Description

The Journal of Virology is the best source of broad-based, high-quality, original research concerning viruses. The journal provides fundamental new information using cross-disciplinary approaches of biochemistry, biophysics, cell biology, genetics, immunology, molecular biology, morphology, physiology, and pathogenesis and immunity.

Publisher details

American Society for Microbiology

Publications in this journal

• Kaposi's Sarcoma Associated Herpesvirus Latency Associated Nuclear Antigen Interacts With Multifunctional Angiogenin To Utilize Its Anti-Apoptotic Functions.

  Authors: Paudel N, Sadagopan S, Chakraborty S, Sarek G, Ojala PM, Chandran B

  Journal of Virology.

• APOBEC3A, APOBEC3B and APOBEC3H haplotype 2 restrict Human T-lymphotropic virus type I (HTLV-1).

  Authors: Ooms M, Krikoni A, Kress AK, Simon V, Münk C

  Journal of Virology.

  The human APOBEC3 family consists of seven deaminases (A3A to A3H), some of which display potent antiretroviral activity against HIV-1 and other retroviruses. Studies that analyzed the effect of A3GThe human APOBEC3 family consists of seven deaminases (A3A to A3H), some of which display potent antiretroviral activity against HIV-1 and other retroviruses. Studies that analyzed the effect of A3G on Human T-lymphotropic virus type 1 (HTLV-1) infectivity resulted in conflicting findings and our knowledge on HTLV-1 restriction by other A3 proteins remains limited. Since HTLV-1 targets CD4+ T-cells, much like HIV, we hypothesized that A3 proteins, other than A3G, restrict HTLV-1. All seven human A3 proteins were tested in HTLV-1 reporter and HIV-1 infectivity assays. We show that A3A, A3B and A3H haplotype 2 acted as potent inhibitors of HTLV-1. Wild-type HIV-1, however, was restricted by A3B and A3H hapII, but not by A3A. Catalytic site mutants of A3A, A3B and A3H hapII showed that A3A and A3B restriction of HTLV-1 required deaminase activity. However, A3H hapII acted in a deaminase-independent manner when restricting HTLV-1, while requiring deaminase activity for HIV-1 restriction. We also analyzed A3 editing of HTLV-1 in five T-cell lines obtained from HTLV-1 infected patients. These cell lines contained extensively edited HTLV-1 sequences with G-to-A mutations in dinucleotide contexts suggestive of A3G and other A3 enzyme activities. Comparison of the A3 induced mutations from reporter cells and the patient derived cell lines indicate that A3G but also other A3 members, possibly A3A and A3B, affect HTLV-1 in vivo. Taken together, our data indicates that HTLV-1 is a likely target for multiple A3 proteins.

• 1. A non-fucosylated variant of the anti-HIV-1 MAb b12 has enhanced FcγRIIIa-mediated antiviral activity in vitro but not improved protection against mucosal SHIV challenge in macaques.

  Authors: Moldt B, Shibata-Koyama M, Rakasz EG, Schultz N, Kanda Y, Dunlop DC, Finstad SL, Jin C, Landucci G, Alpert MD [......] Nimmerjahn F, Evans DT, Alter G, Forthal DN, Schmitz JE, Iida S, Poignard P, Watkins DI, Hessell AJ, Burton DR

  Journal of Virology.

• Computational Reconstruction of Bole1a, a Representative Synthetic Hepatitis C Subtype 1a Viral Genome

  Authors: Munshaw S, Bailey J, Liu L, Burke K, Cox A, Ray SC

  Journal of Virology.

• High-risk human papillomavirus E5 oncoprotein displays channel-forming activity sensitive to small molecule inhibitors

  Authors: Wetherill LF, Holmes KK, Verow M, Müller M, Howell G, Harris M, Fishwick C, Stonehouse N, Foster R, Blair GE, Griffin S, Macdonald A

  Journal of Virology. epub ahead of print.

