of the rodent brain, where it regulates the function of nicotinic acetylcholine receptors. Inhibition of TCF7L2 signalling in the mHb increases nicotine intake in mice and rats. Nicotine increases levels of blood glucose by TCF7L2-dependent stimulation of the mHb. Virus-tracing experiments identify a polysynaptic connection from the mHb to the pancreas, and wild-type rats with a history of nicotine consumption show increased circulating levels of glucagon and insulin, and diabetes-like dysregulation of blood glucose homeostasis. By contrast, mutant Tcf7l2 rats are resistant to these actions of nicotine. Our findings suggest that TCF7L2 regulates the stimulatory actions of nicotine on a habenula-pancreas axis that links the addictive properties of nicotine to its diabetes-promoting actions.


Assuntos
Transtornos do Metabolismo de Glucose/genética , Habenula/metabolismo , Transdução de Sinais , Tabagismo/complicações , Proteína 2 Semelhante ao Fator 7 de Transcrição/metabolismo , Animais , AMP Cíclico/metabolismo , Glucose/metabolismo , Transtornos do Metabolismo de Glucose/metabolismo , Humanos , Camundongos , Mutagênese , Nicotina/metabolismo , Células PC12 , Pâncreas/metabolismo , Ratos , Receptores Nicotínicos/metabolismo , Tabagismo/genética , Tabagismo/metabolismo , Proteína 2 Semelhante ao Fator 7 de Transcrição/genética
9.
MSMR ; 26(7): 18-23, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31347372

RESUMO

The Naval Infectious Diseases Diagnostic Laboratory (NIDDL) serves as a reference clinical laboratory that supports Department of Defense (DoD) military treatment facilities worldwide in the detection and identification of high-risk and emerging infectious diseases. Since the emergence of Zika virus (ZIKV) in the Western Hemisphere in 2016, the NIDDL has been a central hub for ZIKV testing for DoD personnel and beneficiaries. Samples collected during patients' clinical evaluations were screened for evidence of possible exposure to ZIKV using molecular and serological methods. An in-house ZIKV plaque reduction neutralization test was used to confirm the presence of ZIKV immunoglobulin M antibody. Of 1,420 individuals tested, ZIKV infection was confirmed by quantitative real-time polymerase chain reaction (PCR) assay in 11 (0.8%); an additional 26 recent flaviviral infections (possibly ZIKV) were identified based on serology (1.8%). These findings contribute to the understanding of the burden of ZIKV infections among DoD personnel and beneficiaries and highlight the role of the NIDDL in clinical diagnosis during emerging infectious disease outbreaks.


Assuntos
Infecção por Zika virus/epidemiologia , Adulto , Feminino , Humanos , Masculino , Militares/estatística & dados numéricos , Gravidez , Reação em Cadeia da Polimerase em Tempo Real/métodos , Estados Unidos/epidemiologia , Zika virus/isolamento & purificação , Infecção por Zika virus/sangue , Infecção por Zika virus/transmissão , Infecção por Zika virus/urina
10.
Vaccine ; 37(32): 4444-4453, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31279565

RESUMO

Phase 1 clinical trials with a DNA vaccine for dengue demonstrated that the vaccine is safe and well tolerated, however it produced less than optimal humoral immune responses. To determine if the immunogenicity of the tetravalent dengue DNA vaccine could be enhanced, we explored alternate, yet to be tested, methods of vaccine administration in non-human primates. Animals were vaccinated on days 0, 28 and 91 with either a low (1 mg) or high (5 mg) dose of vaccine by the intradermal or intramuscular route, using either needle-free injection or electroporation devices. Neutralizing antibody, IFN-γ T cell and memory B cell responses were compared to a high dose group vaccinated with a needle-free intramuscular injection delivery device similar to what had been used in previous preclinical and clinical studies. All previously untested vaccination methodologies elicited improved immune responses compared to the high dose needle-free intramuscular injection delivery group. The highest neutralizing antibody responses were observed in the group that was vaccinated with the high dose formulation via intradermal electroporation. The highest IFN-γ T cell responses were also observed in the high dose intradermal electroporation group and the CD8+ T cells were the dominant contributors for the IFNγ response. Memory B cells were detected for all four serotypes. More than a year after vaccination, groups were challenged with dengue-1 virus. Both the low and high dose intradermal electroporation groups had significantly fewer days of dengue-1 virus RNAemia compared to the control group. The results from this study demonstrate that using either an electroporation device and/or the intradermal route of delivery increases the immune response generated by this vaccine in non-human primates and should be explored in humans.


