Enveloped Viruses (enveloped + viruse)

Distribution by Scientific Domains


Selected Abstracts


Plasmacytoid dendritic cell activation by foot-and-mouth disease virus requires immune complexes

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2006
Laurence Guzylack-Piriou
Abstract Natural IFN-producing cells (NIPC), also called plasmacytoid dendritic cells, represent an essential component of the innate immune defense against infection. Despite this, not much is known about the pathways involved in their activation by non-enveloped viruses. The present study demonstrates that the non-enveloped foot-and-mouth disease virus (FMDV) cannot stimulate IFN-, responses in NIPC, unless complexed with FMDV-specific immunoglobulins. Stimulation of NIPC with such immune complexes employs Fc,RII ligation, leading to strong secretion of IFN-,. In contrast to the stimulation of NIPC by many enveloped viruses, FMDV induction of IFN-, production requires live virus. It is necessary for the virus to initiate its replicative cycle. Moreover, it is an abortive replication, as witnessed by the decrease of dsRNA levels and viral titers with time post infection. Sensitivity of the NIPC stimulation to wortmannin and chloroquin, but not leupeptin, indicates an essential role for the pre-lysosomal stage endosomal compartment. In conclusion, the present study demonstrates that immune complexes provide the means for a non-interferogenic virus to induce IFN-, responses by NIPC. This indicates an important link between NIPC and antibodies in immune responses against non-enveloped viruses such as FMDV. [source]


In vitro effect of oral antiseptics on human immunodeficiency virus-1 and herpes simplex virus type 1