  High-risk human papillomavirus type 16 (HPV16) is the primary causative agent of cervical cancer and therefore responsible for significant morbidity and mortality worldwide. Cellular transformationHigh-risk human papillomavirus type 16 (HPV16) is the primary causative agent of cervical cancer and therefore responsible for significant morbidity and mortality worldwide. Cellular transformation is directly mediated by the expression of viral oncogenes, the least characterized of which, E5, subverts cellular proliferation and immune recognition processes. Despite a growing catalogue of E5-specific host interactions, little is understood of the molecular basis of its function. Here we describe a novel function for HPV16 E5 as an oligomeric channel forming protein, placing it within the virus-encoded "viroporin" family. Development of a novel recombinant E5 expression system showed that E5 formed oligomeric assemblies, of defined luminal diameter and stoichiometry, in membranous environments and that such channels mediated fluorescent dye release from liposomes. Hexameric E5 channel stoichiometry was suggested by native PAGE studies. In lieu of high-resolution structural information, established de novo molecular modeling and design methods permitted the development of the first specific small molecule E5 inhibitor, capable of both abrogating channel activity in vitro and reducing E5-mediated effects on cell signaling pathways. Identification of channel activity should enhance future understanding of the physiological function of E5 and could represent an important target for antiviral intervention.

• Efficient transmission of pandemic H1N1 influenza viruses with high-level oseltamivir resistance.

  Authors: Seibert CW, Rahmat S, Krammer F, Palese P, Bouvier NM

  Journal of Virology.

• High-risk human papillomavirus E5 oncoprotein displays channel-forming activity sensitive to small molecule inhibitors

  Authors: Laura F. Wetherill, Holmes KK, Verow M, Müller M, Howell G, Harris M, Fishwick C, Stonehouse N, Foster R, Blair GE, Griffin S, Macdonald A

  Journal of Virology.

  High-risk human papillomavirus type 16 (HPV16) is the primary causative agent of cervical cancer and therefore responsible for significant morbidity and mortality worldwide. Cellular transformationHigh-risk human papillomavirus type 16 (HPV16) is the primary causative agent of cervical cancer and therefore responsible for significant morbidity and mortality worldwide. Cellular transformation is directly mediated by the expression of viral oncogenes, the least characterized of which, E5, subverts cellular proliferation and immune recognition processes. Despite a growing catalogue of E5-specific host interactions, little is understood of the molecular basis of its function. Here we describe a novel function for HPV16 E5 as an oligomeric channel forming protein, placing it within the virus-encoded "viroporin" family. Development of a novel recombinant E5 expression system showed that E5 formed oligomeric assemblies, of defined luminal diameter and stoichiometry, in membranous environments and that such channels mediated fluorescent dye release from liposomes. Hexameric E5 channel stoichiometry was suggested by native PAGE studies. In lieu of high-resolution structural information, established de novo molecular modeling and design methods permitted the development of the first specific small molecule E5 inhibitor, capable of both abrogating channel activity in vitro and reducing E5-mediated effects on cell signaling pathways. Identification of channel activity should enhance future understanding of the physiological function of E5 and could represent an important target for antiviral intervention.

• RNA Synthesis by the Brome Mosaic Virus RNA-dependent RNA Polymerase in Human Cells Reveals Requirements for De Novo Initiation and Protein-Protein Interaction

  Authors: Ch. V. Subba-Reddy, Brady Tragesser, Zhili Xu, Barry Stein, C. T. Ranjith-Kumar, Cheng Kao

  Journal of Virology.

