RESUMO
A anemia infecciosa equina é uma importante enfermidade que acomete os equídeos em todo o mundo, se apresentando de forma aguda, crônica e assintomática causando grandes prejuízos para a economia tanto para criadores que vivem do trabalho desses animais quantos aos criadores que investem no melhoramento das raças, impedindo o acesso ao mercado tanto nacional quanto internacional. O Ministério da Agricultura, Pecuária e Abastecimento considera o IDGA como teste oficial para diagnóstico dessa enfermidade, porém essa técnica é demorada e muita vez acaba sendo subjetiva, dependendo da experiencia particular de cada Laboratorista. Além de não conseguir detectar animais no início da infecção. Logo, a necessidade de se buscar novas técnicas como o ELISA indireto que aperfeiçoem o tempo de análise dos resultados, facilita a automação e obtém resultados confiáveis. O estudo realizado teve como objetivo padronizar uma técnica de ELISA indireto utilizando uma proteína de envelope viral GP90 como antígeno para diagnóstico da anemia infecciosa equina. Avaliando o desempenho do teste a partir da sensibilidade, especificidade e valores preditivos positivo e negativo. Os valores obtidos foram: 91,11%, 93,33%, 91,11% e 93,33% respectivamente. Concluiu-se que o teste apresenta bom desempenho, além da possibilidade de detectar amimais positivos no início da infecção.
Equine infectious anemia is an important disease that affects horses all over the world, presenting in an acute, chronic and asymptomatic way, causing great damage to the economy, both for breeders who live off the work of these animals and for breeders who invest in the improvement of breeds, preventing access to both national and international markets. The Ministry of Agriculture, Livestock and Food Supply considers AGID to be the official test for diagnosing this disease, but this technique takes time and often ends up being subjective, depending on the particular experience of each laboratory worker. In addition to not being able to detect animals at the beginning of the infection. Therefore, the need to seek new techniques such as indirect ELISA that improve the time of analysis of results, facilitate automation and obtain reliable results. The aim of this study was to standardize an indirect ELISA technique using a GP90 viral envelope protein as an antigen for the diagnosis of equine infectious anemia. Evaluating test performance based on sensitivity, specificity and positive and negative predictive values. The values obtained were 91.11%, 93.33%, 91.11 and 93.33 respectively. It was concluded that the test performs well, in addition to the possibility of detecting positive animals at the beginning of the infection.
Assuntos
Animais , Ensaio de Imunoadsorção Enzimática/veterinária , Proteínas do Envelope Viral/análise , Técnicas Imunoenzimáticas/veterinária , Anemia Infecciosa Equina/diagnóstico , Vírus da Anemia Infecciosa Equina , Cavalos/imunologia , Antígenos Virais/análiseRESUMO
INTRODUCTION: Dengue virus replication has been considered mainly cytoplasmic, however, studies indicate that some flaviviruses may use the intranuclear pathway as part of the machinery that the virus uses to increase infection capacity in the host cell. This paper describes alterations at nuclear level in the cell infected with dengue, which are likely involved in the virus replication processes. OBJECTIVE: This paper addresses the ultrastructural observations of C6/36 cells of the Aedes albopictus mosquito infected with dengue virus type 2. MATERIALS AND METHODS: C6/36 cells were infected in culture medium with the serum of a patient positively diagnosed for dengue 2. Subsequently, the cells were incubated for 10 days and the cytopathic effect was assessed. The cells were processed for immunofluorescence assays and transmission electron microscopy. RESULTS: The immunofluorescence assays confirmed the presence of viral protein E associated with cellular syncytia in the culture. In the ultrastructural study, the infected cells showed vesicular-tubular structures and dilated cisterns of the endoplasmic reticulum at the cytoplasmic level. Viral particles were found exclusively in cytoplasm localized within the vacuoles. Nuclei of cellular syncytia showed membrane structures arranged in a circular shape and, in some cases, these syncytia displayed lysis; in no case viral particles were observed at the nuclear level. CONCLUSIONS: The ultrastructural alterations of nuclei in cells infected with the dengue virus using electron microscopy techniques had not been reported before, as far as we know. It is likely that such modifications are associated with replicative processes at an intranuclear level as an alternate replication mechanism.
