Padronização de um ELISA indireto a partir da utilização de uma proteína de superfície do vírus da anemia infecciosa equina como antígeno para o diagnóstico dessa enfermidade / Standardization of an indirect ELISA using a surface protein of the equine infectious anemia virus as an antigen for the diagnosis of this disease

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.

As dimensões da precarização do trabalho em face da pandemia de Covid-19 / The dimensions of job insecurity due to the COVID-19 pandemic / Las dimensiones de la precarización del trabajo en virtud de la pandemia de Covid-19

Resumo A precarização do trabalho consiste em fenômeno com dinâmica notadamente acentuada desde a década de 1970, em resposta à crise estrutural do capital. Com a emergência da pandemia de Covid-19, as suas dimensões ganharam visibilidade, agravando, em especial, a questão da saúde dos trabalhadores. Diante disso, a pesquisa que originou este artigo teve o objetivo de analisar aspectos da relação entre precarização e pandemia, tomando a realidade brasileira como particularidade analítica. Trata-se de pesquisa teórica, realizada com base em documentos oficiais e notícias veiculadas na internet, submetidos a uma análise materialista histórica. Constatou-se que todas as dimensões da precarização do trabalho estabelecem determinação recíproca com a pandemia. O simulacro do combate ao desemprego pela via da precarização, o home office e a uberização são componentes que se destacam na conjuntura pandêmica, inclusive provocando reações dos trabalhadores contra esse processo, vide manifestações durante a pandemia. Por conta disso, esses aspectos devem ser objeto de especial atenção por parte da ciência e, sobretudo, das lutas da classe trabalhadora, ainda com maior ênfase após a pandemia.

Abstract The job insecurity is a phenomenon with dynamics markedly accentuated since the 1970s, in response to the structural crisis of capital. With the emergence of the COVID-19 pandemic, its dimensions gained visibility, worsening, in particular, the issue of workers' health. Therefore, the research that originated this article aimed to analyze aspects of the relationship between insecurity and pandemic, taking the Brazilian reality as an analytical feature. It is a theoretical research, carried out based on official documents and news published on the internet, submitted to a historical materialist analysis. We found that all dimensions of precarious work establish reciprocal determination with the pandemic. The simulacrum of combating unemployment through precariousness, the home office and uberization are components that stand out in the pandemic situation, including provoking workers' reactions against this process, see demonstrations during the pandemic. Because of this, these aspects should be the object of special attention by science and, above all, by the struggles of the working class, with even greater emphasis after the pandemic.

Resumen La precarización del trabajo consiste en un fenómeno con dinámica ampliamente acentuada desde la década de 1970, como respuesta a la crisis estructural del capital. Con la emergencia de la pandemia de Covid-19, sus dimensiones ganaron visibilidad, agravando, en especial, lo relativo a la salud de los trabajadores. Ante eso, la investigación que originó este artículo tuvo el objetivo de analizar aspectos entre precarización y pandemia, tomando la realidad brasileña como particularidad analítica. Se trata de una investigación teórica, realizada con base en documentos oficiales y noticias dadas en la internet, sometidos a un análisis materialista histórico. Se constató que todas las dimensiones de la precarización del trabajo establecen determinación recíproca con la pandemia. La simulación del combate al desempleo por la vía de la precarización, el home office y la uberización son componentes que se destacan en la coyuntura pandémica, incluso provocando reacciones de los trabajadores contra ese proceso, vide manifestaciones durante la pandemia. Por lo cual, esos aspectos deben ser objeto de especial atención por parte de la ciencia y, sobre todo, de las luchas de la clase trabajadora, aun con mayor énfasis después de la pandemia.

Epitope of dengue virus E protein detect human antibodies associated with mild disease: a potential peptide for vaccine development

ABSTRACT The antigenic potential of seven immunogenic peptides of the dengue virus was evaluated in the sera of patients with dengue confirmed by IgM/IgG serology. Antibodies IgM and IgG against dengue virus peptides were analyzed by ELISA in 31 dengue sero-positive and 20 sero-negative patients. The P5 peptide showed significant IgG immunoreactivity mostly in the sera of patients with dengue without warning signs in comparison with patients with dengue with warning signs, correlating with mild disease. This finding suggests that the low antibody response against P5 epitope could be a risk factor for higher susceptibility to dengue virus infection with warning signs, and that P5 could be a potential antigen for vaccine development.