  Brome mosaic virus (BMV) is a model positive-strand RNA virus whose replication has been studied in a number of surrogate hosts. In transiently-transfected human cells, the BMV polymerase 2aBrome mosaic virus (BMV) is a model positive-strand RNA virus whose replication has been studied in a number of surrogate hosts. In transiently-transfected human cells, the BMV polymerase 2a activated signaling by the innate immune receptor RIG-I, which recognizes de novo initiated non-self RNAs. Active site mutations in 2a abolished RIG-I activation and co-expression of the BMV 1a protein stimulated 2a activity. Mutations previously shown to abolish 1a and 2a interaction prevented the 1a-dependent enhancement of 2a activity. New insights into 1a-2a interaction include determination that the ATPase active site in the helicase domain of 1a is required to enhance 2a activity. In addition, negatively-charged residues between positions 110 and 120 of the 2a sequence contribute to interaction with the 1a helicase-like domain but not the intrinsic polymerase activity. Fluorescence microscopy revealed that the BMV 1a and 2a co-localized to a perinuclear region in human cells. However, no spherule-like structures were detected by immunoelectron microscopy. Sequencing of the RNAs co-immunoprecipitated with RIG-I revealed that the 2a synthesized RNAs are derived from the message used to translate 2a. That is, 2a exhibits a strong cis-preference for BMV RNA2. Strikingly, the 2a RNA products had sequence identical to those from the 5' sequence of the BMV genomic RNAs. These results show that the BMV 2a protein does not require other BMV proteins to initiate BMV RNA synthesis, but that the 1a helicase domain, and likely helicase activity, can affect RNA synthesis by 2a.

• Sangassou virus, the first hantavirus isolate from Africa, displays distinct genetic and functional properties in the group of Murinae-associated hantaviruses

  Authors: Klempa B, Witkowski PT, Popugaeva E, Auste B, Koivogui L, Fichet-Calvet E, Strecker T, Ter Meulen J, Krüger DH

  Journal of Virology.

• Over-Reliance on the Hexon Gene Leading to Misclassification of Human Adenoviruses. Singh G, Robinson CM, Dehghan S, Schmidt T, Seto D, Jones MS, Dyer DW, Chodosh J.

  Authors: Singh G, Robinson CM, Dehghan S, Schmidt T, Seto D, Jones MS, Dyer DW, Chodosh J

  Journal of Virology.

  The genome of human adenovirus (HAdV) D30 was sequenced in depth. Sequence assembly and analysis revealed two distinct viral sequences, each with an identical hexon gene, the same as previouslyThe genome of human adenovirus (HAdV) D30 was sequenced in depth. Sequence assembly and analysis revealed two distinct viral sequences, each with an identical hexon gene, the same as previously reported for HAdV-D30. However, one of the two viruses was found to be a recombinant of HAdV-D29. Exclusive reliance on serum neutralization can lead to mischaracterization of adenoviruses and miss co-infections. Whole genome sequencing remains the gold standard for proper classification of HAdVs.

• Correlation of recombinant integrase activity and functional preintegration complex formation during acute infection by replication-defective integrase mutant human immunodeficiency virus.

  Authors: Li X, Koh Y, Engelman A

  Journal of Virology.

• INHIBITION OF THE LATENT MEMBRANE PROTEIN-1 IMPAIRS THE GROWTH AND TUMORIGENESIS OF AN EBV-LATENCY II TRANSFORMED T-CELL.

  Authors: Ndour PA, Brocqueville G, Ouk TS, Goormachtigh G, Morales O, Mougel A, Bertout J, Melnyk O, Fafeur V, Feuillard J, Coll J, Adriaenssens E

  Journal of Virology.