Assuntos
Vacinas contra Dengue/imunologia , Imunogenicidade da Vacina/imunologia , Vacinas de DNA/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Linfócitos T CD8-Positivos/imunologia , Dengue/imunologia , Dengue/prevenção & controle , Vírus da Dengue/imunologia , Sistemas de Liberação de Medicamentos/métodos , Eletroporação/métodos , Injeções Intradérmicas/métodos , Injeções Intramusculares/métodos , Interferon gama/imunologia , Macaca fascicularis/imunologia , Vacinação/métodos
11.
Sci Rep ; 9(1): 1109, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30710094

RESUMO

Antibody (Ab)-dependent enhancement (ADE) is a hypothesized mechanism of increased disease severity during secondary dengue virus (DENV) infection. This study investigates Ab-dependent cell cytotoxicity (ADCC) in counteracting ADE. In our system, DENV and DENV-immune sera were added to peripheral blood mononuclear cells (PBMCs), and ADE and NK cell activation were simultaneously monitored. ADE was detected in monocytes and a concurrent activation of NK cells was observed. Activated NK cells expressed IFN-γ and CD107a. IFN-γ was detected at 24 hours (24 h) followed by a rapid decline; CD107a expression peaked at 48 h and persisted for >7 days. Optimal activation of NK cells required the presence of enhancement serum together with ADE-affected monocytes and soluble factors, suggesting the coexistence of the counteractive ADCC Abs, in the same ADE-serum, capable of strongly promoting NK cell activation. The function of NK cells against ADE was demonstrated using a depletion assay. NK cell-depleted PBMCs had increased ADE as compared to whole PBMCs. Conversely, adding activated NK cells back into the NK-depleted-PBMCs or to purified monocytes decreased ADE. Blocking IFN-γ expression also increased ADE. The study suggests that under ADE conditions, NK cells can be activated by ADCC Abs and can control the magnitude of ADE.


Assuntos
Vírus da Dengue/fisiologia , Dengue/imunologia , Células Matadoras Naturais/imunologia , Anticorpos Antivirais/metabolismo , Citotoxicidade Celular Dependente de Anticorpos , Anticorpos Facilitadores , Apresentação do Antígeno , Degranulação Celular , Células Cultivadas , Reações Cruzadas , Humanos , Soros Imunes , Imunomodulação , Interferon gama/metabolismo , Ativação Linfocitária , Depleção Linfocítica , Replicação Viral
12.
PLoS One ; 13(7): e0200576, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30024910

