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The Strategic Advisory Group of Experts (SAGE) on immunization (1) met on 12-14 April 2016. This report summarizes the discussions, conclusions and recommendations. (2) Report from the WHO Department of [...]

Liquid-liquid phase separation is ubiquitous in suspensions of nanoparticles, proteins and colloids. It has an important role in gel formation, protein crystallization and perhaps even as an organizing principle in cellular biology (1,2). With a few notable exceptions (3,4), liquid-liquid phase separation in bulk proceeds through the continuous coalescence of droplets until the system undergoes complete phase separation. But when colloids, nanoparticles or proteins are confined to interfaces, surfaces or membranes, their interactions differ fundamentally from those mediated by isotropic solvents (5,6), and this results in significantly more complex phase behaviour (7-13). Here we show that liquid-liquid phase separation in monolayer membranes composed of two dissimilar chiral colloidal rods gives rise to thermodynamically stable rafts that constantly exchange monomeric rods with the background reservoir to maintain a self-limited size. We visualize and manipulate rafts to quantify their assembly kinetics and to show that membrane distortions arising from the rods' chirality lead to long-range repulsive raft-raft interactions. Rafts assemble into cluster crystals at high densities, but they can also form bonds to yield higher-order structures. Taken together, our observations demonstrate a robust membrane-based pathway for the assembly of monodisperse membrane clusters that is complementary to existing methods for colloid assembly in bulk suspensions (14-16). They also reveal that chiral inclusions in membranes can acquire long-range repulsive interactions, which might more generally have a role in stabilizing assemblages of finite size (13,17)., In the presence of a non-adsorbing polymer, monodisperse rod-like viruses experience effective depletion attractions that drive their lateral association. These interactions can lead to the assembly of colloidal monolayer membranes, [...]

Author(s): Kathryn M. Kauffman [1]; Fatima A. Hussain [1]; Joy Yang [1]; Philip Arevalo [1]; Julia M. Brown [2]; William K. Chang [2]; David VanInsberghe [1]; Joseph Elsherbini [1]; Radhey [...]

The value of incorporating spray-dried plasma (SDP) into the diet of weanling pigs to improve feed intake and growth performance has been well documented. However, limited work has been done to confirm that the spray-drying process eliminates all viral contaminates including porcine circovirus type 2 (PCV2). To determine the effect of spray-drying on PCV2 infectivity, colostrum-fed, crossbred, specific-pathogen-free (SPF) pigs were inoculated with PCV2-contaminated SDP intraperitoneally (SDP-IP) or by oral gavage (SDP-OG), inoculated intraperitoneally with PCV2-positive plasma (POS), or left uninoculated (NEG). The plasma used for the experimentally produced SDP was collected from a SPF pig experimentally infected with a PCV2b isolate. Pigs in the NEG group remained seronegative, and PCV2 viremia was not detected. All pigs in the POS group became PCV2 viremic by 14 d postinoculation (DPI) and seroconverted by 28 DPI. In the SDP-IP group, all pigs became viremic by 35 DPI and seroconverted by 49 DPI. In the SDP-OG group, all animals became viremic by 35 DPI and 2/3 pigs seroconverted by 35 DPI. There were no significant (P > 0.05) differences between anti-PCV2-IgG antibody sample-to-positive ratios among pigs in the POS, SDP-OG, or SDP-IP groups. This work provides direct evidence that the experimental spray-drying process used in this study was not effective in inactivating PCV2b in the plasma of a PCV2-infected pig based on a swine bioassay using PCV2-naive pigs. This work suggests that SDP sourced from pigs could represent a biosecurity risk for the industry. Key words: porcine circovirus type 2, seroconversion, spray-dried plasma, viremia doi: 10.2527/jas.2009-2696

