Check out our New Publishers' Select for Free Articles

Antiviral Research (v.85, #3)

Editorial Board (pp. ii).

Notes to Authors (pp. co3).

Epithelial raft cultures for investigations of virus growth, pathogenesis and efficacy of antiviral agents by G. Andrei; S. Duraffour; J. Van den Oord; R. Snoeck (pp. 431-449).

The organotypic epithelial raft cultures, originally developed to study keratinocytes differentiation, represent a novel approach to the study of viruses able to infect epithelial cells. Organotypic epithelial raft cultures accurately reproduce the process of epithelial differentiation in vitro and can be prepared from normal keratinocytes, explanted epithelial tissue, or established cell lines. This culture system permits cells to proliferate and fully differentiate at the air–liquid interface on a dermal-equivalent support. Normal primary human keratinocytes (PHKs) stratify and fully differentiate in a manner similar to the normal squamous epithelial tissues, while transformed cell lines exhibit dysplastic morphologies similar to the (pre)neoplastic lesions seen in vivo. This three-dimensional (3D) culture system provides an essential tool for investigations of virus growth, virus–host cell interactions, for the genetic analysis of viral proteins and regulatory sequences, and for the evaluation of antiviral agents. The 3D epithelial cultures have proven a breakthrough in the research on papillomaviruses, since their life cycle is strictly linked to the differentiation of the host epithelium. In the last years, several reports have shown the usefulness of the 3D epithelial cultures for the study of other viruses that target at least during a part of their life cycles epithelial cells. The 3D epithelial cultures allow the analysis of virus–host cell interactions in stratified epithelia that more closely resemble the in vivo situation. In this review we describe the advances on research on 3D epithelial cultures for the study of virus growth and pathogenesis of different families of viruses, including papilloma-, herpes-, pox-, adeno-, and parvoviruses.

Keywords: Organotypic epithelial raft cultures; Three-dimensional cultures; Herpesviruses; Poxviruses; Adenoviruses; Parvoviruses; Papillomaviruses

Strategies for development of dengue virus inhibitors by Christian G. Noble; Yen-Liang Chen; Hongping Dong; Feng Gu; Siew Pheng Lim; Wouter Schul; Qing-Yin Wang; Pei-Yong Shi (pp. 450-462).

Antiviral drug discovery is becoming increasingly important due to the global threat of viral disease pandemics. Many members of the genus Flavivirus are significant human pathogens, among which dengue virus (DENV) alone poses a public health threat to 2.5 billion worldwide, leading to 50–100 million human infections each year. Neither vaccine nor effective therapeutics is currently available for DENV. Development of a DENV vaccine has been challenging, because of the need to simultaneously immunize and induce a long-lasting protection against all four serotypes of DENV; an incompletely immunized individual may be sensitized to life-threatening dengue hemorrhagic fever or dengue shock syndrome. The challenges associated with vaccine development have underscored the importance of development of antiviral therapies for DENV and other flaviviruses. Here we review the strategies to identify inhibitors for DENV therapy. Both viral and host proteins essential for viral replication cycle are potential targets for antiviral development. Inhibitors could be identified by multiple approaches, including enzyme-based screening, viral replication-based screening, structure-based rational design, virtual screening, and fragment-based screening. The strategies discussed in this report should be applicable to antiviral development of other viruses.

Keywords: Abbreviations; DENV; dengue virus; WNV; West Nile virus; YFV; yellow fever virus; HCV; hepatitis C virus; HTS; high-throughput screening; RdRp; RNA-dependent RNA polymerase; HIV; human immunodeficiency virus; HSV; herpes simplex virus; UTR; untranslated region; SAR; structure–activity relationship; ER; endoplasmic reticulum; DHF/DSS; dengue hemorrhagic fever/dengue shock syndrome; SPA; scintillation proximity assay; NOAEL; no observed adverse effect levelHigh-throughput screening; Drug discovery; Antiviral; Enzyme assay; Cell-based assay; Flavivirus; Dengue virus

Inhibition of STAT1 methylation is involved in the resistance of hepatitis B virus to Interferon alpha by Jie Li; Feng Chen; Min Zheng; Haihong Zhu; Dongjiu Zhao; Weixia Liu; Wei Liu; Zhi Chen (pp. 463-469).

