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Viral Particles (viral + particle)
Selected AbstractsFatal HHV6 infection in an immunocompromised patient presenting with skin involvementJOURNAL OF CUTANEOUS PATHOLOGY, Issue 2 2010Anjela Galan Infection with human herpesvirus-6 (HHV6) has a broad distribution in the human population, with a seroprevalence approaching 100% worldwide. Primary infection takes place during childhood, after which the virus remains latent mostly in lymphocytes and monocytes at various sites. Immunosuppression can result in viral reactivation, associated with clinical sequelae and even death. We report a case of a disseminated HHV6 infection in a 53-year-old patient, who was immunocompromised after allogeneic bone marrow transplant treatment for acute lymphocytic leukemia. Initially, he presented with a macular eruption of the skin, followed by involvement of other sites. Histopathologic analysis of skin biopsies revealed superficial perivascular large atypical mononuclear cells with intranuclear and intracytoplasmic inclusions. Most affected cells labeled with antibodies to CD3 and CD43 as lymphocytes, and some labeled with CD68 as macrophages. Polymerase chain reaction (PCR) studies of the blood, skin, liver, colon, cerebrospinal fluid and brain were positive for HHV6 virus. Additionally, the serologic titers for HHV6 were high. Viral particles were also detected by electron microscopy (EM) in the colon. Although rare, HHV6 virus may be an important pathogen in immunocompromised patients, and may present initially in the skin. Awareness of this infection is critical to diagnosis in acute settings. Galan A, McNiff JM, Nam Choi J and Lazova R. Fatal HHV6 infection in an immunocompromised patient presenting with skin involvement. [source] Viral interactions with the cytoskeleton: a hitchhiker's guide to the cellCELLULAR MICROBIOLOGY, Issue 3 2006Kerstin Radtke Summary The actin and microtubule cytoskeleton play important roles in the life cycle of every virus. During attachment, internalization, endocytosis, nuclear targeting, transcription, replication, transport of progeny subviral particles, assembly, exocytosis, or cell-to-cell spread, viruses make use of different cellular cues and signals to enlist the cytoskeleton for their mission. Viruses induce rearrangements of cytoskeletal filaments so that they can utilize them as tracks or shove them aside when they represent barriers. Viral particles recruit molecular motors in order to hitchhike rides to different subcellular sites which provide the proper molecular environment for uncoating, replicating and packaging viral genomes. Interactions between subviral components and cytoskeletal tracks also help to orchestrate virus assembly, release and efficient cell-to-cell spread. There is probably not a single virus that does not use cytoskeletal and motor functions in its life cycle. Being well informed intracellular passengers, viruses provide us with unique tools to decipher how a particular cargo recruits one or several motors, how these are activated or tuned down depending on transport needs, and how cargoes switch from actin tracks to microtubules to nuclear pores and back. [source] Serum amyloid A has antiviral activity against hepatitis C virus by inhibiting virus entry in a cell culture system,HEPATOLOGY, Issue 6 2006Muriel Lavie Serum amyloid A (SAA) is an acute phase protein produced by the liver. SAA concentration increases markedly in the serum following inflammation and infection. Large increases in SAA concentration during the acute phase response suggest that SAA has a beneficial role in host defense. This study sought to determine the effect of SAA on hepatitis C virus (HCV) infectivity using retroviral particles pseudotyped with HCV envelope glycoproteins (HCVpp) and the recently developed cell culture system for HCV (HCVcc). SAA inhibited HCVpp and HCVcc infection in a dose-dependent manner by affecting an early step of the virus life cycle. Further characterization with HCVpp indicated that SAA blocks virus entry by interacting with the viral particle. In addition, the antiviral activity of SAA was strongly reduced when high-density lipoproteins (HDL) were coincubated with SAA. However, HDL had only a slight effect on the antiviral activity of SAA when HCVpp was first preincubated with SAA. Furthermore, analyses of SAA in sera of chronic HCV patients revealed the presence of variable levels of SAA with abnormally elevated concentrations in some cases. However, no obvious clinical correlation was found between SAA levels and HCV viral loads. In conclusion, our data demonstrate an antiviral activity for SAA and suggest a tight relationship between SAA and HDL in modulating HCV infectivity. (HEPATOLOGY 2006;44:1626,1634.) [source] Purification, crystallization and preliminary X-ray analysis of Triatoma virus (TrV) from Triatoma infestansACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2004Gabriela S. Rozas-Dennis Triatoma virus (TrV) is a viral pathogen of the blood-sucking reduviid bug Triatoma infestans, the most important vector of American human trypanosomiasis (Chagas' disease). TrV has been putatively classified as a member of the Cripavirus genus (type cricket paralysis virus) in the Dicistroviridae family. This work describes the purification of TrV particles from infected T. infestans and their crystallization and preliminary crystallographic analyses. Two different crystal forms, rhombohedral and orthorhombic, were obtained at room temperature by the hanging-drop vapour-diffusion technique using polyethylene glycol and polyethylene glycol monomethylether as precipitants. The rhombohedral crystals have unit-cell parameters a = b = 306.6, c = 788.4,Å (hexagonal setting), diffract to 3.2,Å resolution and contain one-third of the viral particle per asymmetric unit. The orthorhombic crystals have cell parameters a = 336, b = 351, c = 332,Å, diffract to about 2.5,Å resolution, and contain