RESUMO

Group C orthobunyaviruses (GRCVs) are a complex of viruses in the genus Orthobunyavirus and are associated with human febrile disease in tropical and subtropical areas of South and Central America. While numerous GRCVs have been isolated from mosquitoes, animals, and humans, genetic analysis of these viruses is limited. In this study, we characterized 65 GRCV isolates from febrile patients identified through clinic-based surveillance in the northern and southern Peruvian Amazon. A 500 base pair region of the S segment and 750 base pair regions of the M and L segments were sequenced. Pairwise sequence analysis of the clinical isolates showed nucleotide identities ranging from 68% to 100% and deduced amino acid sequence identities ranging from 72% to 100%. Sequences were compared with reference strains of the following GRCVs: Caraparu virus (CARV), Murutucu virus (MURV), Oriboca virus (ORIV), Marituba virus (MTBV), Itaqui virus (ITQV), Apeu virus (APEUV), and Madrid virus (MADV). Sequence comparison of clinical isolates with the prototype strains based on the S and L segments identified two clades; clade I included isolates with high genetic association with CARV-MADV, and clade II included isolates with high genetic association with MURV, ORIV, APEUV, and MTBV. Genetic relationships based on the M segment were at time inconsistent with those based on the S and L segments. However, clade groupings based on the M segment were highly consistent with relationships based on microneutralization assays. These results advance our understanding of the genetic and serologic relationships of GRCVs circulating in the Peruvian Amazon.


Assuntos
Genoma Viral/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Orthobunyavirus/genética , RNA Viral/genética , Adolescente , Adulto , Infecções por Bunyaviridae/virologia , Criança , Feminino , Genoma Viral/imunologia , Geografia , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Orthobunyavirus/classificação , Orthobunyavirus/fisiologia , Peru , Filogenia , RNA Viral/imunologia , Especificidade da Espécie , Adulto Jovem
13.
Vaccine ; 35(45): 6103-6111, 2017 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-28987439

RESUMO

BACKGROUND: This study was to compare B and T memory cells elicited by a single dose monovalent 2009 influenza A (H1N1) vaccine (strain A/California/7/2009 H1N1) in HIV+ and HIV- groups, and to analyze the impact of the prior seasonal vaccines to the immunogenicity of this vaccine. METHODS: Blood samples were collected before vaccination (day 0) and at days 28 and 180. Participants were categorized into HIV-/LAIV, HIV-/TIV and HIV+/TIV subgroups according to the trivalent live-attenuated or inactivated (LAIV or TIV) seasonal influenza vaccines they received previously. The IgG+ memory B cells (BMem) and IFNγ+ T cells were measured against antigens including the H1N1 vaccine, the hemagglutinin (HA) and neuraminidase (NA) proteins or peptide pools of the pandemic and the seasonal H1N1 strains, respectively. RESULTS: Overall BMem responses increased significantly at day 28 but returned to baseline by day 180 in all three subgroups. The average frequency of the H1N1-specific BMem at day 28 for the HIV-/LAIV, HIV-/TIV and HIV+/TIV groups was 2.14%, 1.26% and 1.67%, respectively, and the average fold change was 14.39, 3.81 and 3.93, respectively. The differences of BMem between HIV-/LAIV and the two TIV subgroups were significant. For the IFNγ response, the overall spot counts ranged widely between 0 and 958/106 PBMCs. The group average spot counts to H1N1 vaccine was 89, 102, and 30 at day 28 for HIV-/LAIV, HIV-/TIV and HIV+/TIV subgroups, respectively. The average increase of IFNγ response at day 28 vs day 0 in all three subgroups did not reach 2-fold. CONCLUSION: Participants with a prior LAIV seasonal vaccine, as compared to a TIV seasonal vaccine, responded significantly better to the monovalent H1N1 vaccine. Excluding LAIV participants, no difference was seen between the HIV+ and HIV- subject groups in terms of BMem. The BMem response declined at 6months.


Assuntos
Linfócitos B/imunologia , Infecções por HIV/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Linfócitos T/imunologia , Anticorpos Antivirais/imunologia , Humanos , Influenza Humana/virologia , Vacinação/métodos , Vacinas de Produtos Inativados/imunologia
14.
J Virol Methods ; 248: 7-18, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28624584