Assuntos
Núcleo Celular/ultraestrutura , Efeito Citopatogênico Viral , Vírus da Dengue/fisiologia , Aedes/citologia , Animais , Linhagem Celular , Citoplasma/virologia , Dengue/virologia , Vírus da Dengue/isolamento & purificação , Células Gigantes/virologia , Humanos , Microscopia Eletrônica , Microscopia de Fluorescência , Vacúolos/virologia , Proteínas do Envelope Viral/análise , Viremia/virologia , Replicação ViralRESUMO
ABSTRACT Introduction: Dengue virus replication has been considered mainly cytoplasmic, however, studies indicate that some flaviviruses may use the intranuclear pathway as part of the machinery that the virus uses to increase infection capacity in the host cell. This paper describes alterations at nuclear level in the cell infected with dengue, which are likely involved in the virus replication processes. Objective: This paper addresses the ultrastructural observations of C6/36 cells of the Aedes albopictus mosquito infected with dengue virus type 2. Materials and methods: C6/36 cells were infected in culture medium with the serum of a patient positively diagnosed for dengue 2. Subsequently, the cells were incubated for 10 days and the cytopathic effect was assessed. The cells were processed for immunofluorescence assays and transmission electron microscopy. Results: The immunofluorescence assays confirmed the presence of viral protein E associated with cellular syncytia in the culture. In the ultrastructural study, the infected cells showed vesicular-tubular structures and dilated cisterns of the endoplasmic reticulum at the cytoplasmic level. Viral particles were found exclusively in cytoplasm localized within the vacuoles. Nuclei of cellular syncytia showed membrane structures arranged in a circular shape and, in some cases, these syncytia displayed lysis; in no case viral particles were observed at the nuclear level. Conclusions: The ultrastructural alterations of nuclei in cells infected with the dengue virus using electron microscopy techniques had not been reported before, as far as we know. It is likely that such modifications are associated with replicative processes at an intranuclear level as an alternate replication mechanism.
RESUMEN Introducción. La replicación del virus del dengue se ha considerado principalmente citoplásmica; sin embargo, en diversos estudios se ha informado que algunos flavivirus pueden utilizar factores intranucleares como parte de la maquinaria que utilizan para aumentar la capacidad de infección en la célula huésped. En este trabajo se describen las alteraciones a nivel nuclear en células infectadas con dengue, probablemente involucradas en procesos de replicación viral. Objetivo. Presentar las observaciones ultraestructurales de células C6/36 de Aedes albopictus infectadas con el virus del dengue de tipo 2. Materiales y métodos. Se infectaron células C6/36 con suero de un paciente con diagnóstico de dengue 2; posteriormente, se mantuvieron en medio de cultivo durante 10 días y se evaluó el efecto citopático. Las células se procesaron para los ensayos de inmunofluorescencia y microscopía electrónica de transmisión, con el fin de hacer el estudio ultraestructural. Resultados. Los ensayos de inmunofluorescencia confirmaron la presencia de la proteína E viral asociada con sincitios celulares en el cultivo. En el estudio ultraestructural, las células infectadas tenían estructuras vesiculares y tubulares, y cisternas dilatadas del retículo endoplásmico en el citoplasma. Las partículas virales se encontraron exclusivamente en vacuolas localizadas en el citoplasma. Los núcleos de los sincitios celulares contenían estructuras de membrana dispuestas en forma circular y, en algunos casos, dichos sincitios presentaban lisis. En ningún caso se observaron partículas virales en el núcleo. Conclusiones. No se habían reportado alteraciones ultraestructurales en los núcleos de células infectadas con el virus del dengue detectadas mediante técnicas de microscopia electrónica. Es probable que tales modificaciones estén asociadas con procesos intranucleares de replicación como un mecanismo alternativo.