As a major therapy for hepatitis B virus (HBV) infection, Interferon alpha (IFN-alpha) triggers intracellular signal transduction including JAK-STAT pathway to produce various antiviral effector mechanisms. However, patients with chronic hepatitis B usually show low response to IFN-alpha treatment and the underlying mechanism remains unclear. In the present study, HepG2 and HepG2.2.15 cells were used to examine the Type I IFN receptors expression, phosphorylation and methylation of STAT1. STAT1–PIAS1 interaction in cells was tested by protein co-immunoprecipitation. The potential improvement of S-adenosylmethionine (SAM) in the antiviral effect of IFN-alpha was also investigated. Our data demonstrated that both chains of the Type I IFN receptors were expressed for a much higher extent in HepG2.2.15 cells than in HepG2 cells. HBV inhibited dramatically the methylation rather than the phosphorylation of STAT1, which was consistent with an increased STAT1–PIAS1 interaction. Combined with IFN-alpha, SAM treatment effectively improved STAT1 methylation and attenuated STAT1–PIAS1 binding, followed by increased PKR and 2′,5′-OAS mRNA expression, thus significantly reducing the HBsAg, HBeAg protein levels and HBV DNA load in the supernatant of HepG2.2.15 cells. Less STAT1 methylation and subsequent increased STAT1–PIAS1 interaction are involved in the mechanism of the IFN-alpha-antagonistic activity of HBV. By improving STAT1 methylation, SAM can enhance the antiviral effect of IFN-alpha.

Keywords: Hepatitis B virus; STAT1; PIAS1; Protein methylation; IFN-alpha antagonistic activity

Evaluation of the role of three candidate human kinases in the conversion of the hepatitis C virus inhibitor 2′- C-methyl-cytidine to its 5′-monophosphate metabolite by Nina L. Golitsina; Francis T. Danehy Jr.; Ross Fellows; Erika Cretton-Scott; David N. Standring (pp. 470-481).

Nucleoside analogs are effective inhibitors of the hepatitis C virus (HCV) in the clinical setting. One such molecule, 2′- C-methyl-cytidine (2′-MeC), entered clinical development as NM283, a valine ester prodrug form of 2′-MeC possessing improved oral bioavailability. To be active against HCV, 2′-MeC must be converted to 2′-MeC triphosphate which inhibits NS5B, the HCV RNA-dependent RNA polymerase. Conversion of 2′-MeC to 2′-MeC monophosphate is the first step in 2′-MeC triphosphate production and is thought to be the rate-limiting step. Here we investigate which of three possible enzymes, deoxycytidine kinase (dCK), uridine–cytidine kinase 1 (UCK1), or uridine–cytidine kinase 2 (UCK2), mediate this first phosphorylation step. Purified recombinant enzymes UCK2 and dCK, but not UCK1, could phosphorylate 2′-MeC in vitro. However, siRNA knockdown experiments in three human cell lines (HeLa, Huh7 and HepG2) defined UCK2 and not dCK as the key kinase for the formation of 2′-MeC monophosphate in cultured human cells. These results underscore the importance of confirming enzymatic kinase data with appropriate cell-based assays. Finally, we present data suggesting that inefficient phosphorylation by UCK2 likely limits the antiviral activity of 2′-MeC against HCV. This paves the way for the use of a nucleotide prodrug approach to overcome this limitation.

Keywords: Antiviral drugs; siRNA; Nucleoside/nucleotide derivatives; Metabolism and activation; Uridine–cytidine kinase; Deoxycytidine kinase

Puromycin-sensitive aminopeptidase: An antiviral prodrug activating enzyme by Ulrika Tehler; Cara H. Nelson; Larryn W. Peterson; Chester J. Provoda; John M. Hilfinger; Kyung-Dall Lee; Charles E. McKenna; Gordon L. Amidon (pp. 482-489).