one-half of a virus particle in the asymmetric unit. A complete diffraction data set has been collected to 3.2,Å resolution, using synchrotron radiation, from a single rhombohedral crystal under cryogenic conditions. [source] The effects of exogenous p53 overexpression on HPV-immortalized and carcinogen transformed oral keratinocytesCANCER, Issue 1 2002George H. Yoo M.D. Abstract BACKGROUND Overexpression of p53 in head and neck carcinoma cells has demonstrated tumor growth suppression using in vitro and in vivo models. The effects of exogenous overexpression of wild-type p53 on human papilloma virus (HPV),immortalized and carcinogen transformed oral keratinocytes were determined. METHODS The p53 gene was overexpressed in IHGK (immortalized human gingival keratinocyte), IHGKN [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, (NNK)]-carcinogen transformed keratinocytes, and two head and neck squamous carcinoma (HNSCC) cell lines, HN30 and HN12. The transfection efficiency, growth suppression, and inhibition of the cell cycle along with the induction of apoptosis were measured. RESULTS Transfections with adenoviruses were more efficient for IHGK cells than for IHGKN, HN12, and HN30 cells. Inhibition of proliferation in all cell lines was proportional to the viral particle to cell (VPC) ratios. IHGK cells were more sensitive to p53 than IHGKN cells. HN12 cells were more suppressed than HN30 cells. HN12 were the most suppressed at 72 hours whereas HN30 cells were most suppressed at 24 hours. Expression of exogenous p53-induced G1 cell cycle arrest and p21 expression as VPC ratios increased in IHGK and IHGKN cell lines. Apoptosis also was induced in these cells by p53 as VPC increased. IHGK cells were more sensitive to p53-induced growth inhibition, cell cycle regulation, p21 expression and apoptosis than IHGKN cells. HN12 (mutated p53) cells were more sensitive to p53 overexpression than HN30 (wild-type p53) cells. Gene transfer and expression of exogenous p53 by using Ad-p53 demonstrates suppressive effects on HPV immortalized and carcinogen transformed oral keratinocytes. CONCLUSIONS Cell cycle regulation by gene transfer is feasible in immortalized oral keratinocytes. Carcinogen transformed cells are less susceptible to the effects of p53 overexpression. Expression of exogenous p53 through p53 gene transfer can suppress HPV immortalization and carcinogen transformation in oral keratinocytes. The sensitivity of HNSCC cell lines to p53-induced cell cycle regulation and apoptosis is variable and dependent on the cell line and duration of exposure. In vitro results using p53 gene transfer must be validated in clinical studies with patients at risk for HNSCC. Cancer 2002;94:159,66. © 2002 American Cancer Society. [source] Maternal environment affects endogenous virus induction in the offspring of type 1 diabetes model non-obese diabetic miceCONGENITAL ANOMALIES, Issue 3 2005Yukiko Kagohashi ABSTRACT Type 1 diabetes results from the destruction of pancreatic b-cells (insulitis). It is a multifactorial disease involving genetic and environmental factors, including the maternal environment. Viruses have also been implicated in the pathogenesis of human type 1 diabetes as well as in its model non-obese diabetic (NOD) mice during the perinatal period, as endogenous viruses and/or as infectious agents vertically transmitted from mothers. However, the role of virus as genetic or environmental factor and its interaction with other maternal factors remain unclear. In a series of experiments, we transplanted preimplantation-stage NOD embryos into the uterus of recipient Institute of Cancer Research (ICR) mice, which are without diabetic genetic predisposition, and NOD mice, which did not exhibit overt diabetes during the experiment, and designated offspring as NOD/ICR and NOD/NOD, respectively. We previously observed that NOD/ICR offspring developed insulitis significantly earlier than NOD/NOD offspring. To assess the role of viruses in the development of insulitis, we examined the appearance of viral particles and expression of retroviruses between NOD/ICR and NOD/NOD. NOD/ICR showed earlier expression of env region of the xenotropic type C retrovirus by polymerase chain reaction analysis than NOD/NOD, while the retrovirus-like particles were observed in the islet b-cells similarly in both groups by electron microscopy. Serum corticosterone level, which is suggested to enhance retroviral induction, was significantly higher in the ICR than in the NOD surrogate mothers. These findings suggest that the observed virus is endogenous and that maternal environmental factors, including hormone levels, affect the induction of endogenous viruses and cause the earlier onset of insulitis. [source] The study of cytopathological aspects induced by human cytomegalovirus infectionDIAGNOSTIC CYTOPATHOLOGY, Issue 5 2004B.S., C.M.I.A.C., Takako Takeuchi C.T. Abstract In cytological examination, human cytomegalovirus (HCMV) infection can not be implied unless typical HCMV-infected cells like owl's-eye cells are present. However, such cells are not always observed in HCMV-infection cases. The aim of our study is to establish the cytopathological features induced by HCMV. In vitro transfection and fluorescence in situ hybridization (FISH) were performed on human embryo lung (HEL) cells. Marked cellular aggregation was observed at 6-hr postinfection (hpi). Multinucleated cells, giant cells, and, particularly, small vacuoles were present in the nuclei or cytoplasm before the appearance of inclusion bodies. However, molding and ground glass in nuclei were absent. Cell clusters displayed round cytoplasm, dispersed later, and showed anisocytosis. All features occurred before 48 hpi when the owl's-eye cell appeared. In FISH, the positive signal highlighted viral particles that became predominant and localized in nuclei. These cytological aspects are dependent on viral replication and contribute to the cytological detection of HCMV infection. Diagn. Cytopathol. 