Nuclei ultrastructural changes of C6/36 cells infected with virus dengue type 2 / Cambios ultraestructurales en núcleos de células C6/36 infectadas con virus dengue de tipo 2

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.

Características de la estructura molecular de las proteínas E del virus del Zika y E1 del virus de la rubéola y posibles implicaciones en el neurotropismo y en las alteraciones del sistema nervioso / E-ZIKV and E1-RV proteins molecular structure and their potential implications in neurotropism and nervous system disorders

Resumen Introducción. El virus del Zika (ZIKV) es un flavivirus con envoltura, transmitido a los seres humanos principalmente por el vector Aedes aegypti. La infección por ZIKV se ha asociado con un gran neurotropismo y con efectos neuropáticos, como el síndrome de Guillain-Barré en el adulto y la microcefalia fetal y posnatal, así como con un síndrome de infección congénita similar al producido por el virus de la rubéola (RV). Objetivo. Comparar las estructuras moleculares de la proteína de envoltura E del virus del Zika (E-ZIKV) y de la E1 del virus de la rubéola (E1-RV), y plantear posibles implicaciones en el neurotropismo y en las alteraciones del sistema nervioso asociadas con el ZIKV. Materiales y métodos. La secuencia de aminoácidos de la proteína E-ZIKV (PDB: 5iZ7) se alineó con la de la glucopreteína E1 del virus de la rubéola (PDB: 4ADG). Los elementos de la estructura secundaria se determinaron usando los programas Vector NTI Advance®, DSSP y POSA, así como herramientas de gestión de datos (AlignX®). Uno de los criterios principales de comparación y alineación fue la asignación de residuos estructuralmente equivalentes, con más de 70 % de identidad. Resultados. La organización estructural de la proteína E-ZIKV (PDB: 5iZ7) fue similar a la de E1-RV (PDB: 4ADG) (70 a 80 % de identidad), y se observó una correspondencia con la estructura definida para las glucoproteínas de fusión de membrana de clase II de los virus con envoltura. E-ZIKV y E1-RV exhibieron elementos estructurales de fusión muy conservados en la región distal del dominio II, asociados con la unión a los receptores celulares de entrada del virus de la rubéola (glucoproteína de mielina del oligodendrocito, Myelin Oligodendrocyte Glycoprotein, MOG), y con los receptores celulares Axl del ZIKV y de otros flavivirus. Conclusión. La comparación de las proteínas E-ZIKV y E1-RV es un paso necesario hacia la definición de otros factores moleculares determinantes del neurotropismo y la patogenia del ZIKV, el cual puede contribuir a generar estrategias de diagnóstico, prevención y tratamiento de las complicaciones neurológicas inducidas por el ZIKV.

Abstract Introduction: Zika virus (ZIKV) is an enveloped flavivirus transmitted to humans mainly by Aedes aegypti. ZIKV infection has been associated with high neurotropism and neuropathic effects such as the Guillain-Barré syndrome in adults, and fetal and postnatal microcephaly and the congenital Zika virus syndrome similar to that produced by rubella virus (VR). Objective: To compare Zika virus membrane protein E (E-ZIKV) and rubella virus membrane protein E1 (E1-RV), and to propose possible implications for neurotropism and nervous system disorders associated with ZIKV infections. Materials and methods: The amino acid sequence of E-ZIKV protein (PDB: 5iZ7) was aligned to that of rubella virus glycoprotein E1 (PDB: 4ADG). The secondary structure elements were determined using the programs Vector NTI Advance®, DSSP, and POSA, and integrated data management tools (AlignX®). One of the main comparison and alignment criteria was the allocation of structurally equivalent residues with more than 70% identity. Results: E-ZIKV structural organization (PDB: 5iZ7) was similar to that of E1-RV (PDB: 4ADG) (70%-80% identity), and it was consistent with relevant structural features of viral membrane class II fusion glycoproteins. E-ZIKV and E1-RV exhibited highly conserved fusion structural elements at the distal region of domain II, which has been associated with the RV myelin oligodendrocyte glycoprotein and Axl cell receptors in ZIKV and other flaviviruses. Conclusion: The comparison of E-ZIKV and E1-RV proteins constitutes an essential step towards the definition of ZIKV neurotropism and pathogenesis molecular determinants, and for the adoption of diagnosis, prevention and treatment strategies against neurological complications induced by ZIKV infection.