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2001
A. A. M. A. Baqui
Abstract Aim: The antiviral effectiveness of widely used commercial mouthrinses has not been well studied. A project was undertaken to evaluate and compare the in vitro antiviral effectiveness of essential oil-containing mouthrinses (LA & TLA) and chlorhexidine mouthrinses (PX & CHX) on 2 different enveloped viruses, human immunodeficiency virus (HIV-1) and Herpes simplex virus (HSV-1) McIntyre strain. Method: HIV-189.6 (1×105/ml) and HSV-1 (1×106/ml) in RPMI-1640 medium were treated with two commercially available forms of LA & TLA (tartar control LA), and 2 formulations of chlorhexidine [(PX), 0.12% chlorhexidine & (CHX), 0.2% chlorhexidine] for 30 sec. The antiviral effect was estimated by inhibition of the syncytia formation or the cytopathic effect (CPE) for HIV-1 on MT-2 cells and by inhibition of the plaque formation for HSV-1 on Vero cell monolayers. Results: Undiluted LA, TLA, PX and CHX completely inhibited both HIV-189.6 and HSV-1 McIntyre strain. PX and CHX inhibited HIV-1 up to 1:4 dilution, whereas, LA and TLA inhibited HSV-1 up to 1:2 dilution. The antiviral effects of LA and TLA were found to be similar and also the antiviral effect of PX and CHX were also found to be comparable. Conclusions: The methods used in this investigation allow easy and reproducible evaluations of antiviral efficacy. The anti-HIV-1 and anti-HSV-1 effects of LA, TLA, PX and CHX as evidenced in our in vitro study suggest that we should investigate potential in vivo effects during the use of essential oil-containing or chlorhexidine containing products when used by patients as mouthrinses. If the clinical studies confirm the in vitro data, pre-procedural use by clinicians may be beneficial in reducing viral contamination of bio-aerosols during the delivery of dental care. Zusammenfassung Ziel: Die antivirale Effektivität von breit genutzten kommerziellen Mundwässern wurde bisher nicht gut untersucht. Ein Projekt wurde deshalb aufgenommen, um den in vitro antiviralen Effekt von ätherischen Öl enthaltenden Mundwässern (LA & TLA) und Chlorhexidin Mundwässern (PX & CHX) auf 2 unterschiedlich entwickelte Viren, das menschliche Immundefizienz Virus (HIV-1) und das Herpes simplex Virus (HSV-1) McIntyre Stamm zu evaluieren und zu vergleichen. Methoden: HIV-189.6 (1×105/ml) und HSV-1 (1×106/ml) in RPMI-1640 Medium wurden mit 2 kommerziellen Formen von LA & TLA (Tartarkontrolle LA) und 2 Arten von Chlorhexidin [(PX), 0.12% Chlorhexidin & (CHX), 0.2% Chlorhexidin] für 30 Sekunden behandelt. Der antivirale Effekt wurde durch Inhibition der Syncytiumbildung oder des cytopathischen Effektes (CPE) für HIV-1 auf MT-2 Zellen und durch Inhibition der Plaquebildung für HSV-1 auf Vero Zellmonolayers bestimmt. Ergebnisse: Unverdünntes LA, TLA, PX und CHX inhibierte sowohl HIV-189.6 und HSV-1 McIntyre Stamm. PX und CHX inhibierte HIV-1 bis zu einer 1:4 Verdünnung, während LA und TLA HSV-1 bis zu einer 1:2 Verdünnung inhibierte. Die antiviralen Effekte von LA und TLA wurden gleichwertig gefunden und auch der antivirale Effekt von PX und CHX waren vergleichbar. Zusammenfassung: Die genutzten Methoden in dieser Untersuchung erlaubten leicht und reproduzierbar die Evaluation von antiviralen Effekten. Die anti-HIV-1 und anti-HSV-1 Effekte von LA, TLA, PX und CHX, die in unserer in vitro Studie evident waren, suggerieren, daß wir das Potential der in vivo Effekte während des Gebrauches von ätherischen Öl enthaltenden oder Chlorhexidin enthaltenden Produkten untersuchen sollten, wenn die Patienten dies als Mundwässer benutzen. Wenn die klinischen Studien die in vitro Ergebnisse bestätigen, kann der vorherige Gebrauch durch die Kliniker die virale Kontamination von Bioaerosolen während der durchgeführten zahnäztlichen Behandlung reduzieren. Résumé But: L'efficacité antivirale des bains de bouches largement commercialises n'a pas été bien étudiée. Notre projet a évalué et comparé l'efficité antivirale in vitro de bains de bouche aux huiles essentielles (LA et TLA) et à la chlorexhidine (PX et CHX) sur 2 virus à envelopes, le virus de l'immunodéfiscience acquise 1 (HIV1) et la souche McIntyre du virus de l'Herpes simplex de type 1 (HSV1). Méthode: HIV1896 (1×105/ml) et HSV1 (1×106 ml) dans un milieu RPMI-1640 furent traits avec 2 formes disponibles sur le marché de LA et TLA, et 2 formules de chloxhexidine (PX, 0.12% chlorexhidine et CHX, 0.2% chlorexhidine) pendant 30 s. L'effet antiviral fut estimé par l'inhibition de la formation de syncitia ou par l'effet cytopathique (CPE) pour HIV1, sur des cellules MT2 et par l'inhibition de la formation de plaque pour HSV1 sur des monocouches cellulaires Vero. Résultats: CHX, LA, TLA et PX non dilués inhibaient complètement à la fois HIV1896 et la souche McIntyre HSV1. PX et CHX inhibaient HIV1 jusqu'à une dilution par 4 alors que LA et TLA inhibaient HSV1 jusqu'à une dilution par 2. Les effets antiviraux de LA et TLA étaient similaires, et les effets antiviraux de PX et CHX étaient aussi comparables. Conclusions: Les methodes utilisées pour cette recherche permettent une évaluation facile et reproductible de l'efficacité antivirale. Les effets anti-HIV1 et anti-HSV1 de LA, TLA, PX et CHX trouvés ici in vitro suggèrent que nous recherchions des effects potentiels in vivo lors de l'utilisation de produits contenant des huiles essentielles ou de la chlorexhidine utilisés comme bains de bouches par les patients. Si les études cliniques confirment les données in vitro, l'utilisation préclinique par les praticiens pourrait leur être bénéfique en réduisant la contamination virale des bioaérosols lors des soins dentaires. [source]