2004;31:289,293. © 2004 Wiley-Liss, Inc. [source] Endothelial-Independent Prevention of High Blood Pressure in L-Name-Treated Rats by Angiotensin II type I Receptor Antisense Gene TherapyEXPERIMENTAL PHYSIOLOGY, Issue 4 2003Phyllis Y. Reaves It has previously been established that a single systemic administration of retroviral vector containing angiotensin II type I receptor antisense (AT1R-AS) in the neonatal spontaneously hypertensive rat (SHR) prevents development of hypertension, and in addition cardiac hypertrophy and endothelial dysfunction. However, these studies could not determine whether the effects of AT1R-AS on high blood pressure (BP) and endothelial function were independent. Angiotensin receptor blockers have been shown to reduce BP in the L-NAME (N , -nitro-L-arginine methyl ester hydrochloride)-induced rat model of hypertension. Our objective in the present study was to use the L-NAME model of hypertension to determine whether AT1R-AS treatment would lower high BP and attenuate cardiac hypertrophy under conditions of permanent endothelial damage. A single bolus of LNSV-AT1R-AS viral particles in neonatal Wistar-Kyoto (WKY) rats was without affect on basal BP. Efficacy of the transgene incorporation was assessed by observing a significant reduction in angiotensin-induced dipsogenic response in the AT1R-AS-treated animals. Introduction of L-NAME in the drinking water for 10 weeks resulted in the establishment of hypertension only in the WKY rats treated with vector alone. These hypertensive (BP, 179 ± 4 mmHg) animals showed a 17% increase in heart weight/body weight ratio and a 60% reduction in ACh-induced vasorelaxation in phenylephrine-preconstricted arteries. The L-NAME-induced high BP and cardiac hypertrophy were attenuated in rats expressing AT1R-AS. However, endothelial dysfunction could not be prevented with the antisense therapy. These observations demonstrate that attenuation of endothelial dysfunction is not a prerequisite for the antihypertensive effects of AT1R-AS treatment. [source] A Three-Dimensional and Sensitive Bioassay Based on Nanostructured Quartz Combined with Viral NanoparticlesADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Jong-Hwan Lee Abstract An effective mask-free method for fabricating high-aspect-ratio pillarlike nanostructures over a large area of a quartz surface via a simple O2 and CF4 two-step reactive ion etching (RIE) procedure is developed. The nanostructured quartz surfaces are successfully combined with the engineered viral particles derived from hepatitis B virus capsid, yielding a novel 3D assay system with attomolar sensitivity, which has great potential for use in sensitive and early detection of various disease markers. [source] Cover Picture: Assembly of Wiseana Iridovirus: Viruses for Colloidal Photonic Crystals (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 8 2006Mater. Abstract Assembly of colloids is a versatile tool for micro- and nanofabrication. Natural and artificially engineered viruses offer the opportunity to expand the functionality and versatility of such assemblies. The cover shows optically iridescent, thin polycrystalline arrays (background) as well as bulk pellets (inset right) that exhibit reversible hydration-dependent reflection spectra, as reported by Vaia and co-workers on p.,1086. The films and pellets were created in vitro with classical colloid-assembly techniques from Wiseana iridescent virus (inset, center) harvested from infected Wiseana spp larvae (inset, left). In,vitro assembly of Wiseana iridescent virus (WIV) yields iridescent pellets and films with structural color more vivid than in the native insect. WIV is icosahedral in shape, 140,nm in diameter, with 30,nm long fibrils attached to the outer surface, and exhibits a surface charge ca.,1/6th that of a comparable polymer colloid. The low surface charge and tethered chains on the virus surface allow the facile modification of the interparticle distance. Directed sedimentation yields predominantly an amorphous liquid-like packing of the virus. Such samples exhibit a broad reflection band that is angle independent and for which the broad maximum can be reversibly shifted from blue towards red with increased hydration. Slow sedimentation and flow-assisted assembly methods produce thin films with a polycrystalline morphology that exhibit narrower, more intense reflectivity peaks, which are hydration and angle dependent. This study points toward the potential of viral particles for photonic crystals where their unique structural features (icosahedral symmetry, extreme monodispersity, precise surface functionalization, and tethered surface chains of low surface-charge density) may lead to superior control of optical properties of their assembled arrays. [source] Novel mechanism of antibodies to hepatitis B virus in blocking viral particle release from cells,HEPATOLOGY, Issue 3 2010Avidan U. Neumann Antibodies are thought to exert antiviral activities by blocking viral entry into cells and/or accelerating viral clearance from circulation. In particular, antibodies to hepatitis B virus (HBV) surface antigen (HBsAg) confer protection, by binding circulating virus. Here, we used mathematical modeling to gain information about viral dynamics during and after single or multiple infusions of a combination of two human monoclonal anti-HBs (HepeX-B) antibodies in patients with chronic hepatitis B. The antibody HBV-17 recognizes a conformational epitope, whereas antibody HBV-19 recognizes a linear epitope on the HBsAg. The kinetic profiles of the decline of serum HBV DNA and HBsAg revealed partial blocking of virion release from infected cells as a new antiviral mechanism, in addition to acceleration of HBV clearance from the circulation. We then replicated this approach in vitro, using cells secreting HBsAg, and compared the prediction of the mathematical modeling obtained from the in vivo kinetics. In vitro, HepeX-B treatment of