RESUMO

This study describes an antibody-dependent NK cell degranulation assay, as a biomarker to assess antibody-dependent cellular cytotoxicity (ADCC) response in influenza plasma and for antibody therapies against influenza infection. The concentration of neutralizing antibodies (NAbs) against the hemagglutinin receptor of influenza viruses is a current determinant in protection against infection, particularly following receipt of the seasonal influenza vaccine. However, this is a limited assessment of protection, because: (i) NAb titers that incur full protection vary; and (ii) NAb titers do not account for the entire breadth of antibody responses against viral infection. Previous reports have indicated that antibodies that prime ADCC play a vital role in controlling influenza infections, and thus should be quantified for assessing protection against influenza. This report demonstrates a non-radioactive assay that assesses NK cell activation as a marker of ADCC, in which NK cells interact with opsonized viral antigen expressed on the surface of infected Raji target cells resulting in effector cell degranulation (surrogate CD107a expression). A positive correlation was determined between HAI titers and sustained NK cell activation, although NK cell activation was seen in plasma samples with HAI titers below 40 and varied amongst samples with high HAI titers. Furthermore, sustained NK cell degranulation was determined for influenza-vaccinated transchromosomic bovine intravenous immunoglobulin, indicating the potential utility of this therapy for influenza treatment. We conclude that this assay is reproducible and relevant.


Assuntos
Citotoxicidade Celular Dependente de Anticorpos , Imunoensaio , Imunoglobulinas Intravenosas/uso terapêutico , Vírus da Influenza A Subtipo H1N1/imunologia , Influenza Humana/imunologia , Influenza Humana/terapia , Células Matadoras Naturais/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Biomarcadores/sangue , Bovinos , Degranulação Celular , Linhagem Celular , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Imunoglobulinas Intravenosas/administração & dosagem , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Influenza Humana/sangue , Influenza Humana/virologia , Ativação Linfocitária , Proteína 1 de Membrana Associada ao Lisossomo/imunologia
15.
J Immunol Methods ; 441: 24-30, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27856192

RESUMO

The study assessed antibody-dependent NK cell degranulation, a biomarker relevant to antibody-dependent cell cytotoxicity (ADCC), to analyze dengue immune sera. We first determined binding intensity of patient sera to the surface of DENV-infected cells and examined the types of antigens expressed on infected cells. Antigens from pre-membrane (PreM) and envelope (E), but not from NS proteins were detected on the surface of infected cells. After adding NK cells to infected target cells previously treated with patient sera, rapid NK cell degranulation was observed. Non-neutralizing patient sera generated comparable NK cell degranulation as that of neutralizing sera, suggesting ADCC may be a protective mechanism apart from Ab neutralization. The level of NK cell degranulation varied dramatically among human individuals and was associated with the level of CD16 expression on NK cells, informing on the complexity of ADCC among human population.


Assuntos
Anticorpos Neutralizantes/imunologia , Citotoxicidade Celular Dependente de Anticorpos , Degranulação Celular , Vírus da Dengue/imunologia , Dengue/imunologia , Células Matadoras Naturais/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/imunologia , Humanos , Receptores de IgG/genética , Receptores de IgG/imunologia
16.
BMC Biol ; 14(1): 117, 2016 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-28034300

RESUMO

BACKGROUND: Increasing evidence suggests that influenza reassortment not only contributes to the emergence of new human pandemics but also plays an important role in seasonal influenza epidemics, disease severity, evolution, and vaccine efficacy. We studied this process within 2091 H3N2 full genomes utilizing a combination of the latest reassortment detection tools and more conventional phylogenetic analyses. RESULTS: We found that the amount of H3N2 intra-subtype reassortment depended on the number of sampled genomes, occurred with a steady frequency of 3.35%, and was not affected by the geographical origins, evolutionary patterns, or previous reassortment history of the virus. We identified both single reassortant genomes and reassortant clades, each clade representing one reassortment event followed by successful spread of the reassorted variant in the human population. It was this spread that was mainly responsible for the observed high presence of H3N2 intra-subtype reassortant genomes. The successfully spread variants were generally sampled within one year of their formation, highlighting the risk of their rapid spread but also presenting an opportunity for their rapid detection. Simultaneous spread of several different reassortant lineages was observed, and despite their limited average lifetime, second and third generation reassortment was detected, as well as reassortment between viruses belonging to different vaccine-associated clades, likely displaying differing antigenic properties. Some of the spreading reassortants remained confined to certain geographical regions, while others, sharing common properties in amino acid positions of the HA, NA, and PB2 segments, were found throughout the world. CONCLUSIONS: Detailed surveillance of seasonal influenza reassortment patterns and variant properties may provide unique information needed for prediction of spread and construction of future influenza vaccines.