Mutations in the S gene and in the overlapping reverse transcriptase region in chronic hepatitis B Chinese patients with coexistence of HBsAg and anti-HBs

Abstract Background The mechanism underlying the coexistence of hepatitis B surface antigen and antibodies to HBsAg in chronic hepatitis B patients remains unknown. Aims This research aimed to determine the clinical and virological features of the rare pattern. Methods A total of 32 chronic hepatitis B patients infected by HBV genotype C were included: 15 carrying both HBsAg and anti-HBs (group I) and 17 solely positive for HBsAg (group II). S gene and reverse transcriptase region sequences were amplified, sequenced and compared with the reference sequences. Results The amino acid variability within major hydrophilic region, especially the “a” determinant region, and within reverse transcriptase for regions overlapping the major hydrophilic region in group I is significantly higher than those in group II. Mutation sI126S/T within the “a” determinant was the most frequent change, and only patients from group I had the sQ129R, sG130N, sF134I, sG145R amino acid changes, which are known to alter immunogenicity. Conclusions In chronic patients, the concurrent HBsAg/anti-HBs serological profile is associated with an increased aa variability in several key areas of HBV genome. Additional research on these genetic mutants are needed to clarify their biological significance for viral persistence.

Molecular identification of Saint Louis encephalitis virus genotype IV in Colombia

Saint Louis encephalitis virus (SLEV) is a member of the Japanese-encephalitis virus serocomplex of the genus Flavivirus. SLEV is broadly distributed in the Americas and the Caribbean Islands, where it is usually transmitted by mosquitoes of the genus Culex and primarily to birds and mammalian-hosts. Humans are occasionally infected by the virus and are dead-end hosts. SLEV causes encephalitis in temperate regions, while in tropical regions of the Americas, several human cases and a wide biological diversity of SLEV-strains have been reported. The phylogenetic analysis of the envelope (E) protein genes indicated eight-genotypes of SLEV with geographic overlap. The present paper describes the genotyping of two SLEV viruses detected in mosquito-pools collected in northern Colombia (department of Cordoba). We used reverse transcription-polymerase chain reaction to amplify a fragment of theE-gene to confirm the virus identity and completeE-gene sequencing for phylogenetic analysis and genotyping of the two-SLEV viruses found circulating in Córdoba. This is the first report of SLEV genotype IV in Colombia (Córdoba) in mosquitoes from a region of human inhabitation, implicating the risk of human disease due to SLEV infection. Physicians should consider SLEV as a possible aetiology for undiagnosed febrile and neurologic syndromes among their patients who report exposure to mosquito-bites.

Receptor expression and responsiveness of human peripheral blood mononuclear cells to a human cytomegalovirus encoded CC chemokine

Human cytomegalovirus is a ubiquitous pathogen that infects the majority of the world's population. After long period of time co-evolving with human being, this pathogen has developed several strategies to evade host immune surveillance. One of the major trick is encoding homologous to those of the host organism or stealing host cellular genes that have significant functions in immune system. To date, we have found several viral immune analogous which include G protein coupled receptor, class I major histocompatibility complex and chemokine. Chemokine is a small group of molecules which is defined by the presence of four cysteines in highly conserved region. The four kinds of chemokines (C, CC, CXC, and CX3C) are classified based on the arrangement of 1 or 2 N-terminal cysteine residues. UL128 protein is one of the analogous that encoded by human cytomegalovirus that has similar amino acid sequences to the human CC chemokine. It has been proved to be one of the essential particles that involved in human cytomegalovirus entry into epithelial/endothelial cells as well as macrophages. It is also the target of potent neutralizing antibodies in human cytomegalovirus-seropositive individuals. We had demonstrated the chemotactic trait of UL128 protein in our previous study. Recombinant UL128 in vitrohas the ability to attract monocytes to the infection region and enhances peripheral blood mononuclear cell proliferation by activating the MAPK/ERK signaling pathway. However, the way that this viral encoded chemokine interacting with peripheral blood mononuclear cells and the detailed mechanism that involving the virus entry into host cells keeps unknown. Here we performed in vitroinvestigation into the effects of UL128 protein on peripheral blood mononuclear cell's activation and receptor binding, which may help us further understand the immunomodulatory function of UL128 protein as well as human cytomegalovirus diffusion mechanism.