HBsAg-producing cells showed cellular uptake of antibodies, resulting in intracellular accumulation of viral particles. Blocking of HBsAg secretion also continued after HepeX-B was removed from the cell culture supernatants. Conclusion: These results identify a novel antiviral mechanism of antibodies to HBsAg (anti-HBs) involving prolonged blocking of the HBV and HBsAg subviral particles release from infected cells. This may have implications in designing new therapies for patients with chronic HBV infection and may also be relevant in other viral infections. (HEPATOLOGY 2010;) [source] Interferon-inducible expression of APOBEC3 editing enzymes in human hepatocytes and inhibition of hepatitis B virus replication,HEPATOLOGY, Issue 6 2006Marianne Bonvin Hypermutations in hepatitis B virus (HBV) DNA by APOBEC3 cytidine deaminases have been detected in vitro and in vivo, and APOBEC3G (A3G) and APOBEC3F (A3F) have been shown to inhibit the replication of HBV in vitro, but the presumably low or even absent hepatic expression of these enzymes has raised the question as to their physiological impact on HBV replication. We show that normal human liver expresses the mRNAs of APOBEC3B (A3B), APOBEC3C (A3C), A3F, and A3G. In primary human hepatocytes, interferon alpha (IFN-,) stimulated the expression of these cytidine deaminases up to 14-fold, and the mRNAs of A3G, A3F, and A3B reached expression levels of 10%, 3%, and 3%, respectively, relative to GAPDH mRNA abundance. On transfection, the full-length protein A3BL inhibited HBV replication in vitro as efficiently as A3G or A3F, whereas the truncated splice variant A3BS and A3C had no effect. A3BL and A3BS were detected predominantly in the nucleus of uninfected cells; however, in HBV-expressing cells both proteins were found also in the cytoplasm and were associated with HBV viral particles, similarly to A3G and A3F. Moreover, A3G, A3F, and A3BL, but not A3BS, induced extensive G-to-A hypermutations in a fraction of the replicated HBV genomes. In conclusion, the editing enzymes A3BL, A3F, and most markedly A3G, which are expressed in liver and up-regulated by IFN-, in hepatocytes, are candidates to contribute to the noncytolytic clearance of HBV. (HEPATOLOGY 2006;43:1364,1374.) [source] Apoptotic-like morphology is associated with annual synchronized death in kleptoplastic sea slugs (Elysia chlorotica)INVERTEBRATE BIOLOGY, Issue 2 2003William L. Mondy Abstract. Certain digestive cells of the opisthobranch mollusc, Elysia chlorotica, contain functional chloroplasts which they steal from the filamentous alga, Vaucheria litorea. The adult portion of the life cycle of the slug lasts for ,10 months and is completely synchronized among individuals. All the adults die each year within a few weeks of each other. We have examined the microscopic morphology of the slugs near the end of the life cycle. Light microscopy demonstrated an absence of chloroplasts in most of the digestive epithelial cells, the appearance of many crypt cells containing residual bodies and an invasion of the blood sinuses by neoplastic morula-like cells as the animals die. Electron microscopy revealed a degeneration of the digestive diverticulum which had several morphological characteristics in common with apoptosis: expansion of the endoplasmic reticulum and Golgi apparatus, DNA fragmentation, formation of primary lysosomes, and condensation of chromatin. These are followed by fragmentation of the nucleus and cytoplasm into autosomes merging to form a large central autolysosome. In addition in the aging slugs, the plastids begin to degenerate until none were left in the digestive epithelial cells and the central autolysosome contained numerous viral particles. [source] Extra small virus-like particles (XSV) and nodavirus associated with whitish muscle disease in the giant freshwater prawn, Macrobrachium rosenbergiiJOURNAL OF FISH DISEASES, Issue 9 2003D Qian Abstract A disease of Macrobrachium rosenbergii, the giant freshwater prawn, farmed in China was recently recorded in Zhejiang, Jiangsu, Shanghai, Guangxi and Guangdong provinces. The clinical sign of the disease, which develops in post-larvae (PL), is a whitish appearance of the muscles, particularly noticeable in the abdomen. Mortalities may reach 100% in some hatcheries. Investigations by transmission electron microscopy after negative staining of diseased PL homogenates showed the presence of two types of viral particles: one, unenveloped, icosahedral in shape, 26,27 nm in diameter, the second, much smaller, about 14,16 nm in diameter, designated extra small virus particle (XSV). The large virus has a genome with two pieces of ssRNA (RNA-1 and RNA-2), of 3 and 1.2 kb, respectively. Hybridization tests confirmed that this large virus is closely related to M. rosenbergii nodavirus (MrNV) which was isolated from diseased prawns in a hatchery in the French West Indies. Its very small size and hypothesized biochemical and biological characteristics suggest XSV is a new type of crustacean virus. As XSV has always been found associated with the larger virus (nodavirus) and is located in muscle and connective cells of diseased animals, it could be an autonomous virus, a helper-type virus or a satellite-like virus. [source] Development of real-time detection direct test for hepatitis B virus and comparison with two commercial tests using the WHO international standardJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 11 2003MOTOKAZU MUKAIDE Abstract Aims:, A highly reproducible and sensitive hepatitis B virus real-time detection direct (HBV RTD-direct) test using DNA extraction by magnetic beads coated with polyclonal anti-HBsAg, followed by the real-time detection polymerase chain reaction (PCR) method, was developed for the detection of HBV DNA. Methods:, The HBV DNA could be extracted from the HBsAg positive viral particles without resulting in viral DNA fragmentation. The HBV RTD-direct test was validated using a serial dilution panel of