Assuntos
Vírus da Influenza A Subtipo H3N2/genética , Evolução Molecular , Genoma Viral/genética , Humanos , Vírus da Influenza A Subtipo H3N2/classificação , Influenza Humana/transmissão , Influenza Humana/virologia , Filogenia
17.
Biomed Res Int ; 2016: 5253842, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27446953

RESUMO

Secondary dengue infection by heterotypic serotypes is associated with severe manifestations of disease, that is, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The World Health Organization (WHO) has recommended criteria based on the hemagglutination inhibition (HI) test to distinguish between primary and secondary dengue infections. Since the HI test has practical limitations and disadvantages, we evaluated the accuracy of WHO HI criteria and compared it with criteria based on an IgG enzyme-linked immunosorbent assay (ELISA) using a plaque reduction neutralization test (PRNT) as the gold standard. Both WHO HI criteria and IgG ELISA criteria performed strongly (16/16) in determining primary infection. However, to determine secondary infection, the IgG ELISA criteria performed better (72/73) compared to the WHO HI criteria (23/73).


Assuntos
Coinfecção/sangue , Vírus da Dengue/isolamento & purificação , Dengue/sangue , Testes de Inibição da Hemaglutinação/métodos , Adolescente , Adulto , Criança , Coinfecção/imunologia , Coinfecção/virologia , Dengue/imunologia , Dengue/virologia , Vírus da Dengue/imunologia , Vírus da Dengue/patogenicidade , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Técnica de Placa Hemolítica/métodos , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , Testes de Neutralização/métodos
18.
J Clin Microbiol ; 54(7): 1766-1773, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27098955

RESUMO

Dengue virus (DENV) and chikungunya virus (CHIKV) are important human pathogens with common transmission vectors and similar clinical presentations. Patient care may be impacted by the misdiagnosis of DENV and CHIKV in areas where both viruses cocirculate. In this study, we have developed and validated a one-step multiplex reverse transcriptase PCR (RT-PCR) to simultaneously detect, quantify, and differentiate between four DENV serotypes (pan-DENV) and chikungunya virus. The assay uses TaqMan technology, employing two forward primers, three reverse primers, and four fluorophore-labeled probes in a single-reaction format. Coextracted and coamplified RNA was used as an internal control (IC), and in vitro-transcribed DENV and CHIKV RNAs were used to generate standard curves for absolute quantification. The diagnostic 95% limits of detection (LOD) within the linear range were 50 and 60 RNA copies/reaction for DENV (serotypes 1 to 4) and CHIKV, respectively. Our assay was able to detect 53 different strains of DENV, representing four serotypes, and six strains of CHIKV. No cross-reactivity was observed with related flaviviruses and alphaviruses, To evaluate diagnostic sensitivity and specificity, 89 clinical samples positive or negative for DENV (serotypes 1 to 4) and CHIKV by the standard virus isolation method were tested in our assay. The multiplex RT-PCR assay showed 95% sensitivity and 100% specificity for DENV and 100% sensitivity and specificity for CHIKV. With an assay turnaround time of less than 2 h, including extraction of RNA, the multiplex quantitative RT-PCR assay provides rapid diagnosis for the differential detection of two clinically indistinguishable diseases, whose geographical occurrence is increasingly overlapping.