Recombinant hepatitis C virus-envelope protein 2 interactions with low-density lipoprotein/CD81 receptors

Hepatitis C virus (HCV) envelope protein 2 (E2) is involved in viral binding to host cells. The aim of this work was to produce recombinant E2B and E2Y HCV proteins in Escherichia coli and Pichia pastoris, respectively, and to study their interactions with low-density lipoprotein receptor (LDLr) and CD81 in human umbilical vein endothelial cells (HUVEC) and the ECV304 bladder carcinoma cell line. To investigate the effects of human LDL and differences in protein structure (glycosylated or not) on binding efficiency, the recombinant proteins were either associated or not associated with lipoproteins before being assayed. The immunoreactivity of the recombinant proteins was analysed using pooled serum samples that were either positive or negative for hepatitis C. The cells were immunophenotyped by LDLr and CD81 using flow cytometry. Binding and binding inhibition assays were performed in the presence of LDL, foetal bovine serum (FCS) and specific antibodies. The results revealed that binding was reduced in the absence of FCS, but that the addition of human LDL rescued and increased binding capacity. In HUVEC cells, the use of antibodies to block LDLr led to a significant reduction in the binding of E2B and E2Y. CD81 antibodies did not affect E2B and E2Y binding. In ECV304 cells, blocking LDLr and CD81 produced similar effects, but they were not as marked as those that were observed in HUVEC cells. In conclusion, recombinant HCV E2 is dependent on LDL for its ability to bind to LDLr in HUVEC and ECV304 cells. These findings are relevant because E2 acts to anchor HCV to host cells; therefore, high blood levels of LDL could enhance viral infectivity in chronic hepatitis C patients.

Notícias do Levantamento de Recursos e Necessidades de Enfermagem na Revista Brasileira de Enfermagem (1955-1958) / News of the Inquiry about Nursing Needs and Resources in the Brazilian Journal of Nursing (1955-1958) / Noticias del Levantamiento de Necesidades y Recursos de Enfermería en la Revista Brasileña de Enfermería (1955-1958)

Estudo Histórico Social que tem como objeto notícias sobre o Levantamento de Recursos e Necessidades de Enfermagem no Brasil, publicadas na Revista Brasileira de Enfermagem entre 1955 e 1958. A fonte primária foi constituída pelos exemplares da Revista Brasileira de Enfermagem, publicados dentro do recorte temporal do estudo. As fontes secundárias foram constituídas por livros, artigos, dissertações e teses relativas à história da Enfermagem. A análise dos dados teve apoio das fontes secundárias e do pensamento do sociólogo Pierre Bourdieu. Os dados evidenciaram que a Revista Brasileira de Enfermagem, além de oportunizar a divulgação de notícias acerca do Levantamento, proporcionou visibilidade ao mesmo mediante a veiculação dessas notícias e, por fim, teve o efeito simbólico de conferir poder e prestígio à Enfermagem Brasileira.

Social historical study that has as object news related to the Assessment of the Resources and Needs of Nursing in Brazil published in the Revista Brasileira de Enfermagem between 1955 and 1958. The primary source is constituted of copies of Revista Brasileira de Enfermagem published within the selected period of the study. The secondary sources are constituted of books, papers, dissertations and thesis related to the Nursing history. The data analysis was supported by the secondary sources and the thought of the sociologist Pierre Bourdieu. The results evidenced that Revista Brasileira de Enfermagem, in addition to making possible the dissemination of news about the Assessment provided visibility to it and, at last, had the symbolic effect of giving power and prestige to the Brazilian Nursing.

Estudio Histórico Social que tiene como objeto noticias referentes al Levantamiento de Recursos y Necesidades de Enfermería en Brasil publicadas en la Revista Brasileira de Enfermagem entre 1955 y 1958. La fuente primaria se constituye de los ejemplares de la Revista Brasileira de Enfermagem publicados dentro del recorte temporal do estudio. Las fuentes secundarias están constituidas de libros, artículos disertaciones y tesis relativas a la historia de la Enfermería. El análisis de los datos tuvo apoyo de las fuentes secundarias y del pensamiento del Sociólogo Pierre Bourdieu. Los resultados evidencian que la Revista Brasileira de Enfermagem, además de posibilitar la divulgación de noticias acerca del Levantamiento proporcionó visibilidad al mismo mediante la divulgación de esas noticias y, por fin, tuve el efecto simbólico de conferir poder y prestigio a la Enfermería Brasileña.