Histone modifications are regarded as the most indispensible phenomena in epigenetics. Of these modifications, lysine methylation is of the greatest complexity and importance as site- and state-specific lysine methylation exerts a plethora of effects on chromatin structure and gene transcription. Notably, paramecium bursaria chlorella viruses encode a conserved SET domain methyltransferase, termed vSET, that functions to suppress host transcription by methylating histone H3 at lysine 27 (H3K27), a mark for eukaryotic gene silencing. Unlike mammalian lysine methyltransferases (KMTs), vSET functions only as a dimer, but the underlying mechanism has remained elusive. In this study, we demonstrate that dimeric vSET operates with negative cooperativity between the two active sites and engages in H3K27 methylation one site at a time. New atomic structures of vSET in the free form and a ternary complex with S-adenosyl homocysteine and a histone H3 peptide and biochemical analyses reveal the molecular origin for the negative cooperativity and explain the substrate specificity of H3K27 methyltransferases. Our study suggests a 'walking' mechanism, by which vSET acts all by itself to globally methylate host H3K27, which is accomplished by the mammalian EZH2 KMT only in the context of the Polycomb repressive complex. chromatin biology | crystallography | histone lysine methylation doi/ 10.1073/pnas.1009911107

Bluetongue disease (BT), discovered north of the Alps in Europe in August 2006 (1-5), causes massive losses of farm ruminants, particularly sheep. Epidemic BT has been caused by serotype 8 [...]

Kyasanur Forest disease virus (KFDV) is a member of the mammalian tick-borne virus group (previously referred to as the tick-borne encephalitis serogroup) of the family Flaviviridae and genus Flavivirus (1). [...]

Foot-and-mouth disease virus (FMDV) is an Aphthovirus within the family Picornaviridae that infects domestic and free-ranging cloven-hoofed mammals. The virus occurs as 7 serotypes, and immunity after vaccination or after [...]

During the past 60 years, the number of emerging pathogens affecting humans has substantially increased (1). Of these emerging infectious diseases, 62% are zoonotic (2), meaning they are naturally hosted [...]

Enterovirus 71 (EV71) is a major causative agent of hand, foot and mouth disease (HFMD), a common febrile disease occurring mainly in young children. Although clinical manifestations of HFMD are usually mild and self limiting, a severe EV71 outbreak can lead to a diverse array of neurological diseases. Identification of the specific cellular receptors is crucial for elucidating the mechanism of early virus-host interactions and the pathogenesis of enteroviruses (1). Here we identify human P-selectin glycoprotein ligand-1 (PSGL-1; CD162), a sialomucin membrane protein expressed on leukocytes that has a major role in early stages of inflammation (2-4), as a functional receptor for EV71 using an expression cloning method by panning (5). The N-terminal region of PSGL-1 binds specifically to EV71. Stable PSGL-1 expression allowed EV71 entry and replication, and development of cytopathic effects in nonsusceptible mouse L929 cells. Five out of eight EV71 strains bound soluble PSGL-1 and used intact PSGL-1 as the primary receptor for infection of Jurkat T cells. Three other EV71 strains did not use PSGL-1, suggesting the presence of strain-specific replication of EV71 in leukocytes. EV71 replicated in nonleukocyte cell lines in a PSGL-1-independent manner, indicating the presence of alternative receptor(s) for EV71. The identification of PSGL-1 as a receptor for EV71 sheds new light on a role for PSGL-1-positive leukocytes in cell tropism and pathogenesis during the course of HFMD and other EV71-mediated diseases., EV71 and coxsackievirus A16 (CVA16) belong to the human enterovirus species A of the genus Enterovirus (6) and are the major causative agents of HFMD. EV71 may cause various neurological [...]

Retinoic acid inducible-gene I (RIG-I) is a cytosolic multidomain protein that detects viral RNA and elicits an antiviral immune response. Two N-terminal caspase activation and recruitment domains (CARDs) transmit the signal, and the regulatory domain prevents signaling in the absence of viral RNA. 5'-triphosphate and double-stranded RNA (dsRNA) are two molecular patterns that enable RIG-I to discriminate pathogenic from self-RNA. However, the function of the DExH box helicase domain that is also required for activity is less clear. Using single-molecule protein-induced fluorescence enhancement, we discovered a robust adenosine 5'-triphosphate-powered dsRNA translocation activity of RIG-I. The CARDs dramatically suppress translocation in the absence of 5'-triphosphate, and the activation by 5'-triphosphate triggers RIG-I to translocate preferentially on dsRNA in cis. This functional integration of two RNA molecular patterns may provide a means to specifically sense and counteract replicating viruses.