the WHO standard HBV DNA 97/746 I. Results:, The test had a dynamic range of 0.7,8.0 log10 international units (IU) per mL and the results were shown to be comparable to those obtained with two commercially available tests: the HBV DNA transcription-mediated amplification-hybridization protection assay and the Amplicor HBV Monitor test. In addition, the HBV RTD-direct test, based on magnetic extraction, successfully eliminated PCR inhibitors in clinical specimens. Conclusion:, We conclude that the HBV RTD-direct test is an excellent alternative for monitoring patients undergoing antiviral treatment or for screening various clinical specimens. [source] Transgenic mice replicating hepatitis B virus but lacking expression of the major HBsAg,JOURNAL OF MEDICAL VIROLOGY, Issue 4 2008Leonie Halverscheid Abstract Hepatitis B Virus (HBV) transgenic mice replicating the viral genome at high level but lacking expression of the small envelope protein (HBsAg) have been produced using a terminally redundant viral DNA construct (HBV 1.4). The generation of viable infectious progeny was dependent on sex and age of mice. Viral mRNA was abundant in liver and kidneys and at low levels in other organs of the mice. No viral particles or HBV envelope proteins could be detected in sera of mice. Despite expression of non-secreted LHBs and MHBs proteins in the liver, there was no accumulation of viral particles in the endoplasmic reticulum of hepatocytes and no necroinflammatory hepatitis was observed. Therefore, these mice represent an excellent model for studies of the role of HBsAg in viral assembly, antiviral immune responses, the further understanding of HBV immunopathogenesis, and the development of antiviral vaccines. J. Med. Virol. 80:583,590, 2008. © 2008 Wiley-Liss, Inc. [source] Do G protein-coupled receptors expressed in human lingual epithelium interact with HPV11?JOURNAL OF MEDICAL VIROLOGY, Issue 10 2007Lukasz Durzy Abstract Human papillomaviruses infect epithelia but little is known about the nature of cell surface receptors interacting with the viral particles. It has been proposed that glycosaminoglycans and integrins may be involved in the attachment process. In the present study, the putative interactions of virus-like particles of human papillomavirus type 11 (HPV11), which present a tropism for nasopharyngeal epithelia, with olfactory and taste receptors expressed in the human lingual epithelium were studied. The L1 protein of HPV11 was produced in insect cells. The presence of L1 virus-like particles was analyzed by ELISA using monoclonal antibodies specific for full-size particles and by electron microscopy. Using immunofluorescence, it was observed that virus-like particles interacted with taste buds from murine tongue, with the tagged human olfactory receptor hJCG5 expressed in HEK-293 but not with the tagged taste receptor hT2R4. This therefore suggests that hJCG5 may be involved in the adsorption process of HPV11 to lingual epithelium serving as a so-called "adsorption-adhesive molecule." J. Med. Virol. 79:1545,1554, 2007. © Wiley-Liss, Inc. [source] Lack of susceptibility of Chacma baboons (Papio ursinus orientalis) to hepatitis C virus infectionJOURNAL OF MEDICAL VIROLOGY, Issue 4 2002N.P. Sithebe Abstract The main reason to ascertain whether baboons are susceptible to infection with hepatitis C virus (HCV) is the need to replace chimpanzees, which are endangered, as an animal model for undertaking research into the biology and host,virus interactions of HCV, and for developing a vaccine against this virus. A second reason is that baboons are a possible source of xenografts for human liver transplantation. We inoculated serum containing HCV into four Chacma baboons and monitored them for 52 weeks for evidence of infection. Serum was tested for antibody to HCV, HCV RNA, and aminotransferase concentrations at 2-week intervals for 26 weeks and thereafter at 4-week intervals. Liver tissue was examined at 28 and 52 weeks for histopathological changes and viral RNA, and at 52 weeks for viral particles using electron microscopy. Reverse transcription-polymerase chain reaction assay was used to detect HCV RNA, and the results were confirmed by Southern hybridization. Serum aminotransferase concentrations remained within the normal range and liver histology was normal during the follow-up period. Passive transmission of anti-HCV to the baboons was observed during the first 4 weeks. HCV RNA was not detectable in any serum or liver sample and electron microscopy failed to reveal viral particles in liver tissue. In conclusion, we did not find Chacma baboons to be susceptible to infection with HCV, although we cannot deny that in an immunosuppressed liver transplant recipient, infection of a baboon xenograft might occur. Another animal model for HCV infection must be sought. J. Med. Virol. 66:468,471, 2002. © 2002 Wiley-Liss, Inc. [source] Biological and Molecular Characterization of Melon-Infecting Kyuri Green Mottle Mosaic Virus in IndonesiaJOURNAL OF PHYTOPATHOLOGY, Issue 10 2005B. S. Daryono Abstract Melon (Cucumis melo L.) plants showing fruit deformation and mosaic symptoms were found in Java, Indonesia, in 2001. Leaf dips of the symptomatic melon tissue revealed rod-shaped viral particles 300 × 18 nm in size. Biological and serological data described in this study indicate that the virus belonged to the genus tobamovirus and was related to the kyuri green mottle mosaic virus (KGMMV). The genome of the virus has been completely sequenced, consisting of 6512 nucleotides and was compared in detail with KGMMV-C1 and KGMMV-Y. The sequence of their 5,- and 3,- non-coding regions (NCRs) were 91% and 94% identical to KGMMV-C1, and only 82% and 95% identical to KGMMV-Y respectively. The amino acid sequence of the shorter and longer RNA replicase components, movement protein and coat protein were 94%, 91%, 95% and 94% identical to KGMMV-C1 and 93%, 89%, 91% and 85% identical of KGMMV-Y respectively. The