  The Epstein-Barr virus (EBV) is a common human herpes virus. Its infection is associated with several human malignancies where it expresses a set of latent proteins among which is the latent membraneThe Epstein-Barr virus (EBV) is a common human herpes virus. Its infection is associated with several human malignancies where it expresses a set of latent proteins among which is the latent membrane protein LMP1. LMP1 is able to transform numerous cell types and is considered the main oncogenic protein of EBV. The mechanism of action is based on mimicry to activated members of the TNF receptor superfamily, through its ability to bind similar adapters and to activate signaling pathways. We previously generated two unique models: a monocytic and lymphocytic (NC5) cell line immortalized by EBV which expresses the type II latency program.Here, we generated LMP1 dominant negatives (DNs), based on fusion between green fluorescent protein (GFP) and TES1 or TES2 (Transformation Effectors Site) of LMP1. Then, we generated cell lines conditionally expressing these DNs. These DNs inhibit NFkB and Akt pathways resulting in impairment of survival processes and increased apoptosis in these cell lines. This pro-apoptotic effect is due to reduced interaction of LMP1 with specific adapters and the recruitment of these adapters to DNs which enable generation of an apoptotic complex involving TRADD, FADD and caspase-8. Similar results were obtained with cell lines displaying a latency III program in which LMP1-DNs decrease cell viability. Finally, we prove that synthetic peptides display similar inhibitory effects in EBV infected cells. DNs derived from LMP1 could be used to develop therapeutic approaches in malignant diseases associated with EBV.

• Assessment of the genetic susceptibility of sheep to scrapie by 1 PMCA and comparison 2 with experimental scrapie transmission studies

  Authors: Cecilia Bucalossi, GianMario Cosseddu, Claudia D’Agostino, Michele Angelo Di Bari, Barbara Chiappini, Michela Conte, Francesca Rosone, Luigi De Grossi, Gaia Scavia, Umberto Agrimi, Romolo Nonno, Gabriele Vaccari

  Journal of Virology.

• Adeno-associated virus activates an innate immune response in normal human cells but not osteosarcoma cells.

  Authors: Laredj LN, Beard P

  Journal of Virology.

  Adeno-associated virus (AAV) is a small, DNA-containing dependovirus, with promising potential as a gene delivery vehicle. Given the variety of applications of AAV-based vectors in the treatment ofAdeno-associated virus (AAV) is a small, DNA-containing dependovirus, with promising potential as a gene delivery vehicle. Given the variety of applications of AAV-based vectors in the treatment of genetic disorders, numerous studies have focused on the immunogenicity of recombinant AAV. In general AAV vectors appear not to induce strong inflammatory responses. We have found that AAV2, when it infects the osteosarcoma cells U2OS, can initiate part of its replicative cycle in the absence of helper virus. This does not occur in untransformed cells. We set out to test whether the cellular innate antiviral defences control this susceptibility and found that, in non-immune normal human fibroblasts, AAV2 induces type I interferon production and release, and accumulation of nuclear promyelocytic leukemia bodies. AAV fails to mobilize this defence pathway in the U2OS cells. This permissiveness is in large part due to impairment of the viral sensing machinery in these cells. Our investigations point to Toll-like receptor 9 (TLR9) as a potential intracellular sensor that detects AAV2 and triggers the antiviral state in AAV-infected untransformed cells. Efficient sensing of the AAV genome and the ensuing activation of an innate antiviral response are thus crucial cellular events dictating the parvovirus infectivity in host cells.

• RING Domain Mutations Uncouple TRIM5α Restriction of HIV-1 From Inhibition of Reverse Transcription and Acceleration of Uncoating

  Authors: Amanda Roa, Fumiaki Hayashi, Yang Yang, Maritza Lienlaf, Jing Zhou, Jiong Shi, Satoru Watanabe, Takanori Kigawa, Shigeyuki Yokoyama, Chris Aiken, Felipe Diaz-Griffero

  Journal of Virology.