Cidofovir (HPMPC) is a broad-spectrum antiviral agent, currently used to treat AIDS-related human cytomegalovirus retinitis. Cidofovir has recognized therapeutic potential for orthopox virus infections, although its use is hampered by its inherent low oral bioavailability. Val-Ser-cyclic HPMPC (Val-Ser-cHPMPC) is a promising peptide prodrug which has previously been shown by us to improve the permeability and bioavailability of the parent compound in rodent models (. Molecular Pharmaceutics 5, 598–609). Puromycin-sensitive aminopeptidase was partially purified from Caco-2 cell homogenates and identified as a prodrug activating enzyme for Val-Ser-cHPMPC. The prodrug activation process initially involves an enzymatic step where thel-Valine residue is removed by puromycin-sensitive aminopeptidase, a step that is bestatin-sensitive. Subsequent chemical hydrolysis results in the generation of cHPMPC. A recombinant puromycin-sensitive aminopeptidase was generated and its substrate specificity investigated. The k_cat for Val-pNA was significantly lower than that for Ala-pNA, suggesting that some amino acids are preferred over others. Furthermore, the three-fold higher k_cat for Val-Ser-cHPMPC as compared to Val-pNA suggests that the leaving group may play an important role in determining hydrolytic activity. In addition to its ability to hydrolyze a variety of substrates, these observations strongly suggest that puromycin-sensitive aminopeptidase is an important enzyme for activating Val-Ser-cHPMPC in vivo. Taken together, our data suggest that puromycin-sensitive aminopeptidase makes an attractive target for future prodrug design.

Keywords: Abbreviations; APP-S; puromycin-sensitive aminopeptidase; HPMPC; cidofovir, (methyl (; S; )-2-((; S; )-2-amino-3-methyl-butyrylamino)-3-[(; S; )-5-(4-amino-2-oxo-2; H; -pyrimidin-1-ylmethyl)-2-oxido-1,4,2-dioxaphosphinan-2-yloxy]propanoate); cHPMPC; cyclic cidofovir; Val-Ser-cHPMPC; l; -valine-; l; -serine cyclic cidofovir; Val-pNA; l; -valine para-nitroanilide; Ala-pNA; l; -alanine para-nitroanilide; EDC; N; -(3-dimethylaminopropyl)-; N; ′-ethylcarbodiimide; TFA; trifluoroacetic acid; IPTG; isopropyl β-; d; -thiogalactopyranoside; DMSO; dimethyl sulfoxide; PVDF; polyvinylidene difluoride; PBS; phosphate-buffered salineProdrug; Cidofovir; Puromycin-sensitive; Aminopeptidase; Bioavailability; Antiviral

Inhibition of the Epstein–Barr virus lytic cycle by moronic acid by Fang-Rong Chang; Yi-Chung Hsieh; Yung-Fu Chang; Kuo-Hsiung Lee; Yang-Chang Wu; Li-Kwan Chang (pp. 490-495).

Epstein–Barr virus (EBV) expresses two transcription factors, Rta and Zta, during the immediate-early stage of the lytic cycle to activate the transcription of viral lytic genes. Our immunoblotting and flow cytometry analyses find that moronic acid, found in galls of Rhus chinensis and Brazilian propolis, at 10μM inhibits the expression of Rta, Zta, and an EBV early protein, EA-D, after lytic induction with sodium butyrate. This study also finds that moronic acids inhibits the capacity of Rta to activate a promoter that contains an Rta-response element, indicating that moronic acid interferes with the function of Rta. On the other hand, moronic acid does not appear to influence with the transactivation function of Zta. Therefore, the lack of expression of Zta and EA-D after moronic acid treatment is attributable to the inhibition of the transactivation functions of Rta. Because the expression of Zta, EA-D and many EBV lytic genes depends on Rta, the treatment of P3HR1 cells with moronic acid substantially reduces the numbers of EBV particles produced by the cells after lytic induction. This study suggests that moronic acid is a new structural lead for anti-EBV drug development.

Keywords: Moronic acid; Epstein–Barr virus; Lytic cycle

Antiviral prevention of sepsis induced cytomegalovirus reactivation in immunocompetent mice by Meghan R. Forster; Joanne Trgovcich; Peter Zimmerman; Alexander Chang; Cortland Miller; Paul Klenerman; Charles H. Cook (pp. 496-503).

