Hans G. Heine

Vaccinia Virus Envelope H3L Protein Binds to Cell Surface Heparan Sulfate and Is Important for Intracellular Mature Virion Morphogenesis and Virus Infection In Vitro and In Vivo

ABSTRACT An immunodominant antigen, p35, is expressed on the envelope of intracellular mature virions (IMV) of vaccinia virus. p35 is encoded by the viral late gene H3L, but its role in the virus life cycle is not known. This report demonstrates that soluble H3L protein binds to heparan sulfate on the cell surface and competes with the binding of vaccinia virus, indicating a role for H3L protein in IMV adsorption to mammalian cells. A mutant virus defective in expression of H3L (H3L−) was constructed; the mutant virus has a small plaque phenotype and 10-fold lower IMV and extracellular enveloped virion titers than the wild-type virus. Virion morphogenesis is severely blocked and intermediate viral structures such as viral factories and crescents accumulate in cells infected with the H3L− mutant virus. IMV from the H3L− mutant virus are somewhat altered and less infectious than wild-type virions. However, cells infected by the mutant virus form multinucleated syncytia after low pH treatment, suggesting that H3L protein is not required for cell fusion. Mice inoculated intranasally with wild-type virus show high mortality and severe weight loss, whereas mice infected with H3L− mutant virus survive and recover faster, indicating that inactivation of the H3L gene attenuates virus virulence in vivo. In summary, these data indicate that H3L protein mediates vaccinia virus adsorption to cell surface heparan sulfate and is important for vaccinia virus infection in vitro and in vivo. In addition, H3L protein plays a role in virion assembly.

A capripoxvirus detection PCR and antibody ELISA based on the major antigen P32, the homolog of the vaccinia virus H3L gene

Sheeppoxvirus (SPV), goatpoxvirus (GPV) and lumpy skin disease virus (LSDV) of cattle belong to the Capripoxvirus genus of the Poxviridae family and can cause significant economic losses in countries where they are endemic. Capripox diagnosis by classical virological methods dependent on live capripox virus is not suitable in countries such as Australia where the virus is exotic and live virus is not available. To develop diagnostic tests based on recombinant material, we cloned and sequenced a 3.7 kb viral DNA fragment of SPV that contained open reading frames homologous to the vaccinia virus J6R, H1L, H2R, H3L and H4L genes. A capripoxvirus specific PCR assay was developed that differentiated between SPV and LSDV on the basis of unique restriction sites in the corresponding PCR fragments. The vaccinia virus H3L homolog was identified as the capripoxvirus P32 antigen. The P32 proteins of SPV and LSDV were expressed in Escherichia coli as a fusion protein with a poly-histidine tag and affinity purified on metal binding resin. The full-length P32 protein contained a transmembrane region close to the carboxy terminus and was membrane associated but could be solubilised in detergent and used as trapping antigen in an antibody detection ELISA. The ELISA was specific for capripoxvirus as only sera from sheep infected with capripoxvirus but not orf or vaccinia virus reacted with the capripoxvirus P32 antigen.

Hendra Virus Vaccine, a One Health Approach to Protecting Horse, Human, and Environmental Health

In recent years, the emergence of several highly pathogenic zoonotic diseases in humans has led to a renewed emphasis on the interconnectedness of human, animal, and environmental health, otherwise known as One Health. For example, Hendra virus (HeV), a zoonotic paramyxovirus, was discovered in 1994, and since then, infections have occurred in 7 humans, each of whom had a strong epidemiologic link to similarly affected horses. As a consequence of these outbreaks, eradication of bat populations was discussed, despite their crucial environmental roles in pollination and reduction of the insect population. We describe the development and evaluation of a vaccine for horses with the potential for breaking the chain of HeV transmission from bats to horses to humans, thereby protecting horse, human, and environmental health. The HeV vaccine for horses is a key example of a One Health approach to the control of human disease.

Experimental infection of horses with Hendra virus/Australia/horse/2008/Redlands.

Early consideration of HeV and institution of infection control are critical for reducing human risk.