  Rhesus TRIM5α(TRIM5αrh) is a cytosolic protein that potently restricts HIV-1 at an early post-entry stage, prior to reverse transcription. The ability of TRIM5αrh to block HIV-1 infection has beenRhesus TRIM5α(TRIM5αrh) is a cytosolic protein that potently restricts HIV-1 at an early post-entry stage, prior to reverse transcription. The ability of TRIM5αrh to block HIV-1 infection has been correlated with a decrease of pelletable HIV-1 capsid during infection. To genetically dissect the ability of TRIM5α to block reverse transcription, we studied a set of TRIM5αrh RING domain mutants that potently restrict HIV-1 but allow the occurrence of reverse transcription. These TRIM5αrh RING variants blocked HIV-1 infection after reverse transcription but prior to integration, as suggested by routing of nuclear viral DNA to circularization in the form of 2-LTR circles. The folding of RING domain variants was similar to the wild type, as evaluated by Nuclear Magnetic Resonance. RING domain changes that allowed the occurrence of reverse transcription were impaired in their ability to decrease the amount of pelletable capsid when compared with wild-type TRIM5α. Similar effects of this particular group of mutations were observed with human TRIM5α inhibition of N-MLV. Interestingly, TRIM5αrh RING domain variants also prevented the degradation of TRIM5αrh that occurs following cell entry of HIV-1. These data correlated the block of reverse transcription with the ability of TRIM5αto accelerate uncoating. Collectively, these results suggest that TRIM5αrh blocks HIV-1 reverse transcription by inducing premature viral uncoating in target cells.

• Alpha Interferon and Not Gamma Interferon Inhibits Salmonid Alphavirus Subtype 3 Replication In Vitro

  Authors: Cheng Xu, Tz-Chun Guo, Stephen Mutoloki, Øyvind Haugland, Inderjit S. Marjara, Øystein Evensen

  Journal of Virology.

• The RING domain and the L79 residue of Z protein are involved in both the rescue of nucleocapsids and the incorporation of glycoproteins into infectious chimeric arenavirus-like particles.

  Authors: Casabona JC, Levingston Macleod JM, Loureiro ME, Gomez GA, Lopez N

  Journal of Virology.

• Adenovirus receptors: implications for tropism

  Authors: Arnberg N

  Journal of Virology. 19(3):168-75.

  Adenoviruses (Ads) are the most frequently used viral vectors in gene therapy and cancer therapy. Obstacles to successful clinical application include accumulation of vector and transduction in liverAdenoviruses (Ads) are the most frequently used viral vectors in gene therapy and cancer therapy. Obstacles to successful clinical application include accumulation of vector and transduction in liver cells, coupled with poor transduction of target cells and tissues such as tumours. Many host molecules, including coagulation factor X, have been identified and suggested to serve as mediators of Ad liver tropism. This review summarises current knowledge concerning these molecules and the mechanisms used by Ads to bind to target cells, and considers the prospects of designing vectors that have been detargeted from the liver and retargeted to cells and tissues of interest in the context of gene therapy and cancer therapy.

• Morphogenesis of a highly replicative EGFPVP22 recombinant Marek's disease virus in cell culture.

  Authors: C Denesvre, C Blondeau, M Lemesle, Y Le Vern, D Vautherot, P Roingeard, J.-F. Vautherot

  Journal of virology. 81(22):12348-59.

  Marek's disease virus (MDV) is an alphaherpesvirus for which infection is strictly cell associated in permissive cell culture systems. In contrast to most other alphaherpesviruses, no comprehensiveMarek's disease virus (MDV) is an alphaherpesvirus for which infection is strictly cell associated in permissive cell culture systems. In contrast to most other alphaherpesviruses, no comprehensive ultrastructural study has been published to date describing the different stages of MDV morphogenesis. To circumvent problems linked to nonsynchronized infection and low infectivity titers, we generated a recombinant MDV expressing an enhanced green fluorescent protein fused to VP22, a major tegument protein that is not implicated in virion morphogenesis. Growth of this recombinant virus in cell culture was decreased threefold compared to that of the parental Bac20 virus, but this mutant was still highly replicative. The recombinant virus allowed us to select infected cells by cell-sorting cytometry at late stages of infection for subsequent transmission electron microscopy analysis. Under these conditions, all of the stages of assembly and virion morphogenesis could be observed except extracellular enveloped virions, even at the cell surface. We observed 10-fold fewer naked cytoplasmic capsids than nuclear capsids, and intracellular enveloped virions were very rare. The partial envelopment of capsids in the cytoplasm supports the hypothesis of the acquisition of the final envelope in this cellular compartment. We demonstrate for the first time that, compared to other alphaherpesviruses, MDV seems deficient in three crucial steps of viral morphogenesis, i.e., release from the nucleus, secondary envelopment, and the exocytosis process. The discrepancy between the efficiency with which this MDV mutant spreads in cell culture and the relatively inefficient process of its envelopment and virion release raises the question of the MDV cell-to-cell spreading mechanism.