Inflammatory response of endothelial cells to hepatitis C virus recombinant envelope glycoprotein 2 protein exposure

The hepatitis C virus (HCV) encodes approximately 10 different structural and non-structural proteins, including the envelope glycoprotein 2 (E2). HCV proteins, especially the envelope proteins, bind to cell receptors and can damage tissues. Endothelial inflammation is the most important determinant of fibrosis progression and, consequently, cirrhosis. The aim of this study was to evaluate and compare the inflammatory response of endothelial cells to two recombinant forms of the HCV E2 protein produced in different expression systems (Escherichia coli and Pichia pastoris). We observed the induction of cell death and the production of nitric oxide, hydrogen peroxide, interleukin-8 and vascular endothelial growth factor A in human umbilical vein endothelial cells (HUVECs) stimulated by the two recombinant E2 proteins. The E2-induced apoptosis of HUVECs was confirmed using the molecular marker PARP. The apoptosis rescue observed when the antioxidant N-acetylcysteine was used suggests that reactive oxygen species are involved in E2-induced apoptosis. We propose that these proteins are involved in the chronic inflammation caused by HCV.

Selección de variantes de virus dengue sensibles a la heparina en células BHK-21 / Selection of heparin-sensitive dengue virus variants in BHK-21 cells

Estudios previos han demostrado que la adaptación de diversos virus a crecer en líneas celulares de vertebrados, conduce a la selección de variantes virales que unen al heparán sulfato (HS) con alta afinidad. En el presente trabajo se determinó la susceptibilidad de cepas del virus dengue (DENV) a la heparina hipersulfatada un análogo al HS, después de pases seriados en células BHK-21. A aislados de campo de los cuatro serotipos de DENV, se les realizaron ocho pases seriados en células BHK-21. La adaptación de los DENV al cultivo celular seleccionó variantes virales con una aumentada capacidad replicativa en células BHK-21 y una incrementada susceptibilidad a la heparina, en relación a las respectivas cepas no adaptadas, obteniéndose una inhibición de la infectividad más significativa en DENV-2 y DENV-4. Las cepas de DENV adaptadas presentaron cambios en la secuencia de aminoácidos de la proteína de envoltura (E), en particular una substitución K204R para DENV-1, N67K para DENV-2, K308R y V452A para DENV-3 y E327G para DENV-4. Estas sustituciones implicaron ganancia de residuos básicos que incrementaron la carga neta positiva de la proteína. Los resultados sugieren, que la adaptación de cepas de DENV a células BHK-21 selecciona variantes virales sensibles a la heparina y que la efectividad de este compuesto varía dependiendo de la cepa viral. Además sugieren que el HS puede jugar un papel importante en la infectividad de las cepas de DENV adaptadas al cultivo celular, a diferencia de los aislados de DENV no adaptados.

Several studies have shown that adaptation of various viruses to grow in certain cell lines of vertebrates, leads to the selection of virus variants that bind heparan sulfate (HS) with high affinity. In this study we investigated the susceptibility of strains of dengue virus (DENV) to oversulfated heparin an analogue of HS after passages in BHK-21 cells. Field isolates of the four serotypes of DENV with a limited number of passes in mosquito cells C6/36HT were serially passaged eight times in BHK-21 cells. The adaptation of the DENV to the cell culture selected viral variants with an increased replicative capacity in BHK-21 cells and an increased susceptibility to heparin compared with the original not adapted strains, with a more significant inhibition of the infectivity in DENV-2 and DENV-4.The E protein of the adapted strains showed changes in the amino acid sequence, particularly at the position K204R to DENV-1, N67K to DENV-2, K308R and V452A for DENV-3 and E327G to DENV-4. These substitutions implicated a gain of basic residues that increased the net positive charge of the protein. These results suggest that adaptation of DENV strains to BHK-21 cells implies changes in the envelope protein, changes associated to the protein reactivity with heparin, the inhibitory effectiveness of this compound varying depending on the viral strain. In addition, these results suggest that the HS can play an important role in the infectivity of the DENV strains adapted to vertebrate cell culture, but not in the infectivity of non-adapted DENV isolates.