Avian influenza viruses are considered to be key contributors to the emergence of human influenza pandemics. A major determinant of infection is the presence of virus receptors on susceptible cells to which the viral haemagglutinin is able to bind. Avian viruses preferentially bind to sialic acid [alpha]2,3-galactose (SA[alpha]2,3-Gal) linked receptors, whereas human strains bind to sialic acid [alpha]2,6-galactose (SA[alpha]2,6-Gal) linked receptors. While ducks are the major reservoir for influenza viruses, they are typically resistant to the effects of viral infection, in contrast to the frequently severe disease observed in chickens. In order to understand whether differences in receptors might contribute to this observation, we studied the distribution of influenza receptors in organs of ducks and chickens using lectin histochemistry with linkage specific lectins and receptor binding assays with swine and avian influenza viruses. Although the intestinal epithelial cells of both species expressed only SA[alpha]2,3-Gal receptors, we found widespread presence of both SA[alpha]2,6-Gal and SA[alpha]2,3-Gal receptors in many organs of both chickens and ducks. Co-expression of both receptors may allow infection of cells with both avian and human viruses and so present a route to genetic reassortment. There was a marked difference in the primary receptor type in the trachea of chickens and ducks. In chicken trachea, SA[alpha]2,6-Gal was the dominant receptor type whereas in ducks SA[alpha]2,3-Gal receptors were most abundant. This suggests that chickens could be more important as an intermediate host for the generation of influenza viruses with increased ability to bind to SA[alpha]2,6-Gal receptors and thus greater potential for infection of humans. Chicken tracheal and intestinal epithelial cells also expressed a broader range of SA[alpha]2,3-Gal receptors (both [beta](1-4)GlcNAc and [beta](1-3)GalNAc subtypes) in contrast to ducks, which suggests that they may be able to support infection with a broader range of avian influenza viruses. KEYWORDS: Host receptors, influenza, interspecies transmission, chicken, duck, INTRODUCTION Influenza A is one of the most important infectious diseases of humans and is responsible for recurrent seasonal disease epidemics. Wild birds are the natural reservoir for all recognized [...]

Cardioviruses cause serious disease, mainly in rodents, including diabetes, myocarditis, encephalomyelitis, and multiple sclerosis-like disseminated encephalomyelitis. Recently, a human virus isolate obtained 25 years ago, termed Saffold virus, was sequenced [...]

The time to suppression of HIV-1 viremia to below the limit of detection of standard clinical assays is an important prognostic indicator for patients on highly active antiretroviral therapy (HAART). Recent clinical trials of the integrase inhibitor raltegravir have demonstrated more rapid viral decay than previously seen with reverse transcriptase (RT) or protease inhibitor-based regimens. Because of the therapeutic importance of drugs that target different steps in the virus life cycle, it is imperative to consider whether viral dynamics are affected by the stage of the viral life cycle at which an antiretroviral drug acts. We use a mathematical model to investigate the effects of various drug classes on the dynamics of HIV-1 decay and show that the stage at which a drug acts affects the dynamics of viral decay. We find that the drug class acting latest in the viral life cycle dictates the dynamics of HIV-1 decay. In general, we find that the later in the life cycle an inhibitor acts, the more rapid the decay in viremia, and we illustrate this by comparing the effect of RT and integrase inhibitors on viral dynamics. We conclude that the rapid decay observed in patients on integrase-inhibitor-containing regimens is not necessarily an indication of greater drug efficacy but rather an expected consequence of the fact that this drug acts later in the life cycle. We propose that clinically observed viral decay rates for HAART regimens should be evaluated in the context of the drug classes that are represented. highly active antiretroviral therapy | integrase inhibitor | viral decay | viral dynamics | raltegravir

