http://www.virologyj.com The latest research articles published by Virology Journal 2010-07-29T00:00:00Z This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ Background: Human adenoviruses have substantial potential for clinical applications in cancer patients. Conditionally replicating adenovirus vectors (CRAds) include oncolytic adenoviruses in which expression of the immediate early viral transactivator protein E1A is controlled by a cancer cell-selective promoter. To enhance efficacy, CRAds are further armed to contain therapeutic genes. Due to size constraints of the capsid geometry, the capacity for packaging transgenes into adenovirus is, however, limited. To overcome this limitation, the employment of E1A-deleted replication-deficient viruses carrying therapeutic genes in combination with replication-competent CRAd vectors expressing E1A in trans has been proposed. Most trans-complementing studies involved transgene expressions from strong ubiquitous promoters, and thereby rely entirely on the cancer cell specificity of the CRAd vector. Results: Here we tested the trans-complementation of a CRAd and a replication-deficient transgene vector containing the same cancer cell-selective promoter. Hereto, we generated two new vectors expressing IL-2 and CD40L from a bicistronic expression cassette under the control of the melanoma / melanocyte-specific tyrosinase enhancer tyrosinase promoter (TETP), which we previously described for the melanoma-specific CRAd vector AddeltaEP-TETP. These vectors gave rise to tightly controlled melanoma-specific transgene expression levels, which were only 5 to 40-fold lower than those from vectors controlled by the nonselective CMV promoter. Reporter analyses using Ad-CMV-eGFP in combination with AddeltaEP-TETP revealed a high level of trans-complementation in melanoma cells (up to about 30-fold), but not in nonmelanoma cells, unlike the AdCMV-eGFP / wtAd5 binary vector system, which was equally efficient in melanoma and nonmelanoma cells. Similar findings were obtained when replacing the transgene vector AdCMV-eGFP with AdCMV-IL-2 or AdCMV-CD40L. However, the combination of the novel AdTETP-CD40L/IL-2 vector with AddeltaEP-TETP or wtAd5 gave reproducible moderate 3-fold enhancements of IL-2 by trans-complementation only. Conclusions: The cancer cell-selective TETP tested here did not give the expected enforceable transgene expression typically achieved in the adenovirus trans-complementing system. Reasons for this could include virus-mediated down regulation of limiting transcription factors, and / or competition for such factors by different promoters. Whether this finding is unique to the particular promoter system tested here, or also occurs with other promoters warrants further investigations. http://www.virologyj.com/content/7/1/175 Alessandra Curioni Fontecedro Verena Lutschg Ossia Eichhoff Reinhard Dummer Urs Greber Silvio Hemmi Virology Journal 2010, 7:175 2010-07-29T00:00:00Z doi:10.1186/1743-422X-7-175 Virology Journal 1743-422X 7 175 2010-07-29T00:00:00Z PDF From April 2007 to March 2008, cloacal swabs were obtained from 246 casualty raptors recovered by various wildlife rehabilitation centers in the United States. The swabs were placed in a virus transport medium and transported to the laboratory on ice packs. At the laboratory, the samples were pooled with each pool consisting of five samples. All pools (n=50) were screened for the presence of avian influenza virus (AIV) using a real time reverse transcription-polymerase chain reaction (rRT-PCR); one of the pools was found positive. All five samples in this pool were tested individually by rRT-PCR; one sample from a bald eagle was found positive. This sample was inoculated in embryonated chicken eggs for virus isolation and a hemagglutinating virus was isolated. Complete genome sequencing of the isolate revealed a mixed infection with H1N1 and H2N1 subtypes. Further analysis revealed that the PB1-F2 gene sequence of H1N1 virus had the N66S virulence-associated substitution. Further studies on ecology and epidemiology of AIV in raptors are needed to help understand their role in the maintenance and evolution of AIV. http://www.virologyj.com/content/7/1/174 Sagar Goyal Naresh Jindal Yogesh Chander Muthanan Ramakrishnan Patrick Redig Srinand Sreevatsan Virology Journal 2010, 7:174 2010-07-28T00:00:00Z doi:10.1186/1743-422X-7-174 Virology Journal 1743-422X 7 174 2010-07-28T00:00:00Z PDF Monkeypox