• Infection of cardiomyocytes and induction of left ventricle dysfunction by neurovirulent polytropic murine retrovirus.

  Authors: Mohammed Khaleduzzaman, Joseph Francis, Meryll E Corbin, Elizabeth McIlwain, Marc Boudreaux, Min Du, Tim W Morgan, Karin E Peterson

  Journal of virology. 81(22):12307-15.

  Viral infections of the heart are a causative factor of myocarditis as well as of sudden, unexpected deaths of children, yet the mechanisms of pathogenesis remain unclear, in part due to theViral infections of the heart are a causative factor of myocarditis as well as of sudden, unexpected deaths of children, yet the mechanisms of pathogenesis remain unclear, in part due to the relatively few animal models of virus-induced myocarditis. In the current study, we examined the ability of polytropic murine retroviruses to infect the heart and induce cardiac dysfunction. In situ hybridization and immunohistochemistry analysis detected virus-infected cardiomyocytes and macrophages in the heart. A significant decrease in left ventricle function, as measured by fractional shortening, was detected in mice infected with the neurovirulent retrovirus Fr98 but not in mice infected with the nonneurovirulent retrovirus Fr54. Virus infection was not associated with consistent findings of fibrosis or substantial cellular infiltrate. Fr98-induced left ventricle dysfunction was associated with a higher virus load, increased mRNA expression of the macrophage marker F4/80, increased chemokine production, and a small number of apoptotic cells in the heart.

• Virus-encoded aminoacyl-tRNA synthetases: structural and functional characterization of mimivirus TyrRS and MetRS.

  Authors: Chantal Abergel, Joëlle Rudinger-Thirion, Richard Giegé, Jean-Michel Claverie

  Journal of virology. 81(22):12406-17.

  Aminoacyl-tRNA synthetases are pivotal in determining how the genetic code is translated in amino acids and in providing the substrate for protein synthesis. As such, they fulfill a key role in aAminoacyl-tRNA synthetases are pivotal in determining how the genetic code is translated in amino acids and in providing the substrate for protein synthesis. As such, they fulfill a key role in a process universally conserved in all cellular organisms from their most complex to their most reduced parasitic forms. In contrast, even complex viruses were not found to encode much translation machinery, with the exception of isolated components such as tRNAs. In this context, the discovery of four aminoacyl-tRNA synthetases encoded in the genome of mimivirus together with a full set of translation initiation, elongation, and termination factors appeared to blur what was once a clear frontier between the cellular and viral world. Functional studies of two mimivirus tRNA synthetases confirmed the MetRS specificity for methionine and the TyrRS specificity for tyrosine and conformity with the identity rules for tRNA(Tyr) for archea/eukarya. The atomic structure of the mimivirus tyrosyl-tRNA synthetase in complex with tyrosinol exhibits the typical fold and active-site organization of archaeal-type TyrRS. However, the viral enzyme presents a unique dimeric conformation and significant differences in its anticodon binding site. The present work suggests that mimivirus aminoacyl-tRNA synthetases function as regular translation enzymes in infected amoebas. Their phylogenetic classification does not suggest that they have been acquired recently by horizontal gene transfer from a cellular host but rather militates in favor of an intricate evolutionary relationship between large DNA viruses and ancestral eukaryotes.