results from phylogenetic analysis of the coding regions revealed that KGMMV-YM is a new strain of KGMMV. This is the first report of the complete nucleotide sequence and analysis of genome organization for KGMMV isolated in anywhere in South-East Asia. [source] Presence of HCV-RNA after ultracentrifugation of serum samples during the follow-up of chronic hepatitis C patients with a sustained virological response may predict reactivation of hepatitis C virus infectionALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2009I. CASTILLO Summary Background, Concentration of viral particles by ultracentrifugation of serum prior to PCR allows detection of hepatitis C virus (HCV) RNA in patients with undetectable viral RNA by conventional PCR assays. Aim, To analyse if HCV-RNA is detected after serum ultracentrifugation in chronic hepatitis C patients with a sustained virological response to antiviral therapy (defined as serum HCV-RNA negativity by conventional assays 6 months after the end of therapy). Methods, HCV-RNA was tested using real-time PCR in ultracentrifuged sera collected during the post-treatment follow-up (mean: 42 ± 27 months) in 57 sustained virological responders (SVR). Results, After serum ultracentrifugation, HCV-RNA was detected on at least one occasion during the follow-up in 29/57 (51%) SVR. Thirteen (23%) of these 57 SVR suffered a reactivation 18 ± 8 months after the end of therapy (reappearance of serum HCV-RNA detectable by conventional assays). Among reactivated patients, 11/13 (85%) had HCV-RNA in ultracentrifuged serum samples (detectable 10 ± 5 months before reactivation), while HCV-RNA was positive after ultracentrifugation in 18/44 (41%) long-term SVR (P = 0.01). Persistence of detectable HCV-RNA after serum ultracentrifugation was associated with reactivation (P = 0.001). Conclusions, Serum ultracentrifugation prior to PCR allows detection of HCV-RNA in SVR and its persistence may predict late reactivation. [source] Challenges and strategies: The immune responses in gene therapyMEDICINAL RESEARCH REVIEWS, Issue 6 2004Hai-sheng Zhou Abstract The host immune responses, including T lymphocytes mediated immune response and humoral immune responses are the important parts of the challenges in gene therapy. There are some potential immunostimulants in gene delivery systems, such as viral and non-viral vectors. Viral gene products, transgene products, viral proteins derived from viral particles required by dead-end infection, and CpG DNA in plasmid may play important roles in inducing the host immune responses when foreign genes are transferred into the targeted tissues. The immune responses should lead to many problems in gene therapy: transient expression of therapeutic gene, non-efficient re-administration of the same vectors, and severe side-effects in clinical trials. Although RNAi may act as gene therapeutic agent for suppression of specific gene expression, little attention has been given to the potential non-specific effects that might be induced. It was reported that small interfering RNAs (siRNAs) can induce the host interferon response following transfected to mammalian cells. Facing these challenges, a number of studies have been focused on taking measures to solve them, such as immunosuppression, selection of different administration routes and dose of the vectors, using the tissue-specific promoters and modifying the vectors. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 6, 748,761, 2004 [source] Immobilization of diverse foreign proteins in viral polyhedra and potential application for protein microarraysPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 1 2006Keiko Ikeda Abstract Cypoviruses are insect viruses that produce a cytoplasmic crystalline particle called the polyhedron in which progeny virions are occluded. The virion structural protein, VP3, is implicated in the occlusion of viral particles into polyhedra. In this study, we determined the amino acid sequence of VP3 required for occlusion of viral particles into polyhedra and proposed that this sequence could be used as an immobilization signal to direct the stable incorporation of foreign proteins into polyhedra. A large-scale survey revealed that the immobilization signal could, in fact, direct the incorporation of a variety of human proteins into polyhedra. Immune reactivity and protein,protein interactions were detected on the surface of polyhedra containing immobilized foreign proteins, and these particles were shown to be highly stabilized against dehydration. We showed that these particles could be arrayed onto a glass slide by standard spotting and laser manipulation methods. Thus, this approach is well suited for protein expression, purification, and the development of protein microarrays. [source] Immobilized HIV-1 Tat protein promotes gene transfer via a transactivation-independent mechanism which requires binding of Tat to viral particlesTHE JOURNAL OF GENE MEDICINE, Issue 11 2009Filomena Nappi Abstract Background Retroviral transduction of cells is improved upon virus adsorption onto immobilized fibronectin (FN) fragments. Because HIV-1 Tat possesses the same functional domains that lead to increased transduction efficiency in FN by colocalization of bound virus and cells, we hypothesized that Tat could enhance gene transfer by a similar mechanism. Methods Single-cycle replication retro- or lentivirus carrying green fluorescent protein or cloramphenicol acetyltransferase as reporter genes were added to wells coated with Tat or Tat peptides. Wells were extensively washed to remove unbound virus and levels of transduction were detected by measuring reporter gene expression. Virus adsorption to immobilized Tat was measured using a p24 antigen capture assay. Results Immobilized Tat efficiently binds retro- and lentiviral particles and mediates virus transmission at virus input doses that were otherwise unable to transduce susceptible cells. Virus adsorption to Tat is not mediated by