virus (MPV) is a zoonotic Orthopoxvirus and a potential biothreat agent that causes human disease with varying morbidity and mortality. Members of the Orthopoxvirus genus have been shown to suppress antiviral cell defenses, exploit host cell machinery, and delay infection-induced cell death. However, a comprehensive study of all host genes and virus-targeted host networks during infection is lacking. To better understand viral strategies adopted in manipulating routine host biology on global scale, we investigated the effect of MPV infection on Macaca mulatta kidney epithelial cells (MK2) using GeneChip rhesus macaque genome microarrays. Functional analysis of genes differentially expressed at 3 and 7 hours post infection showed distinctive regulation of canonical pathways and networks. While the majority of modulated histone-encoding genes exhibited sharp copy number increases, many of its transcription regulators were substantially suppressed; suggesting involvement of unknown viral factors in host histone expression. In agreement with known viral dependence on actin in motility, egress, and infection of adjacent cells, our results showed extensive regulation of genes usually involved in controlling actin expression dynamics. Similarly, a substantial ratio of genes contributing to cell cycle checkpoints exhibited concerted regulation that favors cell cycle progression in G1, S, G2 phases, but arrest cells in G2 phase and inhibits entry into mitosis. Moreover, the data showed that large number of infection-regulated genes is involved in molecular mechanisms characteristic of cancer canonical pathways. Interestingly, ten ion channels and transporters showed progressive suppression during the course of infection. Although the outcome of this unusual channel expression on cell osmotic homeostasis remains unknown, instability of cell osmotic balance and membrane potential has been implicated in intracellular pathogens egress. Our results highlight the role of histones, actin, cell cycle regulators, and ion channels in MPV infection, and propose these host functions as attractive research focal points in identifying novel drug intervention sites. http://www.virologyj.com/content/7/1/173 Abdulnaser Alkhalil Rasha Hammamieh Justin Hardick Mohamed Ait Ichou Marti Jett Sofi Ibrahim Virology Journal 2010, 7:173 2010-07-28T00:00:00Z doi:10.1186/1743-422X-7-173 Virology Journal 1743-422X 7 173 2010-07-28T00:00:00Z PDF The importance of the adaptive immune response for secondary influenza infections and protection from a lethal challenge after vaccination has been well documented. However, some controversy still exists concerning the specific involvement of B and T cells during a primary infection. Here, we have followed the survival, weight loss, viral load and lung pathology in Rag2-/- knock-out mice after infection with influenza A virus (H1N1). Infected wild type mice initially lost weight early after infection but then cleared the virus and recovered. Rag2-/- mice, however, showed similar weight loss kinetics in the early stages after infection but weight loss continued post infection and culminated in death. In contrast to wild type mice, Rag2-/- mice were not able to clear the virus, despite an increased inflammatory response. Furthermore, they did not recruit virus-specific lymphocytes into the lung in the later stages after infection and exhibited sustained pulmonary lesions. http://www.virologyj.com/content/7/1/172 Haiya Wu Verena Haist Wolfgang Baumgartner Klaus Schughart Virology Journal 2010, 7:172 2010-07-28T00:00:00Z doi:10.1186/1743-422X-7-172 Virology Journal 1743-422X 7 172 2010-07-28T00:00:00Z PDF Porcine Hokovirus (PHoV) was recently discovered in Hong Kong. This new Parvovirus of pigs is closely related to the human Parvoviruses 4 and 5 (PARV4/5) and bovine Hokovirus (BHoV). So far, nothing is known about the presence and prevalence of PHoV in regions of the world other than Hong Kong. A study was initiated to investigate PHoV in German wild boars from five different geographical regions, using a newly established quantitative real-time PCR assay. Analysis of collected liver and serum samples revealed high overall prevalence (32.7 %; 51/156) of PHoV in wild boars. The prevalence differed between the regions and increased with age. Two near full-length genomes and a large fragment for three additional isolates from different regions were sequenced and used for phylogenetic