Assuntos
Animais , Humanos , Núcleo Celular/ultraestrutura , Efeito Citopatogênico Viral , Vírus da Dengue/fisiologia , Vacúolos/virologia , Viremia/virologia , Replicação Viral , Microscopia Eletrônica , Células Gigantes/virologia , Linhagem Celular , Proteínas do Envelope Viral/análise , Aedes/citologia , Citoplasma/virologia , Dengue/virologia , Vírus da Dengue/isolamento & purificação , Microscopia de FluorescênciaAssuntos
Falência Hepática Aguda/etiologia , Falência Hepática Aguda/patologia , Rubéola (Sarampo Alemão)/complicações , Rubéola (Sarampo Alemão)/diagnóstico , Brasil , Criança , Evolução Fatal , Feminino , Humanos , Imuno-Histoquímica , Fígado/patologia , Microscopia , Proteínas do Envelope Viral/análiseRESUMO
One of the factors limiting the search of new compounds based on the structure of target proteins involved in diseases is the limited amount of target structural information. Great advances in the search for lead compounds could be achieved to find new cavities in protein structures that are generated using well established computational chemistry tools. In the case of dengue, the discovery of pockets in the crystallographic structure of the E protein has contributed to the search for lead compounds aimed at interfering in conformational transitions involved in the pH-dependent fusion process. This is a complex mechanism triggered by the acid pH of the endosomes that leads to the initial changes in the E protein assembly at the virus surface. In the present work, an arrangement of three ectodomain portions of the E protein present on the surface of the mature dengue virus was studied through long all-atom molecular dynamics simulations with explicit solvent. In order to identify new pockets and to evaluate the influence of the acid pH on these pockets, the physiological neutral pH conditions and the acid pH of the endosomes that trigger the fusion process were modeled. Several pockets presenting pH-dependent characteristics were found in the contact regions between the chains. Pockets at the protein-protein interfaces induced by a monomer in another monomer were also found. Some of the pockets are good candidates for the design of lead compounds that could interfere in the rearrangements in E proteins along the fusion process contributing to the development of specific inhibitors of the dengue disease.
Assuntos
Vírus da Dengue/química , Proteínas do Envelope Viral/química , Concentração de Íons de Hidrogênio , Modelos Moleculares , Simulação de Dinâmica Molecular , Conformação Proteica , Dobramento de Proteína , Proteínas do Envelope Viral/análiseRESUMO
A chitosan-modified carbon fiber electrode (CFE) for dengue virus envelope protein (DENV) was developed. Antibodies against DENV were covalently immobilized on the chitosan (CHIT) matrix after activation with sodium periodate. Cyclic voltammetries and scanning electron microscopies analysis were performed to monitor steps involved in the CFE surface modification. Amperometric response of the competitive immunoassays was generated by hydrogen peroxide reaction with the peroxidase conjugated to DENV and 2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) as mediator. The immunosensor showed a lower limit of detection for DENV (0.94 ng mL(-1)) than previously described and a linear range from 1.0 to 175 ng mL(-1), in concentration levels clinically relevant for dengue virus diagnosis. The intra- and inter-assay were respectively 5.8% and 3.6%. The unique and simple design of this immunoassay format provides an economical alternative for the manufacture of other sensitive sensors.
Assuntos
Vírus da Dengue/isolamento & purificação , Eletrodos/normas , Proteínas do Envelope Viral/análise , Carbono , Fibra de Carbono , Quitosana , Dengue/diagnóstico , Vírus da Dengue/imunologia , Imunoensaio/métodos , Imunoensaio/normas , Proteínas do Envelope Viral/imunologiaRESUMO
Bovine Viral Diarrhea Virus (BVDV) is the causative agent of a worldwide disease. The virus infects bovines of all ages, causing reproductive problems and contaminating biological products of high commercial value. The large-scale production of BVDV vaccines presents the challenge of processing antigenic proteins that are highly susceptible to the processing environment. Potency testing requires the immunization of cattle in order to determine the neutralizing antibodies titers induced by the vaccine. An alternative to the in vivo test is an in vitro measurement of key viral antigens. This paper describes the development and validation of a sandwich-type indirect ELISA that is able to detect and quantify BVDV E2 glycoprotein in live and inactivated BVDV. Validation parameters such as repeatability, intermediate precision, and reproducibility indicated that the developed ELISA constitutes an advanced tool for evaluating the BVDV antigen throughout manufacturing and vaccine release testing.