• Fiber shaft-chimeric adenovirus vectors lacking the KKTK motif efficiently infect liver cells in vivo.

  Authors: Nelson C Di Paolo, Oleksandr Kalyuzhniy, Dmitry M Shayakhmetov

  Journal of virology. 81(22):12249-59.

  The molecular mechanisms governing the infectivity of adenovirus (Ad) toward specific cell and tissue types in vivo remain poorly understood. The direct Ad binding to hepatic heparan sulfateThe molecular mechanisms governing the infectivity of adenovirus (Ad) toward specific cell and tissue types in vivo remain poorly understood. The direct Ad binding to hepatic heparan sulfate proteoglycans via the KKTK motif within the fiber shaft domain was suggested to be the major mechanism of Ad liver cell infection in vivo. Here, we describe the generation and in vitro and in vivo infectivity studies of Ad5-based vectors possessing long Ad31- or Ad41-derived fiber shaft domains, which lack the KKTK motif. We found that all the critical early steps of Ad infection, including attachment to the cellular receptor, internalization, and virus genome transfer into the nucleus, occurred with similar levels of efficiency for fiber shaft-chimeric vectors and unmodified Ad5. Upon intravenous delivery into mice, fiber shaft-chimeric vectors accumulated in liver tissue, transduced liver cells, and induced the production of proinflammatory cytokines (tumor necrosis factor alpha and interleukin-6) and the chemokine monocyte chemoattractant protein 1 at levels indistinguishable from those observed for Ad5. Thus, our data provide evidence that the Ad5 fiber shaft amino acid sequence does not play any substantial role in determining adenovirus infectivity toward hepatic cells in vivo. The data obtained contribute to improving our understanding of the molecular mechanisms determining Ad infectivity and biodistribution in vivo and may aid in designing novel Ad-based vectors for gene therapy applications.

• Influenza virus-induced type I interferon leads to polyclonal B-cell activation but does not break down B-cell tolerance.

  Authors: Anne Woods, Fanny Monneaux, Pauline Soulas-Sprauel, Sylviane Muller, Thierry Martin, Anne-Sophie Korganow, Jean-Louis Pasquali

  Journal of virology. 81(22):12525-34.

  The link between infection and autoimmunity is not yet well understood. This study was designed to evaluate if an acute viral infection known to induce type I interferon production, like influenza,The link between infection and autoimmunity is not yet well understood. This study was designed to evaluate if an acute viral infection known to induce type I interferon production, like influenza, can by itself be responsible for the breakdown of immune tolerance and for autoimmunity. We first tested the effects of influenza virus on B cells in vitro. We then infected different transgenic mice expressing human rheumatoid factors (RF) in the absence or in the constitutive presence of the autoantigen (human immunoglobulin G [IgG]) and young lupus-prone mice [(NZB x NZW)F(1)] with influenza virus and looked for B-cell activation. In vitro, the virus induces B-cell activation through type I interferon production by non-B cells but does not directly stimulate purified B cells. In vivo, both RF and non-RF B cells were activated in an autoantigen-independent manner. This activation was abortive since IgM and IgM-RF production levels were not increased in infected mice compared to uninfected controls, whether or not anti-influenza virus human IgG was detected and even after viral rechallenge. As in RF transgenic mice, acute viral infection of (NZB x NZW)F(1) mice induced only an abortive activation of B cells and no increase in autoantibody production compared to uninfected animals. Taken together, these experiments show that virus-induced acute type I interferon production is not able by itself to break down B-cell tolerance in both normal and autoimmune genetic backgrounds.

• The role of NKG2D signaling in inhibition of cytotoxic T-lymphocyte lysis by the Murine cytomegalovirus immunoevasin m152/gp40.

  Authors: Amelia K Pinto, Amanda M Jamieson, David H Raulet, Ann B Hill

  Journal of virology. 81(22):12564-71.