Arginine facilitates inactivation of enveloped viruses

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2008
Hisashi Yamasaki
Abstract Virus inactivation is a key step for the purification of pharmaceutical proteins derived from recombinant mammalian expression systems and conventionally done using low pH-treatment, which is often harmful to the proteins to be purified. This is particularly true for antibodies, because immunoglobulin proteins undergo conformational changes at acidic pH. We have been developing mild elution solvents using arginine for Protein-A chromatography to minimize the low pH-induced damages on the antibodies. Here we have tested the aqueous solutions containing arginine or butyroyl-arginine at or above pH 4.0 for their effects on virus inactivation, since these solvents are effective above pH 4.0 in elution of bound antibodies from Protein-A columns. When the virus was incubated on ice, 0.1 M sodium citrate was totally ineffective above pH 4.0, but aqueous solutions containing arginine above 0.35 M or butyroyl-arginine above 0.28 M showed extensive virus killing at or even above pH 4.0. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97: 3067,3073, 2008 [source]


Photoinactivation of Sindbis Virus Infectivity Without Inhibition of Membrane Fusion

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2009
Wor Thongthai
Photoinactivation of enveloped viruses is commonly associated with damage to fusion proteins and inhibition of membrane fusion capacity. Here we show that photobleaching of Sindbis virus labeled with the membrane localized dye, R18 (octadecyl rhodamine B) causes a dramatic loss of infectivity without observable changes in low-pH triggered membrane fusion to liposomes. Sindbis labeled with DiI (1,1,-dioctadecyl-3,3,3,,3,-tetramethylindocarbocyanine perchlorate) also maintains low-pH triggered membrane fusion capacity, but in contrast to R18, extensive photobleaching of DiI-labeled virus has little effect on infectivity. Electrophoretic gel analysis suggests no cross-linking of viral fusion proteins following photobleaching of dye-labeled Sindbis. These observations have implications for live-cell, single particle tracking studies of dye-labeled Sindbis virus. Our observations suggest that R18 and DiI have different propensities for spontaneous flip-flop in lipid bilayers. [source]


Endosomal sorting complex required for transport proteins in cancer pathogenesis, vesicular transport, and non-endosomal functions

CANCER SCIENCE, Issue 7 2008
Nobuyuki Tanaka
Endosomal sorting complex required for transport (ESCRT) proteins form a multicomplex sorting machinery that controls multivesicular body (MVB) formation and the sorting of ubiquitinated membrane proteins to the endosomes. Being sorted to the MVB generally results in the lysosome-dependent degradation of cell-surface receptors, and defects in this machinery induce dysregulated receptor traffic and turnover. Recent lessons from gene targeting and silencing methodologies have implicated the ESCRT in normal development, cell differentiation, and growth, as well as in the budding of certain enveloped viruses. Furthermore, it is becoming apparent that the dysregulation of ESCRT proteins is involved in the development of various human diseases, including many types of cancers and neurodegenerative disorders. Here, we summarize the roles of ESCRT proteins in MVB sorting processes and the regulation of tumor cells, and we discuss some of their other functions that are unrelated to vesicular transport. (Cancer Sci 2008; 99: 1293,1303) [source]


Cell entry by human pathogenic arenaviruses

CELLULAR MICROBIOLOGY, Issue 4 2008
Jillian M. Rojek
Summary The arenaviruses Lassa virus (LASV) in Africa and Machupo (MACV), Guanarito (GTOV) and Junin viruses (JUNV) in South America cause severe haemorrhagic fevers in humans with fatality rates of 15,35%. The present review focuses on the first steps of infection with human pathogenic arenaviruses, the interaction with their cellular receptor molecules and subsequent entry into the host cell. While similarities exist in genomic organization, structure and clinical disease caused by pathogenic Old World and New World arenaviruses these pathogens use different primary receptors. The Old World arenaviruses employ ,-dystroglycan, a cellular receptor for proteins of the extracellular matrix, and the human pathogenic New World arenaviruses use the cellular cargo receptor transferrin receptor 1. While the New World arenavirus JUNV enters cells via clathrin-dependent endocytosis, evidence occurred for clathrin-independent entry of the prototypic Old World arenavirus lymphocytic choriomeningitis virus. Upon internalization, arenaviruses are delivered to the endosome, where pH-dependent membrane fusion is mediated by the envelope glycoprotein (GP). While arenavirus GPs share characteristics with class I fusion GPs of other enveloped viruses, unusual mechanistic features of GP-mediated membrane fusion have recently been discovered for arenaviruses with important implications for viral entry. [source]