Assuntos
Febre de Chikungunya/diagnóstico , Vírus Chikungunya/isolamento & purificação , Vírus da Dengue/isolamento & purificação , Dengue/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Humanos , Reação em Cadeia da Polimerase Multiplex/métodos , Sensibilidade e Especificidade , Fatores de Tempo
19.
PLoS Negl Trop Dis ; 10(2): e0004390, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26872216

RESUMO

BACKGROUND: Dengue has emerged as one of the most important infectious diseases in the last five decades. Evidence indicates the expansion of dengue virus endemic areas and consequently the exponential increase of dengue virus infections across the subtropics. The clinical manifestations of dengue virus infection include sudden fever, rash, headache, myalgia and in more serious cases, spontaneous bleeding. These manifestations occur in children as well as in adults. Defining the epidemiology of dengue in a given area is critical to understanding the disease and devising effective public health strategies. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report the results from a prospective cohort study of 4380 adults in West Java, Indonesia, from 2000-2004 and 2006-2009. A total of 2167 febrile episodes were documented and dengue virus infections were confirmed by RT-PCR or serology in 268 cases (12.4%). The proportion ranged from 7.6 to 41.8% each year. The overall incidence rate of symptomatic dengue virus infections was 17.3 cases/1,000 person years and between September 2006 and April 2008 asymptomatic infections were 2.6 times more frequent than symptomatic infections. According to the 1997 WHO classification guidelines, there were 210 dengue fever cases, 53 dengue hemorrhagic fever cases (including one dengue shock syndrome case) and five unclassified cases. Evidence for sequential dengue virus infections was seen in six subjects. All four dengue virus serotypes circulated most years. Inapparent dengue virus infections were predominantly associated with DENV-4 infections. CONCLUSIONS/SIGNIFICANCE: Dengue virus was responsible for a significant percentage of febrile illnesses in an adult population in West Java, Indonesia, and this percentage varied from year to year. The observed incidence rate during the study period was 43 times higher than the reported national or provincial rates during the same time period. A wide range of clinical severity was observed with most infections resulting in asymptomatic disease. The circulation of all four serotypes of dengue virus was observed in most years of the study.


Assuntos
Vírus da Dengue/classificação , Vírus da Dengue/isolamento & purificação , Dengue/epidemiologia , Dengue/patologia , Adolescente , Adulto , Idoso , Dengue/virologia , Vírus da Dengue/genética , Feminino , Humanos , Incidência , Indonésia/epidemiologia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Estudos Prospectivos , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Adulto Jovem
20.
Vector Borne Zoonotic Dis ; 16(1): 20-5, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26771425

RESUMO

To expand the documentation of rickettsioses in Indonesia, we conducted an ectoparasite and small mammal investigation involving four major islands: Java, Sumatra, Sulawesi, and Kalimantan. Coastal and highland regions on each island surveyed were chosen to represent different ecologies in Indonesia. Indication of the presence of Rickettsia spp. was evident in all areas sampled. Typhus group rickettsiae-specific antibodies had significantly higher prevalence among small mammals captured in Java compared to the other islands surveyed (78% in coastal and 50% in highland regions) and the prevalence of spotted fever group rickettsiae-specific antibodies was significantly higher in Kalimantan than the other islands investigated. Hosts and vectors were restricted by Rickettsia spp. but not by coastal or highland regions. Our findings expand the range in which rickettsial pathogens have been documented within the Indonesian archipelago and point to a significant risk to human health.


Assuntos
Mamíferos , Infecções por Rickettsia/veterinária , Animais , Anticorpos Antibacterianos/sangue , Ectoparasitoses/parasitologia , Ectoparasitoses/veterinária , Humanos , Indonésia/epidemiologia , Reação em Cadeia da Polimerase em Tempo Real , Infecções por Rickettsia/sangue , Infecções por Rickettsia/epidemiologia , Infecções por Rickettsia/microbiologia , Estudos Soroepidemiológicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...