  Three proteins encoded by murine cytomegalovirus (MCMV) -- gp34, encoded by m04 (m04/gp34), gp48, encoded by m06 (m06/gp48), and gp40, encoded by m152 (m152/gp40) -- act together to powerfully impactThree proteins encoded by murine cytomegalovirus (MCMV) -- gp34, encoded by m04 (m04/gp34), gp48, encoded by m06 (m06/gp48), and gp40, encoded by m152 (m152/gp40) -- act together to powerfully impact the ability of primed cytotoxic CD8 T lymphocytes (CTL) to kill virus-infected cells. Of these three, the impact of m152/gp40 on CTL lysis appears greater than would be expected based on its impact on cell surface major histocompatibility complex (MHC) class I. In addition to MHC class I, m152/gp40 also downregulates the RAE-1 family of NKG2D ligands, which can provide costimulation for CD8 T cells. We hypothesized that m152/gp40 may impact CTL lysis so profoundly because it inhibits both antigen presentation and NKG2D-mediated costimulation. We therefore tested the extent to which m152/gp40's ability to inhibit CTL lysis of MCMV-infected cells could be accounted for by its inhibition of NKG2D signaling. As was predictable from the results reported in the literature, NKG2D ligands were not detected by NKG2D tetramer staining of cells infected with wild-type MCMV, whereas those infected with MCMV lacking m152/gp40 displayed measurable levels of the NKG2D ligand. To determine whether NKG2D signaling contributed to the ability of CTL to lyse these cells, we used a blocking anti-NKG2D antibody. Blocking NKG2D signaling did affect the killing of MCMV-infected cells for some epitopes. However, for all epitopes, the impact of m152/gp40 on CTL lysis was much greater than the impact of inhibition of NKG2D signaling. We conclude that the downregulation of NKG2D ligands by MCMV makes only a small contribution to the impact of m152/gp40 on CTL lysis and only for a small subset of CTL.

• Phylogenetic diversity among low-virulence newcastle disease viruses from waterfowl and shorebirds and comparison of genotype distributions to those of poultry-origin isolates.

  Authors: L Mia Kim, Daniel J King, Phillip E Curry, David L Suarez, David E Swayne, David E Stallknecht, Richard D Slemons, Janice C Pedersen, Dennis A Senne, Kevin Winker, Claudio L Afonso

  Journal of virology. 81(22):12641-53.

  Low-virulence Newcastle disease viruses (loNDV) are frequently recovered from wild bird species, but little is known about their distribution, genetic diversity, or potential to cause disease inLow-virulence Newcastle disease viruses (loNDV) are frequently recovered from wild bird species, but little is known about their distribution, genetic diversity, or potential to cause disease in poultry. NDV isolates recovered from cloacal samples of apparently healthy waterfowl and shorebirds (WS) in the United States during 1986 to 2005 were examined for genomic diversity and their potential for virulence (n = 249). In addition 19 loNDV isolates from U.S. live bird markets (LBMs) were analyzed and found to be genetically distinct from NDV used in live vaccines but related to WS-origin NDV. Phylogenetic analysis of the fusion protein identified nine novel genotypes among the class I NDV, and new genomic subgroups were identified among genotypes I and II of the class II viruses. The WS-origin viruses exhibited broad genetic and antigenic diversity, and some WS genotypes displayed a closer phylogenetic relationship to LBM-origin NDV. All NDV were predicted to be lentogenic based upon sequencing of the fusion cleavage site, intracerebral pathogenicity index, or mean death time in embryo assays. The USDA real-time reverse transcription-PCR assay, which targets the matrix gene, identified nearly all of the class II NDV tested but failed to detect class I viruses from both LBM and WS. The close phylogenetic proximity of some WS and LBM loNDV suggests that viral transmission may occur among wild birds and poultry; however, these events may occur unnoticed due to the broad genetic diversity of loNDV, the lentogenic presentation in birds, and the limitations of current rapid diagnostic tools.

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