Assuntos
Antígenos Virais , Vírus da Diarreia Viral Bovina/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Proteínas do Envelope Viral , Vacinas Virais , Animais , Antígenos Virais/análise , Antígenos Virais/genética , Antígenos Virais/imunologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/imunologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Células CHO , Bovinos , Cricetinae , Cricetulus , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Vacinas de Produtos Inativados/imunologia , Proteínas do Envelope Viral/análise , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Vacinas Virais/imunologiaRESUMO
Classical swine fever virus is the etiological agent of the most economically important highly contagious disease of swine worldwide. E2 is the major envelope glycoprotein present as a homodimer on the outer surface of the virus and represents an important target for the induction of neutralizing immune response against the viral infection. The E2 extracellular domain was expressed in the milk of adenoviral transduced goats at the highest level about 1.2g/L. The recombinant glycoprotein was purified from clarified serum milk by a single metal chelate affinity chromatography step, as a homodimer of approximately 100kDa and purity over 98%. Glycosylation analysis showed the presence of oligomannoside, hybrid and complex type N-glycans, attached to the recombinant E2. The capacity of goat milk-derived E2 antigen to protect pigs from both classical swine fever clinical signs and viral infection was assessed in a vaccination and challenge trial. The immunized pigs became protected after challenge with 10(5) LD(50) of a highly pathogenic CSFV strain. In the context of veterinary vaccines, this expression system has the advantages that the recombinant antigen could be harvested in about 48h after adenoviral transduction with expression levels in the range of g/L. This approach may turn into a scalable expression system for the assessment and production of veterinary vaccines.
Assuntos
Adenoviridae/genética , Vírus da Febre Suína Clássica/imunologia , Peste Suína Clássica/prevenção & controle , Cabras , Glândulas Mamárias Animais/metabolismo , Proteínas do Envelope Viral/biossíntese , Vacinas Virais/imunologia , Adenoviridae/fisiologia , Animais , Temperatura Corporal , Linhagem Celular , Dimerização , Glicosilação , Histidina , Humanos , Injeções Intramusculares , Leite/química , Leite/imunologia , Oligopeptídeos , Oligossacarídeos/metabolismo , Suínos , Fatores de Tempo , Transdução Genética , Proteínas do Envelope Viral/análise , Proteínas do Envelope Viral/imunologia , Proteínas do Envelope Viral/isolamento & purificação , Vacinas Virais/biossíntese , Vacinas Virais/genéticaRESUMO
It was recently reported that disease severity increased during the 1997 Cuban dengue 2 virus epidemic and it was suggested that this might be explained by the appearance of neutralization resistant escape mutants. We investigated these observations and ideas by sequencing 20 dengue 2 virus isolates obtained during the early (low case fatality rate) and the late (high case fatality rate) phases of the outbreak. Our results showed total conservation of the E gene sequence for these isolates suggesting that the selection of envelope gene escape mutants was not the determinant of increased disease severity. Alignment of these sequences with those available in GenBank, followed by Maximum likelihood phylogenetic analysis generated a tree, which indicated that our isolates are closely related to the virus that circulated in Venezuela in 1997/98 and subsequently in Martinique in 1998. This "American/Asian" genotype has therefore gradually dispersed across the Caribbean region during the past 5 years.
Assuntos
Vírus da Dengue/genética , Dengue/epidemiologia , Surtos de Doenças , Proteínas do Envelope Viral/genética , Cuba/epidemiologia , Dengue/mortalidade , Vírus da Dengue/isolamento & purificação , Humanos , Epidemiologia Molecular , Dados de Sequência Molecular , Filogenia , Proteínas do Envelope Viral/análiseRESUMO
In this study, 13 samples of liver biopsies from patients with chronic hepatitis C were studied by transmission electron microscopy (EM) and immunoelectron microscopy (IEM). The 13 biopsies showed ultrastructural cell damage typical of acute viral hepatitis. In four of the 13 liver biopsies enveloped virus-like particles (VLPs) inside cytoplasmic vesicles and in the cytoplasm of hepatocytes were observed. We also detected the presence of unenveloped VLPs mainly in the cytoplasm and in the endoplasmic reticulum. IEM using anti-core, E1 and E2 monoclonal antibodies (mAbs) confirmed the specific localization of these proteins, in vivo, inside cytoplasm and endoplasmic reticulum. Thus, this work provided evidence for hepatocellular injury related to HCV infection. It also suggested the presence of HCV-related replicating structures in the cytoplasm of hepatocytes and raised the possibility of hepatitis C virion morphogenesis in intracellular vesicles.