Immunocompetent patients can reactivate latent cytomegalovirus (CMV) during critical illness and reactivation is associated with significantly worse outcomes. Prior to clinical trials in humans to prove causality, we sought to determine an optimal antiviral treatment strategy.Mice latently infected with murine CMV (MCMV) received a septic reactivation trigger and were randomized to receive one of four ganciclovir regimens or saline. Lungs were evaluated for viral transcriptional reactivation and fibrosis after each regimen. Influences of ganciclovir on early sepsis-induced pulmonary inflammation and T-cell activation were studied after sepsis induction.All ganciclovir regimens reduced measurable MCMV transcriptional reactivation, and 10mg/day for 7 or 21 days was most effective. Lower dose (5mg/kg/day) or delayed therapy was associated with significant breakthrough reactivation. Higher doses of ganciclovir given early were associated with the lowest incidence of pulmonary fibrosis, and delay of therapy for 1 week was associated with significantly worse pulmonary fibrosis. Although bacterial sepsis induced activation of MCMV-specific pulmonary T-cells, this activation was not influenced by ganciclovir.These results suggest that antiviral treatment trials in humans should use 10mg/kg/day ganciclovir administered as early as possible in at-risk patients to minimize reactivation events and associated pulmonary injury.

Keywords: Cytomegalovirus reactivation; Antiviral therapy; Murine CMV; Pulmonary injury

ISG15 over-expression inhibits replication of the Japanese encephalitis virus in human medulloblastoma cells by Nai-Wan Hsiao; Jiun-Wei Chen; Tsuey-Ching Yang; Gregg M. Orloff; Yi-Ying Wu; Chih-Ho Lai; Yu-Ching Lan; Cheng-Wen Lin (pp. 504-511).

IFN-stimulated gene 15 (ISG15), an ubiquitin-like protein, is rapidly induced by IFN-α/β, and ISG15 conjugation is associated with the antiviral immune response. Japanese encephalitis virus (JEV), a mosquito-borne neurotropic flavivirus, causes severe central nervous system diseases. We investigated the potential anti-JEV effect of ISG15 over-expression. ISG15 over-expression in human medulloblastoma cells significantly reduced the JEV-induced cytopathic effect and inhibited JEV replication by reducing the viral titers and genomes ( p<0.05, Student's t-test); it also increased activation of the interferon stimulatory response element (ISRE)-luciferase cis-acting reporter in JEV-infected cells ( p<0.05, Chi-square test). Furthermore, Western blotting revealed that ISG15 over-expression increased phosphorylation of IRF-3 (Ser396), JAK2 (Tyr1007/1008) and STAT1 (Tyr701 and Ser727) in JEV-infected cells ( P<0.05, Chi-square test). Confocal imaging indicated that nucleus translocation of transcription factor STAT1 occurred in ISG15-over-expressing cells but not in vector control cells post-JEV infection. ISG15 over-expression activated the expression of STAT1-dependent genes including IRF-3, IFN-β, IL-8, PKR and OAS before and post-JEV infection ( p=0.063, Student's t-test). The results enabled elucidation of the molecular mechanism of ISG15 over-expression against JEV, which will be useful for developing a novel treatment to combat JEV infection.

Keywords: IFN-stimulated gene 15; Japanese encephalitis virus; IRF-3; JAK2; STAT1

Characterization of potential antiviral resistance mutations in hepatitis B virus reverse transcriptase sequences in treatment-naïve Chinese patients by Bao-Ming Liu; Tong Li; Jie Xu; Xiao-Guang Li; Jian-Ping Dong; Ping Yan; Jing-Xian Yang; Ling Yan; Zhi-Yong Gao; Wen-Peng Li; Xie-Wen Sun; Yu-Hua Wang; Xiu-Juan Jiao; Chun-Sheng Hou; Hui Zhuang (pp. 512-519).