Formulação vacinal trivalente voltada para o controle profilático/terapêutico de tumores induzidos pelo vírus do papiloma humano tipo 16 (HPV-16) e infecções pelos vírus da imunodeficiência adquirida (HIV) e herpes vírus humano (HSV) / Trivalent vaccine formulation focused on the prophylactic / therapeutic control of tumors induced by human papillomavirus type 16 (HPV-16) and infection by human immunodeficiency virus (HIV) and human herpes virus (HSV)

As proteínas E7 (HPV), p24 (HIV) e gD (HSV) são exclusivamente expressas por células infectadas ou tumorais e, por isso, são utilizadas como alvos para vacinas com características terapêuticas. Foram desenvolvidas duas vacinas de DNA capazes de expressar as três proteínas virais por meio de um vetor de expressão bicistrônico baseado na sequência IRES. As vacinas, denominadas pIRES I e pIRES II, diferem entre si por transportarem os genes que codificam as proteínas E7 do HPV-16 e p24 do HIV fusionadas à proteína gD do HSV-1 em ordem inversa. Células COS-7 transfectadas com os plasmídeos vacinais expressaram as proteínas alvo, como determinado por imunofluorecência com anticorpos específicos para as proteínas gD, p24 e E7. As vacinas foram testadas em modelo murino quanto à capacidade de gerar anticorpos e células T CD8+ específicas. Observamos que animais vacinados desenvolveram baixas taxas de anticorpos contra gD, p24 e E7. Em contrapartida, demonstramos a indução de células T CD8+ específicas para os três antígenos testados. Os plasmídeos vacinais foram capazes de proteger camundongos inoculados com células tumorais TC-1 (que expressam a proteína E7 do HPV-16), embora apresentando diferentes níveis de proteção em ensaios profiláticos e terapêuticos. As formulações foram testadas em relação à capacidade de proteger animais frente a desafio com o HSV-1 sendo que apenas um deles gerou efeito protetor. Em conclusão, os resultados demonstram que vacinas voltadas para o controle terapêutico de infecções ou processos tumorais associados aos vírus HPV, HIV e HSV representam uma meta viável e promissora

The proteins E7 (HPV), p24 (HIV) and gD (HSV) are exclusively expressed by infected cells or tumors and therefore are used as targets for vaccines with therapeutic characteristics. We developed two DNA vaccines capable of expressing these three viral proteins using a bicistronic expression vector based on IRES sequence. The plasmid vaccines, named pIRES I and pIRES II, differ by carrying the genes that encode proteins of HPV-16 E7 and p24 fused to the HIV protein gD of HSV-1 in reverse order. Transfected COS-7 cells expressed the target proteins, as determined by immunofluorescence with specific antibodies for gD, p24 and E7. The vaccines were tested in mice for their ability to generate antibodies and specific CD8+ T cells. We observed that vaccinated animals developed low levels of antibodies against gD, E7 and p24. In contrast, we demonstrate the induction of specific CD8+ T cells for the three antigens. The plasmid vaccines were able to protect mice inoculated with TC-1 tumor cells (which express the E7 protein of HPV-16), although with different levels of protection in prophylactic and therapeutic trials. The formulations were tested for ability to protect animals against challenge with HSV-1 and only one of them generated a protective effect. In conclusion, the results show that vaccines directed to therapeutic control of infections or tumor process associated with HPV, HSV or HIV represents a promising and viable goal

Virus del dengue de serotipo 1 (DENV-1) de Colombia: su contribución a la presentación del dengue en el departamento de Santander / Dengue virus serotype 1 (DENV-1) from Colombia: its contribution to dengue occurrence in Santander

Introducción. Los cuatro serotipos del virus del dengue circularon en el departamento de Santander entre 1998 y 2008. No existe información sobre el papel del serotipo 1 (DENV-1) en la epidemiología de la enfermedad. Objetivo. Analizar la relación entre el cambio de predominancia del (DENV-1) con su diversificación genética, predominancia de los otros serotipos y presentación del dengue grave. Materiales y métodos. La diversificación genética se estudió por análisis filogenético usando la secuencia del gen E de 12 cepas del virus. Para el análisis se utilizaron datos sobre predominancia de los serotipos obtenidos en estudios previos y datos oficiales de incidencia del dengue. Resultados. Los virus seleccionados se agruparon en el genotipo V junto a (DENV-1) de países de Latinoamérica y se evidenció segregación en cuatro linajes. Los cambios en la predominancia del virus coincidieron con el reemplazo de linaje y esto, a su vez, con incremento en la prevalencia de DENV-2 y DENV-3, e incremento del dengue grave. Conclusión. La diversificación genética podría contribuir a cambios de predominancia de (DENV-1), y la relación del virus con el DENV-2 y DENV-3 en situaciones que favorecen la presentación de casos graves. Se necesitan más estudios para precisar el papel de los serotipos en la epidemiología del dengue.