The LDL receptor (LDL-R) has been proposed as the viral receptor for Hepatitis C virus (HCV). This hypothesis has been based exclusively on in vitro studies. In human mononuclear cells, LDL-R gene expression has been demonstrated to be parallel and be coordinately regulated to gene expression in the human liver. The purpose of the current study was to determine the mononuclear cell surface expression of the LDL receptor in patients with HCV chronic infection according to viral load. Sixty-eight consecutive untreated chronic hepatitis C patients were studied to determine the mononuclear cell surface expression of the LDL-R. LDL-Rs were quantified at the surface of mononuclear cells in fresh blood samples taken after fasting using flow cytometry. LDL-R expression was significantly associated with LDL-cholesterol (r = -0.25; P = 0.03) and HCV-viral load (r = 0.37, P = 0.002). In multivariate analysis, the LDL-R expression was significantly associated with HCV viral load, whereas genotype, age, body mass index, and fibrosis were not. In conclusion, our data provided by a human study, suggest that the LDL-R may be one of the receptors implicated in HCV replication. fibrosis; lipoproteins; cytometry doi:10.1152/ajpendo.00091.2007

A system is devised to examine T4 phase removal by Tetrahymena thermophila and also the cellular mechanism. The results have indicated the active removal of T4 bacteriophage from fluid by macropinocytosis, followed by digestion in food vacuoles.

Murine norovirus (strain MNV-1) is evaluated for susceptibility to high-pressure processing. It is shown that norovirus can be inactivated by high pressure and has suggested good prospects for inactivation of nonpropagable human norovirus strains in foods.

Many ssRNA/ssDNA viruses bind their genome by highly basic semiflexible peptide arms of capsid proteins. Here, we show that nonspecific electrostatic interactions control both the length of the genome and genome conformations. Analysis of available experimental data shows that the genome length is linear in the net charge on the capsid peptide arms, irrespective of the actual amino acid sequence, with a proportionality coefficient of 1.61 [+ or -] 0.03. This ratio is conserved across all ssRNA/ssDNA viruses with highly basic peptide arms, and is different from the one-to-one charge balance expected of specific binding. Genomic nucleotides are predicted to occupy a radially symmetric spherical shell detached from the viral capsid, in agreement with experimental data. polymer assembly | capsid structure

In this work, we provide evidence of a mechanism to reinforce the strength of an icosahedral virus by using its genomic DNA as a structural element. The mechanical properties of individual empty capsids and DNA-containing virions of the minute virus of mice are investigated by using atomic force microscopy. The stiffness of the empty capsid is found to be isotropic. Remarkably, the presence of the DNA inside the virion leads to an anisotropic reinforcement of the virus stiffness by [approximately equal to] 3%, 40%, and 140% along the fivefold, threefold, and twofold symmetry axes, respectively. A finite element model of the virus indicates that this anisotropic mechanical reinforcement is due to DNA stretches bound to 60 concavities of the capsid. These results, together with evidence of biologically relevant conformational rearrangements of the capsid around pores located at the fivefold symmetry axes, suggest that the bound DNA may reinforce the overall stiffness of the viral particle without canceling the conformational changes needed for its infectivity. capsid | virion | nanomechanics | finite element methods | atomic force microscopy

To date, research on the inactivation of microorganisms by nonequilibrium atmospheric pressure plasmas has mainly been concerned by the killing efficiency and/or with the study of the roles played by various plasma agents (ultraviolet, radicals, ions, etc.) in the inactivation process. In this paper, the authors look at the problem from the cells' side. More specifically, the following questions are asked: What part of the spore structure plays a crucial role in its defense against the unfavorable plasma environment, and if the cells do survive plasma treatment, do they emerge the same or do they undergo some kind of noticeable changes? Although complete and comprehensive answers to these questions are not at the authors' grasp at this time, this paper presents convincing preliminary data that show that the integrity of the proteins of a spore's coat plays a major role in its survivability and that cells that survive air plasma exposure emerge with a changed metabolism. Index Terms--Bacteria, cold plasma, inactivation, metabolism, spores, sterilization.

We examined 10,025 respiratory samples collected for 4 years (2001-2004) and found a 7.1% average annual incidence of human metapneumovirus. The epidemic peak of infection was late winter to spring, [...]