Full-length hepatitis B virus (HBV) reverse transcriptase (RT) sequences were amplified and sequenced among 192 nucleos(t)ide analogue (NA)-naïve Chinese patients with chronic hepatitis B. Deduced amino acids (AAs) at 42 previously reported potential NA resistance (NAr) mutation positions in RT region were analyzed. Patients were found with either B-genotype (28.65%) or C-genotype (71.35%) infections. Rt53, rt91, rt124, rt134, rt221, rt224, rt238 and rt256 were identified as B- and C-genotype-dependent polymorphic AA positions. AA substitutions at 11 classical NAr mutation positions, i.e. rt80, rt169, rt173, rt180, rt181, rt184, rt194, rt202, rt204, rt236 and rt250, were not detected. However, potential NAr mutations were found in 30.73% (59/192) isolates, which involved 18 positions including rt53, rt207, rt229, rt238 and rt256, etc. The concomitant AA changes of HBsAg occurred in 16.67% (32/192) isolates including sG145R mutation. One-third of mutation positions were located in functional RT domains (e.g. rt207 and rt233), A–B interdomains (overlapping HBsAg ‘a’ determinant and showing most concomitant immune-associated mutations) and non-A–B interdomains (e.g. rt191 and rt213), respectively. Genotypes B and C each showed several preferred positions to mutate. These results might provide insights into understanding the evolution and selection basis of NAr HBV strains under antiviral therapy.

Keywords: Abbreviations; HBV; hepatitis B virus; NAs; nucleos(t)ide analogues; LMV; lamivudine; ADV; adefovir-dipivoxil; ETV; entecavir; LdT; telbivudine; RT; reverse transcriptase; AA; amino acid; NAr; nucleos(t)ide analogue resistance; CHB; chronic hepatitis B; TNF; tenofovir disoproxil fumarate; HBsAg; hepatitis B surface antigen; ALT; alanine aminotransferase; AST; aspartate aminotransferase; HBeAg; hepatitis B e antigenHepatitis B virus; Resistance; Mutation; Nucleos(t)ide analogue naïve; Genotype; Polymorphic

Identification of hepatitis C virus genotype 2a replicon variants with reduced susceptibility to ribavirin by Su Su Hmwe; Hideki Aizaki; Tomoko Date; Kyoko Murakami; Koji Ishii; Tatsuo Miyamura; Kazuhiko Koike; Takaji Wakita; Tetsuro Suzuki (pp. 520-524).

Ribavirin (RBV), a nucleoside analogue, is used in the treatment of hepatitis C virus (HCV) infection in combination with interferons. However, potential mechanisms of RBV resistance during HCV replication remain poorly understood. Serial passage of cells harboring HCV genotype 2a replicon in the presence of RBV resulted in the reduced susceptibility of the replicon to RBV. Transfection of fresh cells with RNA from RBV-resistant replicon cells demonstrated that the RBV resistance observed is largely replicon-derived. Four major amino acid substitutions: T1134S in NS3, P1969S in NS4B, V2405A in NS5A, and Y2471H in NS5B region, were identified. Site-directed mutagenesis of these mutations into the replicon indicated that Y2471H plays a role in the reduced susceptibility to RBV and leads to decrease in replication fitness. The results, in addition to analysis of sequence database, suggest that HCV variants with reduced susceptibility to RBV identified are preferential to genotype 2a.

Keywords: Hepatitis C virus; Replication; Ribavirin; Drug resistance

Expression of a foreign epitope on infectious pancreatic necrosis virus VP2 capsid protein subviral particle (SVP) and immunogenicity in rainbow trout by Arun K. Dhar; Robert M. Bowers; Christopher G. Rowe; F.C. Thomas Allnutt (pp. 525-531).

Infectious pancreatic necrosis virus (IPNV) is a major viral pathogen of salmonid fish and causes serious economic losses to salmonid aquaculture. Previously, we demonstrated that the IPNV capsid protein, VP2, expressed in yeast self-assembles into subviral particles (SVPs) and injection of these IPNV rVP2 SVPs into rainbow trout elicits an immune response. Immunized fish had reduced viral loads compared to unimmunized fish when challenged with IPNV. To evaluate the suitability of IPNV rVP2 SVPs for future development of multivalent vaccines, a linear epitope of a human oncogene, c-myc, was cloned into the IPNV rVP2 SVP backbone as a model epitope and expressed in yeast. Western blot analyses with anti- c-myc and anti-IPNV antibodies provided positive identification of both the c-myc and VP2 epitopes on the c-myc VP2 SVPs. Transmission electron microscopy of purified chimeric c-myc VP2 SVPs revealed the formation of ∼20nm particles. Rainbow trout immunized with c-myc VP2 SVPs elicited both anti- c-myc and anti-IPNV immune responses. When immunized fish were challenged with IPNV, the viral load in the c-myc VP2 SVP immunized fish was significantly lower than the sham-vaccinated controls. The results indicate that IPNV rVP2 SVPs can tolerate the insertion of foreign epitopes without affecting either the antigenic potential of the epitopes of the backbone protein or the inserted foreign epitope. This opens the possibility of using the IPNV rVP2 SVP platform to express epitopes of other viruses, which could pave the way for development of multivalent subunit vaccines or novel marker vaccines.