envelope glycoprotein (Env) because immobilized Tat binds and retains vesicular stomatitis virus G (VSV-G) pseudotypes as well as envelope-free particles. HIV-1 Env or VSV-G are required for Tat-assisted transduction, which is abrogated by an antibody blocking the HIV-1 Env,CD4 interaction. Tat-assisted transduction is mediated by the cysteine-rich region of Tat, which is known to be essential for Tat transactivation activity. However, Tat transactivation is not required for Tat-assisted transduction, as indicated by the enhancement of transduction by transactivation-silent Tat mutants. Conclusions Immobilized Tat promotes virus transduction by a transactiva- tion-independent mechanism, which requires binding of virus to Tat. Recombinant Tat or Tat fragments provide a new method to increase efficiency of retro- and lentiviral based gene transfer and gene therapy. Copyright © 2009 John Wiley & Sons, Ltd. [source] Osseous Tissue Engineering With Gene Therapy for Facial Bone Reconstruction,THE LARYNGOSCOPE, Issue 7 2001William H. Lindsey MD Abstract Objective Facial osseous defects remain a major functional and esthetic challenge for the head and neck surgeon. Tissue engineering may provide advantageous alternatives to conventional therapies. The objective of the study was to evaluate the efficacy of gene therapy in the repair of osseous facial defects. Study Design Blinded, controlled, prospective animal experiment. Methods Thirty adult athymic nude rats were divided into five groups of six animals. Three groups were used as control subjects. Two groups were treated with 3.75 × 108 viral particles containing recombinant type 5 adenoviral vectors. One group received viruses that coded for ,-galactosidase production, another received viruses that coded for bone morphogenetic protein (BMP-2) production. After 120 days rats were examined at necropsy with precise planimetry, histological analysis of new bone growth, and radio-densitometric analysis of bone thickness. Results Radio-densitometric measurements showed that BMP-2,treated nude athymic rats had significantly enhanced osseous repair compared with control subjects when evaluated by both radio-densitometry and histological examination. Conclusion Gene therapy,treated, immunosuppressed rodents had an enhanced osteoinductive repair of a dorsal osseous nasal defect. [source] Trichodysplasia spinulosa associated with chemotherapy for acute lymphocytic leukaemiaAUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 2 2007Genevieve M Sadler SUMMARY We report two boys with trichodysplasia spinulosa associated with chemotherapy for acute lymphocytic leukaemia. Trichodysplasia spinulosa is a cutaneous viral infection of immunosuppressed patients that causes abnormal hair follicle maturation. Our patients presented with widespread papules, some extruding a central keratin spicule, which were most prominent on the face. Histopathology demonstrated hair follicles dilated by a proliferation of large eosinophilic cells containing numerous abnormal trichohyaline granules. Electron microscopy in case 1 revealed 30-nm viral particles in the stratum corneum consistent with a papovavirus. In case 1, the eruption persisted despite topical salicyclic acid 4%, ammonium lactate 17.5%, tretinoin 0.05% and oral acitretin. However, it resolved once the patient's immune function returned to normal (total duration of 2 years). In case 2, the eruption spontaneously resolved after 9 months. This case report discusses the characteristic clinicopathological features of trichodysplasia spinulosa and, for the first time, follows the condition's natural history. [source] Tricalcium phosphate nanoparticles enable rapid purification, increase transduction kinetics, and modify the tropism of mammalian virusesBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2009Imke A.J. Dreesen Abstract Adenoviral, adeno-associated viral, and retroviral particles are chosen as gene delivery shuttles in more than 50% of all gene therapy clinical trials. Bulk availability of clinical-grade viral particles and their efficiency to transduce the therapeutic cargo into specific target cells remain the most critical bottlenecks in gene therapy applications to date. Capitalizing on the flame-spray technology for the reproducible economic large-scale production of amorphous tricalcium phosphate nanoparticulate powders (ATCP), we designed a scalable ready-to-use gravity-flow column set-up for the straightforward concentration and purification of transgenic adenoviral, adeno-associated viral, and lentiviral particles. Specific elution buffers enabled rapid release of viral particles from the ATCP matrix of the column and provided high-titer virus preparations in an unsurpassed period of time. The interaction of ATCP with adenoviral, adeno-associated viral, and lentiviral particles in solution increased the transduction kinetics of several mammalian cell lines in culture. The nanoparticles were also able to modify the tropism of murine leukemia virus (MLV) towards transduction of human cells. Based on these findings, we believe that the use of flame-spray tricalcium phosphate nanoparticles will lead to important progress in the development of future gene therapy initiatives. Biotechnol. Bioeng. 