A broad spectrum, one-step reverse-transcription PCR amplification of the neuraminidase gene from multiple subtypes of influenza A virus

BackgroundThe emergence of high pathogenicity strains of Influenza A virus in a variety of human and animal hosts, with wide geographic distribution, has highlighted the importance of rapid identification and subtyping of the virus for outbreak management and treatment. Type A virus can be classified into subtypes according to the viral envelope glycoproteins, hemagglutinin and neuraminidase. Here we review the existing specificity and amplification of published primers to subtype neuraminidase genes and describe a new broad spectrum primer pair that can detect all 9 neuraminidase subtypes.ResultsBioinformatic analysis of 3,337 full-length influenza A neuraminidase segments in the NCBI database revealed semi-conserved regions not previously targeted by primers. Two degenerate primers with M13 tags, NA8F-M13 and NA10R-M13 were designed from these regions and used to generate a 253 bp cDNA product. One-step RT-PCR testing was successful in 31/32 (97%) cases using a touchdown protocol with RNA from over 32 different cultured influenza A virus strains representing the 9 neuraminidase subtypes. Frozen blinded clinical nasopharyngeal aspirates were also assayed and were mostly of subtype N2. The region amplified was direct sequenced and then used in database searches to confirm the identity of the template RNA. The RT-PCR fragment generated includes one of the mutation sites related to oseltamivir resistance, H274Y.ConclusionOur one-step RT-PCR assay followed by sequencing is a rapid, accurate, and specific method for detection and subtyping of different neuraminidase subtypes from a range of host species and from different geographical locations.

Promotion of Hendra Virus Replication by MicroRNA 146a

ABSTRACT Hendra virus is a highly pathogenic zoonotic paramyxovirus in the genus Henipavirus. Thirty-nine outbreaks of Hendra virus have been reported since its initial identification in Queensland, Australia, resulting in seven human infections and four fatalities. Little is known about cellular host factors impacting Hendra virus replication. In this work, we demonstrate that Hendra virus makes use of a microRNA (miRNA) designated miR-146a, an NF-κB-responsive miRNA upregulated by several innate immune ligands, to favor its replication. miR-146a is elevated in the blood of ferrets and horses infected with Hendra virus and is upregulated by Hendra virus in human cells in vitro. Blocking miR-146a reduces Hendra virus replication in vitro, suggesting a role for this miRNA in Hendra virus replication. In silico analysis of miR-146a targets identified ring finger protein (RNF)11, a member of the A20 ubiquitin editing complex that negatively regulates NF-κB activity, as a novel component of Hendra virus replication. RNA interference-mediated silencing of RNF11 promotes Hendra virus replication in vitro, suggesting that increased NF-κB activity aids Hendra virus replication. Furthermore, overexpression of the IκB superrepressor inhibits Hendra virus replication. These studies are the first to demonstrate a host miRNA response to Hendra virus infection and suggest an important role for host miRNAs in Hendra virus disease.

Real-time RT-PCR for detection of equine influenza and evaluation using samples from horses infected with A/equine/Sydney/2007 (H3N8).

Equine influenza (EI) virus (H3N8) was identified in the Australian horse population for the first time in August 2007. The principal molecular diagnostic tool used for detection was a TaqMan real-time reverse transcription-polymerase chain reactions (RT-PCR) assay specific for the matrix (MA) gene of influenza virus type A (IVA). As this assay is not specific for EI, we developed a new EI H3-specific TaqMan assay targeting the haemagglutinin (HA) gene of all recent EI H3 strains. The IVA and the EI H3 TaqMan assays were assessed using in vitro transcribed RNA template, virus culture, diagnostic samples from the outbreak and samples from experimentally infected horses. The EI H3 TaqMan assay had a higher diagnostic sensitivity (DSe) when compared to the IVA TaqMan assay and also when using a conventional PCR for EI H3 as a standard of comparison. The performance of both TaqMan assays was compared with an antigen detection ELISA and virus isolation using nasal swabs collected daily from horses experimentally infected with the outbreak strain A/equine/Sydney/2888-8/2007. The EI H3 TaqMan assay was the most sensitive of the assays, able to detect EI from day 1 or 2 post-challenge, as early as virus isolation, and before clinical signs of disease were observed.