Keywords: Subviral particle; Virus-like particle; IPNV; c-myc; Rainbow trout; Chimeric vaccine

Peptide-derivatized dendrimers inhibit human cytomegalovirus infection by blocking virus binding to cell surface heparan sulfate by Anna Luganini; Andrea Giuliani; Giovanna Pirri; Lorena Pizzuto; Santo Landolfo; Giorgio Gribaudo (pp. 532-540).

Dendrimers are hyperbranched synthetic well-defined molecules with a number of potential applications, especially in relation to the need for new antiviral agents. One subclass of dendrimers are peptide-derivatized dendrimers which consist of a peptidyl branching core and covalently attached surface peptide functional units. Few studies have addressed the potential uses of peptide dendrimers as direct-acting antiviral agents. Here, we report on the ability of two peptide dendrimers, SB105 and SB105_A10, to directly and almost completely inhibit human cytomegalovirus (HCMV) replication in both primary fibroblasts and endothelial cells; the agents were also found to inhibit murine CMV replication, whereas they were not able to inhibit adenovirus or vesicular stomatitis virus. The peptide dendrimers prevented adsorption of the HCMV to cells at 4°C, whereas SB104, a dendrimer with a different amino acid sequence within the functional group and minimal anticytomegaloviral activity, was ineffective in blocking HCMV attachment. In effect, SB105_A10 bound to human cells through an interaction with cell surface heparan sulfate and thereby blocked virion attachment to target cells. These results indicate that the SB105 and SB105_A10 dendrimers could provide a useful starting point for the development of novel molecules to block HCMV infection.

Keywords: Human cytomegalovirus; Antivirals; Peptide-derivatized dendrimers; In vitro infection; Inhibition of viral attachment; Heparan sulfate; GCV-resistant strains

Inhibition of Hepatitis E virus replication using short hairpin RNA (shRNA) by Amit Kumar; Subrat Kumar Panda; Hemlata Durgapal; Subrat Kumar Acharya; Shagufta Rehman; Upendra K. Kar (pp. 541-550).

Hepatitis E virus (HEV) is a non-enveloped, single-stranded, positive sense RNA virus, which is a major cause of water-borne hepatitis. RNA interference (RNAi) is a sequence-specific cellular antiviral defence mechanism, induced by double-stranded RNA, which we used to investigate knockdown of several genes and the 3′ cis-acting element (CAE) of HEV. In the present report, shRNAs were developed against the putative helicase and replicase domains and the 3′CAE region of HEV. Production of siRNA was confirmed by northern hybridization. The possible innate response induction due to shRNA expressions was verified by transcript analysis for interferon-β and 2′,5′-oligoadenylate synthetase genes and was found to be absent. Initially, the selected shRNAs were tested for their efficiency against the respective genes/3′CAE using inhibition of fused viral subgenomic target domain–renilla luciferase reporter constructs. The effective shRNAs were studied for their inhibitory effects on HEV replication in HepG2 cells using HEV replicon and reporter replicon. RNAi mediated silencing was demonstrated by reduction of luciferase activity in subgenomic target–reporter constructs and reporter replicon. The real time PCR was used to demonstrate inhibition of native replicon replication in transfected cells. Designed shRNAs were found to be effective in inhibiting virus replication to a variable extent (45–93%).