2009;102: 1197,1208. © 2008 Wiley Periodicals, Inc. [source] Epstein,Barr virus involvement in the pathogenesis of hydroa vacciniforme: an assessment of seven adult patients with long-term follow-upBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2010L. Verneuil Summary Background, Hydroa vacciniforme (HV) is a chronic papulovesicular photodermatosis of childhood, with some cases persisting through adulthood. In children, the Epstein,Barr virus (EBV) has been detected in typical HV and in HV evolving into natural killer/T-cell lymphoma. No exploration of EBV infection has been performed in adult patients with HV with long-term follow-up. Objectives, To assess EBV infection systematically in blood and in experimentally photoinduced lesions in adult patients with HV. Methods, Repeated tests for EBV DNA blood load using real-time polymerase chain reaction (PCR) and serological EBV tests were performed in seven adult patients with long-term follow-up. Skin samples from phototest-induced lesions and surrounding normal skin were studied using PCR, in situ hybridization and electron microscopy. ZEBRA protein was detected using immunostaining. Thirty-five patients with other photosensitive disorders were included as controls. Results, The EBV DNA blood load was strongly positive in the seven patients with HV and negative in 34 of 35 of the patients with other photosensitive disorders (P < 0·001). The levels were higher in photosensitive patients with HV than in patients with HV in clinical remission. Ultrastructurally, viral particles were detected in lymphocytes and also in keratinocytes in three experimentally phototest-induced lesions; they were not found in the surrounding normal skin. ZEBRA protein was also detected in phototest-induced lesions, but not in the surrounding normal skin. Conclusion, EBV is involved in HV pathogenesis and persists in adult patients with HV. A positive EBV DNA load, specific to HV in the spectrum of photosensitive disorders, might be a useful biomarker in HV. [source] Qualitative and quantitative ultrastructural analysis of the membrane rearrangements induced by coronavirusCELLULAR MICROBIOLOGY, Issue 6 2010Mustafa Ulasli Summary Coronaviruses (CoV) are enveloped positive-strand RNA viruses that induce different membrane rearrangements in infected cells in order to efficiently replicate and assemble. The origin, the protein composition and the function of these structures are not well established. To shed further light on these structures, we have performed a time-course experiment in which the mouse hepatitis virus (MHV)-induced membrane rearrangements were examined qualitatively and quantitatively by (immuno)-electron microscopy. With our approach we were able to confirm the appearance of 6, previously reported, membranous structures during the course of a complete infection cycle. These structures include the well-characterized double-membrane vesicles (DMVs), convoluted membranes (CMs) and virions but also the more enigmatic large virion-containing vacuoles (LVCVs), tubular bodies (TBs) and cubic membrane structures (CMSs). We have characterized the LVCVs, TBs and CMSs, and found that the CoV-induced structures appear in a strict order. By combining these data with quantitative analyses on viral RNA, protein synthesis and virion release, this study generates an integrated molecular and ultrastructural overview of CoV infection. In particular, it provides insights in the role of each CoV-induced structure and reveals that LVCVs are ERGIC/Golgi compartments that expand to accommodate an increasing production of viral particles. [source] Human cytomegalovirus final envelopment on membranes containing both trans -Golgi network and endosomal markersCELLULAR MICROBIOLOGY, Issue 3 2010Victoria Cepeda Summary The human cytomegalovirus (HCMV) has been shown to complete its final envelopment on cytoplasmic membranes prior to its secretion to the extracellular medium. However, the nature of these membranes has not been characterized. It is thought that HCMV acquires its final envelope from the trans -Golgi network (TGN), though we and others have previously reported a role for endocytic membranes. Here we studied the localization of cellular markers in HCMV-infected cells and in isolated viruses. Immunofluorescence staining indicated that HCMV induces the recruitment of TGN and endosomal markers to the virus factory. Immuno-gold labelling of isolated viral particles and electron microscopy demonstrated the incorporation of TGN46, endosomal markers early endosomal antigen 1, annexin I, transferrin receptor and CD63, and the cation-independent mannose 6-phosphate receptor, which traffics between the TGN and endosomes into the viral envelope. Virus immunoprecipitation assays demonstrated that virions containing TGN46 and CD63 were infectious. This study reconciles the apparent controversy regarding the nature of the HCMV assembly site and suggests that HCMV has the ability to generate a novel membrane compartment containing markers for both TGN and endosomes, or that the membranes that HCMV uses for its envelope may be vesicles in transit between the TGN and endosomes. [source] The ESCRT machinery is not required for human cytomegalovirus envelopmentCELLULAR MICROBIOLOGY, Issue 12 2007Alberto Fraile-Ramos Summary The human cytomegalovirus (HCMV) has been proposed to complete its final envelopment on cytoplasmic membranes prior to its release to the extracellular medium. The nature of these membranes and the mechanisms involved in virus envelopment and release are poorly understood. Here we show by immunogold-labelling and electron microscopy that CD63, a marker of multivesicular bodies (MVBs), is incorporated into the viral envelope, supporting the notion that HCMV uses endocytic membranes for its envelopment. We therefore investigated a possible role for the cellular endosomal sorting complex required for transport (ESCRT) machinery in HCMV envelopment. Depletion of tumour suppressor gene 101 and ALIX/AIP1 with small interfering RNAs (siRNAs) in HCMV-infected cells did not affect virus production. In contrast, siRNAs against the vacuolar protein sorting 4 (VPS4) proteins silenced the expression of VPS4A and VPS4B, inhibited the sorting of epidermal growth factor to lysosomes, the formation of HIV Gag-derived virus-like particles and vesicular stomatitis virus infection, but enhanced the number of HCMV viral particles produced. Treatment of infected cells with protease inhibitors also increased viral production. These studies indicate that, in contrast to some enveloped RNA viruses, HCMV does not require the cellular ESCRT machinery to complete its envelopment. [source] | |||||||||||||||||||