Introduction: Between 1998 and 2008 all dengue virus serotypes circulated in the Departamento de Santander, an endemic region in northeastern Colombia. No information is available as to the role of serotype 1 (DENV-1) with respect to epidemiology of dengue. Objective: To analyze the relationship between changes in DENV-1 predominance with respect to genetic diversity, prevalence of others serotypes and occurrence of severe dengue. Methods: Virus genetic diversity was studied by phylogenetic analysis comparing E gene sequences from 12 viral strains. Data about serotypes predominance obtained in previous studies and official data about dengue incidence were used for analysis. Results: Selected viruses grouped into genotype V together DENV-1 from Latin America countries, and segregation in four lineages was evidenced. Changes in virus predominance coincided with replacement of lineage, increase in prevalence of DENV-2 and DENV-3 and increase of severe dengue. Conclusion: Genetic divergence could have contributed to changes in DENV-1 predominance. The relationship of the virus with DENV-2 and DENV-3 could create scenarios that promote occurrence of severe cases. More studies are required to ascertain the precise role of serotypes in the epidemiology of dengue.

Production and diagnostic application of recombinant domain III of West Nile envelope protein in Brazil

INTRODUCTION: West Nile virus (WNV) is a flavivirus with a natural cycle involving mosquitoes and birds. Over the last 11 years, WNV has spread throughout the Americas with the imminent risk of its introduction in Brazil. METHODS: Envelope protein domain III of WNV (rDIII) was bacterially expressed and purified. An enzyme-linked immunosorbent assay with WNV rDIII antigen was standardized against mouse immune fluids (MIAFs) of different flavivirus. RESULTS: WNV rDIII reacted strongly with St. Louis encephalitis virus (SLEV) MIAF but not with other flaviviruses. CONCLUSIONS: This antigen may be a potentially useful tool for serologic diagnosis and may contribute in future epidemiological surveillance of WNV infections in Brazil.

Development of two potential diagnostic monoclonal antibodies against human cytomegalovirus glycoprotein B

Human cytomegalovirus glycoprotein B (gB) represents a target for diagnosis and treatment in view of the role it plays in virus entry and spread. Nevertheless, to our knowledge, rare detection of a gB antigen has been reported in transplant patients and limited information is available about diagnostic gB monoclonal antibodies (mAbs). Our aim was to develop gB mAbs with diagnostic potential. Hydrophilic gB peptides (ST: amino acids 27-40, SH: amino acids 81-94) of favorable immunogenicity were synthesized and used to immunize BALB/c mice. Two mAbs, named ZJU-FH6 and ZJU-FE6, were generated by the hybridoma technique and limited serial dilution and then characterized by indirect ELISA, Western blotting, immunoprecipitation, and immunohistochemical staining. The mAbs displayed high titers of specific binding affinities for the ST and SH synthetic peptides at an mAb dilution of 1:60,000 and 1:240,000, respectively. Western blotting and immunoprecipitation indicated that these mAbs recognized both denatured and native gB of the Towne and AD169 strains. The mAbs, when used as the primary antibody, showed positive staining in cells infected with both Towne and AD169 strains. The mAbs were then tested on patients submitted to allogeneic hematopoietic stem cell transplantation. The gB antigen positivity rates of the patients tested using ZJU-FH6 and ZJU-FE6 were 62.0 and 63.0%, respectively. The gB antigen showed a significant correlation with the level of pp65 antigen in peripheral blood leukocytes. In conclusion, two potential diagnostic gB mAbs were developed and were shown to be capable of recognizing gB in peripheral blood leukocytes in a reliable manner.

Obtención y evaluación preliminar de un virus canarypox recombinante como candidato a vacuna antirrábica / Development and preliminary assessment of a recombinant canarypox virus as an antirabic vaccine candidate