Prior exposure of respiratory epithelial cells to an aqueous-trapped solution of diesel exhaust (D[E.sub.as]) enhances the susceptibility to influenza infections. Here, we examined the effect of D[E.sub.as] on the Toll-like receptor 3 (TLR3) pathway, which is responsible for the recognition of and response to viruses and double-stranded RNA. Flow cytometric and confocal microscopy analyses showed that TLR3 is predominantly expressed in the cytoplasm of respiratory epithelial cells. To examine the effect of DE on TLR3 expression and function, differentiated human bronchial or nasal epithelial cells as well as A549 cells were exposed to D[E.sub.as] and then infected with influenza A or treated with polyriboinosinic acid-polyribocytidylic acid [poly(I:C)], a synthetic form of double-stranded RNA. Exposure to D[E.sub.as] before infection with influenza or stimulation with poly(I:C) significantly upregulated the expression of TLR3. Additionally, preexposure to D[E.sub.as] significantly increased the poly(I:C)-induced expression of IL-6. Overexpression of a dominant-negative mutant form of TNF receptor-associated factor 6 reversed the effects of D[E.sub.as] on poly(I:C)-induced IL-6 expression, suggesting that the response was TLR3 dependent. Similarly, preexposure to D[E.sub.as] significantly increased nuclear levels of interferon regulatory factor 3 and the expression of IFN-[beta] in response to poly(I:C). Pretreatment with wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase, was able to abate the effect of D[E.sub.as] on poly(I:C)-induced IFN-[beta] expression. Together, these results indicate that exposure of respiratory epithelial cells to D[E.sub.as] could potentially alter the response to viral infections by increasing the expression and function of TLR3. epithelial cells; Toll-like receptors; in vitro; respiratory virus

A new reverse transcription-polymerase chain reaction assay was developed for identification of 28 Canadian human parechovirus (HPeV) isolates, including 20 HPeV-1, 3 HPeV-2, and 5 HPeV-3, recovered from 1985 to [...]

The innate immune system recognizes viral dsRNA through two distinct pathways; the Toll-like receptor 3 (TLR3) pathway detects dsRNA phagocytosed in endosomes; the helicases retinoic acidinduced protein I (RIG-I) and melanoma differentiation-associated gene-5 (mda-5) detect cytoplasmic dsRNA generated during viral replication. Both RIG-I and mda-5 can bind polyriboinosinic:polyribocytidylic acid (polyhC), the synthetic analog of viral dsRNA, and mediate type I IFN responses to polyhC and multiple RNA viruses in vitro. We generated mda-5-deficient mice and showed that mda-5 is the dominant receptor mediating type IIFN secretion in response to polyhC in vitro and in vivo. Moreover, mda-5-/- mice exhibited a selectively impaired antiviral response to encephalomyocarditis picornavirus, indicating functional specialization of mda-5 in vivo. innate immunity | virus

Type I interferons, also referred to as IFN-[alpha]/[beta], form the first line of defense against viral infections. Major IFN-[alpha]/[beta] producers in the periphery are the plasmacytoid dendritic cells (pDCs). Constitutive expression of the IFN regulatory factor (IRF)-7 enables pDCs to rapidly synthesize large amounts of IFN-[alpha]/[beta] after viral infection. In the central nervous system (CNS), pDCs are considered to be absent from the parenchyma, and little is known about the cells producing IFN-[alpha]/[beta]. The study presented here aimed to identify the cells producing IFN-[alpha]/[beta] in the CNS in vivo after infection by neurotropic viruses such as Theiler's virus and La Crosse virus. No cells with high constitutive expression of IRF-7 were detected in the CNS of uninfected mice, suggesting the absence of cells equivalent to pDCs. Upon viral infection, IFN-[beta] and some subtypes of IFN-[alpha], but not IFN-[epsilon] or IFN-[kappa], were transcriptionally up-regulated. IFN-[alpha]/[beta] was predominantly produced by scattered parenchymal cells and much less by cells of inflammatory foci. Interestingly, in addition to some macrophages and ependymal cells, neurons turned out to be important producers of both IFN-[alpha] and IFN-[beta]. However, only 3% of the infected neurons produced IFN-[alpha]/[beta], suggesting that some restriction to IFN-[alpha]/[beta] production existed in these cells. All CNS cell types analyzed, including neurons, were able to respond to type I IFN by producing Mx or IRF-7. Our data show that, in vivo, neurons take an active part to the antiviral defense by being both IFN-[alpha]/[beta] producers and responders. central nervous system | viruses | innate immune response | cytokines | interferon regulatory factor 7

Abstract: Peroxisomes are highly dynamic organelles with regard to their metabolic functions, shapes, distribution, movements, and biogenesis. They are also important as sites for the development of some viral pathogens. [...]