Keywords: Hepatitis E virus; shRNA; Helicase; Replicase; 3′ cis-acting element; RNA interference; HepG2 cells

TACE antagonists blocking ACE2 shedding caused by the spike protein of SARS-CoV are candidate antiviral compounds by Shiori Haga; Noriyo Nagata; Tadashi Okamura; Norio Yamamoto; Tetsutaro Sata; Naoki Yamamoto; Takehiko Sasazuki; Yukihito Ishizaka (pp. 551-555).

Because outbreaks of severe acute respiratory syndrome coronavirus (SARS-CoV) might reemerge, identifying antiviral compounds is of key importance. Previously, we showed that the cellular factor TNF-α converting enzyme (TACE), activated by the spike protein of SARS-CoV (SARS-S protein), was positively involved in viral entry, implying that TACE is a possible target for developing antiviral compounds. To demonstrate this possibility, we here tested the effects of TACE inhibitors on viral entry. In vitro and in vivo data revealed that the TACE inhibitor TAPI-2 attenuated entry of both pseudotyped virus expressing the SARS-S protein in a lentiviral vector backbone and infectious SARS-CoV. TAPI-2 blocked both the SARS-S protein-induced shedding of angiotensin-converting enzyme 2 (ACE2), a receptor of SARS-CoV, and TNF-α production in lung tissues. Since the downregulation of ACE2 by SARS-S protein was proposed as an etiological event in the severe clinical manifestations, our data suggest that TACE antagonists block SARS-CoV infection and also attenuate its severe clinical outcome.

Keywords: SARS-CoV; TACE; ACE2; Shedding

RNA immunization can protect mice against foot-and-mouth disease virus by Miguel Rodríguez Pulido; Francisco Sobrino; Belén Borrego; Margarita Sáiz (pp. 556-558).

In previous work we have reported the immunization of swine using in vitro-transcribed foot-and-mouth disease virus (FMDV) RNA. With the aim of testing whether RNA-induced immunization can mediate protection against viral infection, a group of Swiss adult mice was inoculated with FMDV infectious transcripts. In most inoculated animals viral RNA was detected in serum at 48-72h postinoculation. A group of the RNA-inoculated mice (11 out of 19) developed significant titers of neutralizing antibodies against FMDV. Among those animals that were successfully challenged with infectious virus (15 out of 19), three out of the eight animals immunized upon RNA inoculation were protected, as infectious virus could not be isolated from sera but specific anti-FMDV antibodies could be readily detected. These results suggest the potential of the inoculation of genetically engineered FMDV RNA for virulence and protection assays in the murine model and allow to explore the suitability of RNA-based FMDV vaccination in natural host animals.

Keywords: Foot-and-mouth disease virus; RNA vaccines; Genetic immunization; In vivo; Foot-and-mouth disease vaccine

Effective siRNAs inhibit the replication of novel influenza A (H1N1) virus by Wu Zhiqiang; Yang Yaowu; Yang Fan; Yang Jian; Hu Yongfeng; Zhao Lina; Wang Jianwei; Jin Qi (pp. 559-561).

In March and April 2009, an entirely novel influenza A (H1N1) virus (NIAV) emerged in Mexico and the USA. During the subsequent months, the virus rapidly spread all over the world by person-to-person transmission. In this report, RNA interference (RNAi) was used as an antiviral agent to inhibit NIAV replication in A549 cells. Ten small interfering RNAs (siRNAs) targeting extremely conserved regions among multiple NIAV genomes could effectively block the replication of NIAV strain A/Beijing/01/2009 (H1N1) in A549 cells. This study may be useful to confront the sudden emergence of NIAV infection.

Keywords: Novel influenza A (H1N1) virus; RNA interference; siRNAs; Conserved regions

Synthesis and antiviral activity of scopadulane-rearranged diterpenes by Miguel A. González; Lee Agudelo; Liliana Betancur-Galvis (pp. 562-565).

A new bioactive diterpene skeleton resulting from a backbone rearrangement is described. Activity of the rearranged product and several derivatives against Herpes Virus Simplex type 2 is reported.

Keywords: Scopadulcic acid; Scopadulane; Scopadurosane; Antiviral; Herpes simplex virus

Sections

Personal tools

Antiviral Research (v.85, #3)

Sections

Personal tools

Local resources

Antiviral Research (v.85, #3)