En la Argentina, la rabia está circunscripta a algunas provincias del norte. La disponibilidad de nuevas vacunas que eliminen la manipulación del virus rábico y que permitan el control de la enfermedad es de importancia estratégica nacional y regional. Las vacunas basadas en poxvirus recombinantes se han utilizado con éxito como vacunas antirrábicas a nivel mundial. SI bien estos sistemas no están disponibles comercialmente, la plataforma de obtención de virus canarypox (CNPV) recombinantes ya ha sido implementada en nuestro laboratorio. El objetivo de este trabajo fue obtener y evaluar un candidato a vacuna antirrábica basado en CNPV recombinantes que expresan la glicoproteína G (RG) del virus rábico (RV). Se construyó un virus recombinante que expresa la secuencia codificante de RG (CNPV-RG). La inoculación de ratones con este virus indujo altos títulos de anticuerpos seroneutralizantes de RV (3,58 y 9,76 Ul/ml después de una o dos inmunizaciones, respectivamente) y protegió al 78 % de los animales desafiados intracerebralmente con RV. Además, se determinó que el CNPV-RG posee una potencia relativa de 3,5 Ul/ml. Los resultados obtenidos constituyen la primera etapa en la evaluación del CNPV-RG como candidato a vacuna antirrábica. Se requerirán nuevos ensayos para confirmar su utilidad en especies de interés veterinario.

In Argentina, rabies is limited to some northern provinces. Availability of new vaccines abolishing the handling of the rabies virus and allowing disease control has regional and national strategic importance. Vaccines based on recombinant poxviruses have been successfully used as antirabic vaccines worldwide. Although these systems are not commercially available, the platform to obtain recombinant canarypox viruses (CNPV) has been previously set up in our laboratory. The aim of this work was the development and evaluation of an antirabic vaccine candidate based on recombinant CNPV expressing the rabies virus (RV) glycoprotein G (RG). A recombinant virus (CNPV-RG) expressing the RG coding sequence was designed. Inoculation of mice with this virus induced high RV seroneutralizing antibodies (3.58 and 9.76 lU/ml after 1 or 2 immunizations, respectively) and protected 78% of intracerebrally RV-challenged animals. In addition, it was determined that CNPV-RG has a relative potency of 3.5 lU/ml. The obtained results constituted the first stage of CNPV-RG evaluation as antirabic vaccine candidate. Further assays will be necessary to confirm its utility in species of veterinary Interest.

Interaction between human cytomegalovirus UL136 protein and ATP1B1 protein

Interplay between the host and human cytomegalovirus (HCMV) has a pivotal role in the outcome of infection. A region (referred to as UL/b’) present in the Toledo strain of HCMV and low passage clinical isolates contains 19 additional genes, which are absent in the highly passaged laboratory strain AD169. Products of the UL/b’ genes may determine the manifestations of HCMV infection in vivo. However, little is known about the host factors, which interact with UL/b’ proteins. This study was conducted to investigate the function of the HCMV UL136 protein. By yeast two-hybrid screening, the β1 subunit of the host Na+/K+-ATPase (ATP1B1) was identified to be a candidate protein, which interacts with the HCMV UL136 protein. The interaction was further evaluated both in vitro by pull-down assay and in vivo by immunofluorescent co-localization. The results showed that the UL136 protein can interact with ATP1B1 in vitro. Co-localization of UL136-EGFP and ATP1B1-DsRed in cell membranes suggests that ATP1B1 was a partner of the UL136 protein. It can be proposed that the HCMV UL136 protein may have important roles in processes such as cell-to-cell spread, and in maintaining cell osmotic pressure and intracellular ion homeostasis during HCMV infection.

Progress with schistosome transgenesis

Genome sequences for Schistosoma japonicum and Schistosoma mansoni are now available. The schistosome genome encodes ~13,000 protein encoding genes for which the function of only a minority is understood. There is a valuable role for transgenesis in functional genomic investigations of these new schistosome gene sequences. In gain-of-function approaches, transgenesis can lead to integration of transgenes into the schistosome genome which can facilitate insertional mutagenesis screens. By contrast, transgene driven, vector-based RNA interference (RNAi) offers powerful loss-of-function manipulations. Our laboratory has focused on development of tools to facilitate schistosome transgenesis. We have investigated the utility of retroviruses and transposons to transduce schistosomes. Vesicular stomatitis virus glycoprotein (VSVG) pseudotyped murine leukemia virus (MLV) can transduce developmental stages of S. mansoni including eggs. We have also observed that the piggyBac transposon is transpositionally active in schistosomes. Approaches with both VSVG-MLV and piggyBac have resulted in somatic transgenesis and have lead to integration of active reporter transgenes into schistosome chromosomes. These findings provided the first reports of integration of reporter transgenes into schistosome chromosomes. Experience with these systems is reviewed herewith, along with findings with transgene mediated RNAi and germ line transgenesis, in addition to pioneering and earlier reports of gene manipulation for schistosomes.