analysis. The German PHoV sequences from wild boars showed a close relationship with sequences of isolates from Hong Kong. http://www.virologyj.com/content/7/1/171 Cornelia Adlhoch Marco Kaiser Heinz Ellerbrok Georg Pauli Virology Journal 2010, 7:171 2010-07-25T00:00:00Z doi:10.1186/1743-422X-7-171 Virology Journal 1743-422X 7 171 2010-07-25T00:00:00Z PDF Phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway can support the replication of influenza A virus through binding of viral NS1 protein to the Src homology 3 (SH3) domain of p85beta regulatory subunit of PI3K. Here we investigated the effect of heterologously overexpressed SH3 on the replication of different influenza A virus subtypes/strains, and on the phosphorylation of Akt in the virus-infected cells. We found that heterologous SH3 reduced replication of influenza A viruses at varying degrees in a subtype/strain-dependent manner and SH3 overexpression reduced the induction of the phosphorylation of Akt in the cells infected with PR8(H1N1) and ST364(H3N2), but not with ST1233(H1N1), Ph2246(H9N2), and Qa199(H9N2). Our results suggest that interference with the NS1-p85beta interaction by heterologous SH3 can be served as a useful antiviral strategy against influenza A virus infection. http://www.virologyj.com/content/7/1/170 Dan-gui Zhang Wei-zhong Li Ge-fei Wang Yun Su Jun Zeng Chi Zhang Xiang-xing Zeng Xiao-xuan Chen Yan-xuan Xu Kang-sheng Li Virology Journal 2010, 7:170 2010-07-23T00:00:00Z doi:10.1186/1743-422X-7-170 Virology Journal 1743-422X 7 170 2010-07-23T00:00:00Z PDF The Bible describes the case of a woman with high fever cured by our Lord Jesus Christ. Based on the information provided by the gospels of Mark, Matthew and Luke, the diagnosis and the possible etiology of the febrile illness is discussed. Infectious diseases continue to be a threat to humanity, and influenza has been with us since the dawn of human history. If the postulation is indeed correct, the woman with fever in the Bible is among one of the very early description of human influenza disease. http://www.virologyj.com/content/7/1/169 Kam Hon Pak Ng Ting Leung Virology Journal 2010, 7:169 2010-07-21T00:00:00Z doi:10.1186/1743-422X-7-169 Virology Journal 1743-422X 7 169 2010-07-21T00:00:00Z PDF Background: Duck viral enteritis, which is caused by duck enteritis virus (DEV), causes significant economic losses in domestic and wild waterfowls because of the high mortality and low egg production rates. With the purpose of eliminating this disease and decreasing economic loss in the commercial duck industry, researching on glycoprotein K (gK) of DEV may be a new kind of method for preventing and curing this disease. Because glycoproteins project from the virus envelope as spikes and are directly involved in the host immune system and elicitation of the host immune responses, and also play an important role in mediating infection of target cells, the entry into cell for free virus and the maturation or egress of virus . The gK is one of the major envelope glycoproteins of DEV. However, little information correlated with gK is known, such as antigenic and functional characterization. Results: Bioinformatic predictions revealed that the expression of the full-length gK gene (fgK) in a prokaryotic system is difficult because of the presence of suboptimal exon and transmembrane domains at the C-terminal. In this study, we found that the fgK gene might not be expressed in a prokaryotic system in accordance with the bioinformatic predictions. Further, we successfully used bioinformatics tools to guide the prokaryotic expression of the gK gene by designing a novel truncated gK gene (tgK). These findings indicated that bioinformatics provides theoretical data for target gene expression and saves time for our research. The recombinant tgK protein (tgK) was expressed and purified by immobilized metal affinity chromatography (IMAC). Western blotting and indirect enzyme-linked immunosorbent assay (ELISA) showed that the tgK possessed antigenic characteristics similar to native DEV-gK. Conclusions: In this work, the DEV-tgK was expressed successfully in prokaryotic system for the first time, which will provide usefull information for prokaryotic expression of alphaherpesvirus gK homologs, and the recombinant truncated gK possessed antigenic characteristics similar to native DEV gK. Because of the good reactionogenicity, specificity and sensitivity, the purified tgK could be useful