Two different West Nile virus (WNV) strains caused lethal encephalitis in a flock of geese and a goshawk in southeastern Hungary in 2003 and 2004, respectively. During the outbreak in [...]

Viruses rely on attachment to specific cell surface receptors to infect host cells. Selective expression of viral receptors has the potential to attenuate infection of susceptible tissues by redirecting virus to cells that cannot support viral replication. We propose that erythrocytes are an ideal instrument for this strategy, because they are present in vast numbers, permeate every organ, and cannot serve as hosts for viral propagation. To test this hypothesis, we generated a transgenic mouse, termed globin transcription factor 1 (GATA1)--coxsackie and adenovirus receptor (CAR), that expressed the CAR on erythrocytes. Coxsackievirus group B (CVB) adhered to the surface of CAR-expressing erythrocytes and was rendered noninfectious. Upon infection with CVB, GATA1-CAR mice had diminished viremia and reduced viral replication in heart, brain, and liver. Furthermore, when faced with a CVB challenge that was lethal to WT littermates, the survival of GATA1-CAR mice was prolonged, and their ultimate mortality was reduced. The GATA1-CAR mouse model presented here demonstrates that erythrocyte expression of CAR limits CVB pathogenesis. Erythrocytes also may be coated with a variety of receptors by nontransgenic methods, making this a very flexible model for the treatment of infectious diseases in humans. coxsackie and adenovirus receptor | virus receptor

An automatic algorithm is presented to segment all the local and global asymmetric units of a three-dimensional density map of icosahedral viruses. The algorithm consists of three major steps operating on the three-dimensional density map, the detection of critical points of the volumetric density function, the detection of global and local symmetry axes, and the boundary segmentation of all the asymmetric units.

Complex signaling pathways regulate the innate immune system of insects, with NF-[kappa]B transcription factors playing a central role in the activation of antimicrobial peptides and other immune genes. Although numerous studies have characterized the immune responses of insects to pathogens, comparatively little is known about the counterstrategies pathogens have evolved to circumvent host defenses. Among the most potent immunosuppressive pathogens of insects are polydnaviruses that are symbiotically associated with parasitoid wasps. Here, we report that the Microplitis demolitor bracovirus encodes a family of genes with homology to inhibitor [kappa]B ([kappa]B) proteins from insects and mammals. Functional analysis of two of these genes, H4 and N5, were conducted in Drosophila $2 cells. Recombinant H4 and N5 greatly reduced the expression of drosomycin and attacin reporter constructs, which are under NF-[kappa]B regulation through the Toll and Imd pathways. Coimmunoprecipitation experiments indicated that H4 and N5 bound to the Rel proteins Dif and Relish, and N5 also weakly bound to Dorsal. H4 and N5 also inhibited binding of Dif and Relish to [kappa]B sites in the promoters of the drosomycin and cecropin A1 genes. Collectively, these results indicate that H4 and N5 function as I[kappa]Bs and, circumstantially, suggest that other I[kappa]B-like gene family members are involved in the suppression of the insect immune system. immunity | virus | virulence | parasite

A recombinant AAV2 (rAAV2) vector encoding antisense RNA to HIV-1 transactivating region (TAR) was evaluated for transduction of human cord blood CD[34.sup.+]CD[38.sup.-] hematopoietic stem cells (HSC) capable of serial engraftment in nonobese diabetic (NOD)/severe combined immunodeficient (SCID) mice. Results revealed long-term multilineage marking in primary and secondary recipients, and significantly, an enrichment of transduced cells in secondary hosts, indicating efficient transduction of multipotential self-renewing HSC. These results were confirmed by the persistence of rAAV marking of clonogenic progenitors in serial analyses of recipient marrow. Upon HIV-1 challenge, the macrophage progeny of transduced CD[34.sup.+] cells expressed antisense RNA and exhibited sustained and significant inhibition of virus replication as compared with controls in every donor tested, without selective pressure. This study represents a clear in vivo demonstration of efficient rAAV2 transduction of human HSC. adeno-associated virus | gene transfer | hematopoiesis | HIV