Vaccinia virus-expressed bovine ephemeral fever virus G but not GNS glycoprotein induces neutralizing antibodies and protects against experimental infection

Two related glycoproteins (G and G(NS)) encoded in the bovine ephemeral fever virus (BEFV) genome were expressed from recombinant vaccinia viruses (rVV). Both proteins were detected in lysates of rVV-infected cells by labelling with D-[6-3H]glucosamine or by immuno-blotting. The recombinant G protein (mol. mass 79 kDa) appeared slightly smaller than the native G protein but reacted with monoclonal antibodies directed against all defined neutralizing antigenic sites (G1, G2, G3a, G3b and G4). The recombinant G(NS) protein (mol. mass 90kDa) was identical in size to the native G(NS) protein and failed to react by immuno-fluorescence with anti-G protein monoclonal or poly-clonal antibodies. Antisera raised in rabbits against rVV-G or rVV-G(NS) both reacted strongly by immuno-fluorescence and immuno-electron microscopy with BEFV-infected cells. The G protein was localized intracellularly in the endoplasmic reticulum/Golgi complex and at the cell surface associated with budding and mature virus particles. The G(NS) protein also localized intracellularly in the endoplasmic reticulum/Golgi complex; however, at the cell surface it was associated with amorphous structures and not with budding or mature virions. Rabbits vaccinated with rVV-G developed high levels of antibodies which neutralized BEFV grown in either mammalian or insect cells. Cattle vaccinated with rVV-G also produced neutralizing antibodies and were protected against experimental BEFV infection. In contrast, rVV-G(NS) vaccinated rabbits and cattle failed to produce neutralizing antibodies and, after challenge, BEFV was isolated from two-thirds of the vaccinated cattle.

Design and evaluation of consensus PCR assays for henipaviruses

Henipaviruses were first discovered in the 1990s, and their potential threat to public health is of increasing concern with increasing knowledge. Old-world fruit bats are the reservoir hosts for these viruses, and spill-over events cause lethal infections in a wide range of mammalian species, including humans. In anticipation of these spill-over events, and to investigate further the geographical range of these genetically diverse viruses, assays for detection of known and potentially novel strains of henipaviruses are required. The development of multiple consensus PCR assays for the detection of henipaviruses, including both SYBR Green and TaqMan real-time PCRs and a conventional heminested PCR is described. The assays are highly sensitive and have defined specificity. In addition to being useful tools for detection of known and novel henipaviruses, evaluation of assay efficiency and sensitivity across both biological and synthetic templates has provided valuable insight into consensus PCR design and use.

Recombinant fowlpox virus vaccines against Australian virulent Marek's disease virus: gene sequence analysis and comparison of vaccine efficacy in specific pathogen free and production chickens

We have cloned and sequenced the glycoprotein genes gB, gC and gD of the Australian virulent Mareks disease virus (MDV) isolate Woodlands No. 1. The glycoprotein gB and gC sequences were identical to the homologs of other virulent MDV type 1 strains, and the glycoprotein gD sequence contained only one unique amino acid substitution. Recombinant fowlpox viruses (rFPVs) expressing the MDV glycoprotein genes were constructed and their efficacy as vaccines was evaluated in specific pathogen free (SPF) and production chickens. Vaccination with the FPV-gB recombinant protected SPF chickens from Mareks disease mortality and tumour formation following challenge with virulent MDV Woodlands No. 1. The degree of protection from Mareks disease was dependent on the vaccine dose and route of inoculation. The rFPVs expressing gC or gD did not provide protection from Mareks disease. A rFPV expressing both gB and gC did not provide enhanced protection in comparison with the rFPV-gB alone. The rFPV-gB vaccine failed to protect commercial chickens from MD mortality and provided little protection from tumour formation in comparison with the commercial herpesvirus of turkey (HVT) vaccine. The failure to provide protection against MD may be related to the impact of maternally derived immunity to MDV and FPV and possibly the genotype of the chickens.