for developing a sensitive serum diagnostic kit to monitor DEV outbreaks. http://www.virologyj.com/content/7/1/168 Shunchuan Zhang Guangpeng Ma Jun Xiang Anchun Cheng Mingshu Wang Dekang Zhu Renyong Jia Qihui Luo Zhengli Chen Xiaoyue Chen Virology Journal 2010, 7:168 2010-07-21T00:00:00Z doi:10.1186/1743-422X-7-168 Virology Journal 1743-422X 7 168 2010-07-21T00:00:00Z PDF Context: Chronic HBV infection is a major cause of hepatocellular carcinoma (HCC) which meanwhile has become the 5th most reason for a fatal outcome of cancer. Worldwide, approximately 350 million people are chronically HBV infected and as such of risk to develop HCC, of those an estimated high rate of children. Treatment of chronic infection is sufficient to reduce the rate of HCC but the rate of sustained virological response remains to low, not at least due to emergence of resistant virus strains. Less is known on HBV infection in children despite the extremely high rate of chronicity.Objective, Design, Setting, and Patient: The case of a nine years old male with a 6 year history of chronic HBV infection, of those 5 years with antiviral treatment is described.Interventions and Main Outcome Measure(s): Before our lab was consulted, the patient was unsuccessfully treated with interferon, an obscure drug named Hepon, which should activate antiviral immune response, and Lamivudine, the latter most likely becoming ineffective due to the mergence of resistant subpopulations (rtL180M, rtV207M, two strains with stop codons at position rt188 and rt198, rtM204V (YVDD), rtM204K (YKDD)). Replacement of Lamivudine by adefovir displayed no advantage despite the lack of resistance mutations, thus no decrease in viremia was observed under adefovir treatment.Results and conclusionsNovel mutations in the YMDD motif and its direct neighbourhood were observed, both being compatible with Lamivudine resistance. No mutations were found that are associated with ADF resistance. Both, the clinical course of treatment and the genotypic resistance profile emphasize the need for systematic analyses of the HBV resistance mechanisms and structured therapy concept also for children chronically infected with HBV. http://www.virologyj.com/content/7/1/167 Verena Schildgen Susanne Ziegler Ramona Tillmann Oliver Schildgen Virology Journal 2010, 7:167 2010-07-21T00:00:00Z doi:10.1186/1743-422X-7-167 Virology Journal 1743-422X 7 167 2010-07-21T00:00:00Z PDF Porcine circovirus 2 (PCV2) is a serious problem to the swine industry and can lead to significant negative impacts on profitability of pork production. Syndrome associated with PCV2 is known as porcine circovirus closely associated with post-weaning multisystemic wasting syndrome (PMWS). The capsid (Cap) protein of PCV2 is a major candidate antigen for development of recombinant vaccine and serological diagnostic method. The recombinant Cap protein has the ability to self-assemble into virus-like particles (VLPs) in vitro, it is particularly opportunity to develop the PV2 VLPs vaccine in Escherichia coli,(E.coli), because where the cost of the vaccine must be weighed against the value of the vaccinated pig, when it was to extend use the VLPs vaccine of PCV2. Results: In this report, a highly soluble Cap-tag protein expressed in E.coli was constructed with a p-SMK expression vector with a fusion tag of small ubiquitin-like modiers (SUMO). The recombinant Cap was purified using Ni2+ affinity resins, whereas the tag was used to remove the SUMO protease. Simultaneously, the whole native Cap protein was able to self-assemble into VLPs in vitro when viewed under an electron microscope. The Cap-like particles had a size and shape that resembled the authentic Cap. The result could also be applied in the large-scale production of VLPs of PCV2 and could be used as a diagnostic antigen or a potential VLP vaccine against PCV2 infection in pigs. Conclusion: we have, for the first time, utilized the SUMO fusion motif to successfully express the entire authentic Cap protein of PCV2 in E. coli. After the cleavage of the fusion motif, the nCap protein has the ability to self-assemble into VLPs, which can be used as as a potential vaccine to protect pigs from PCV2-infection. http://www.virologyj.com/content/7/1/166 Shuanghui Yin Shiqi Sun Shunli Yang Youjun Shang Xuepeng Cai Xiangtao Liu Virology Journal 2010, 7:166 2010-07-21T00:00:00Z doi:10.1186/1743-422X-7-166 Virology Journal 1743-422X 7 166 2010-07-21T00:00:00Z PDF