Publications by authors named "Alain Vanderplasschen"

104 Publications

Alcelaphine herpesvirus 1 genes A7 and A8 regulate viral spread and are essential for malignant catarrhal fever.

PLoS Pathog 2020 03 16;16(3):e1008405. Epub 2020 Mar 16.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine-FARAH, University of Liège, Liège, Belgium.

Alcelaphine herpesvirus 1 (AlHV-1) is a gammaherpesvirus that is carried asymptomatically by wildebeest. Upon cross-species transmission to other ruminants, including domestic cattle, AlHV-1 induces malignant catarrhal fever (MCF), which is a fatal lymphoproliferative disease resulting from proliferation and uncontrolled activation of latently infected CD8+ T cells. Two laboratory strains of AlHV-1 are used commonly in research: C500, which is pathogenic, and WC11, which has been attenuated by long-term maintenance in cell culture. The published genome sequence of a WC11 seed stock from a German laboratory revealed the deletion of two major regions. The sequence of a WC11 seed stock used in our laboratory also bears these deletions and, in addition, the duplication of an internal sequence in the terminal region. The larger of the two deletions has resulted in the absence of gene A7 and a large portion of gene A8. These genes are positional orthologs of the Epstein-Barr virus genes encoding envelope glycoproteins gp42 and gp350, respectively, which are involved in viral propagation and switching of cell tropism. To investigate the degree to which the absence of A7 and A8 participates in WC11 attenuation, recombinant viruses lacking these individual functions were generated in C500. Using bovine nasal turbinate and embryonic lung cell lines, increased cell-free viral propagation and impaired syncytia formation were observed in the absence of A7, whereas cell-free viral spread was inhibited in the absence of A8. Therefore, A7 appears to be involved in cell-to-cell viral spread, and A8 in viral cell-free propagation. Finally, infection of rabbits with either mutant did not induce the signs of MCF or the expansion of infected CD8+ T cells. These results demonstrate that A7 and A8 are both essential for regulating viral spread and suggest that AlHV-1 requires both genes to efficiently spread in vivo and reach CD8+ T lymphocytes and induce MCF.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.ppat.1008405DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098659PMC
March 2020

Current knowledge and future prospects of vaccines against cyprinid herpesvirus 3 (CyHV-3).

Fish Shellfish Immunol 2019 Oct 29;93:531-541. Epub 2019 Jul 29.

Department of Parasitic and Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium. Electronic address:

Aquaculture is one of the world's most important and fastest growing food production sectors, with an average annual growth of 5.8% during the period 2001-2016. Common carp (Cyprinus carpio) is one of the main aquatic species produced for human consumption and is the world's third most produced finfish. Koi carp, on the other hand, are grown as a popular ornamental fish. In the late 1990s, both of these sectors were threatened by the emergence of a deadly disease caused by cyprinid herpesvirus 3 (CyHV-3; initially called koi herpesvirus or KHV). Since then, several research groups have focused their work on developing methods to fight this disease. Despite increasing knowledge about the pathobiology of this virus, there are currently no efficient and cost-effective therapeutic methods available to fight this disease. Facing the lack of efficient treatments, safe and efficacious prophylactic methods such as the use of vaccines represent the most promising approach to the control of this virus. The common carp production sector is not a heavily industrialized production sector and the fish produced have low individual value. Therefore, development of vaccine methods adapted to mass vaccination are more suitable. Multiple vaccine candidates against CyHV-3 have been developed and studied, including DNA, bacterial vector, inactivated, conventional attenuated and recombinant attenuated vaccines. However, there is currently only one vaccine commercially available in limited regions. The present review aims to summarize and evaluate the knowledge acquired from the study of these vaccines against CyHV-3 and provide discussion on future prospects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.fsi.2019.07.079DOI Listing
October 2019

Biocontrol of Carp: The Australian Plan Does Not Stand Up to a Rational Analysis of Safety and Efficacy.

Front Microbiol 2019 30;10:882. Epub 2019 Apr 30.

Department of Parasitic and Infectious Diseases, University of Liège, Liège, Belgium.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmicb.2019.00882DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6503052PMC
April 2019

In vitro and in vivo assessment of eprociclovir as antiviral treatment against testudinid herpesvirus 3 in Hermann's tortoise (Testudo hermanni).

Res Vet Sci 2019 Jun 16;124:20-23. Epub 2019 Feb 16.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Fundamental and Applied Research for Animals & Health (FARAH), Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium.. Electronic address:

Tortoises belonging to the Testudinidae family are infected by Testudinid herpesviruses. Testudinid herpesvirus 3 (TeHV-3) is considered the most pathogenic and affects several tortoise species, particularly those from the Testudo genus. As most species of this genus are endangered contribute to ecological concerns over this virus. Here, we aimed to explore the rational development of an antiviral treatment against TeHV-3 using Hermann's tortoise (Testudo hermanni) as a host model. Ten antiviral compounds were tested in cell culture for their toxicity and their activity against TeHV-3. Eight compounds exhibited different levels of activity against TeHV-3 with either no or only minor cytotoxic effects on cells. Next, eprociclovir (EPV, ciprovir) was selected for further investigations in vivo. Its pharmacokinetic properties were investigated after a single sub-cutaneous administration at 5 or 10 mg/kg. Plasma concentrations remained above half maximal effective concentration (EC) for 2.2 and 4.4 h after administration at 5 and 10 mg/kg, respectively. Finally, EPV toxicity was investigated after administration at the dose of 10 mg/kg, BID for seven consecutive days. As early as one day after initiation of the treatment up to its end, EPV plasma concentration remained under the EC Apathy and anorexia developed after 7 days. Biochemical and anatomopathological examinations revealed nephrotoxic effects of EPV. Altogether, these data suggest that EPV is not a suitable molecule for the treatment of TeHV-3. Further studies are required to determine whether the other molecules identified here for their anti-TeHV-3 activity represent potential candidates for the development of efficacious treatments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.rvsc.2019.02.001DOI Listing
June 2019

Helminth-induced IL-4 expands bystander memory CD8 T cells for early control of viral infection.

Nat Commun 2018 10 30;9(1):4516. Epub 2018 Oct 30.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine - FARAH, University of Liège, Avenue de Cureghem 10, 4000, Liège, Belgium.

Infection with parasitic helminths can imprint the immune system to modulate bystander inflammatory processes. Bystander or virtual memory CD8 T cells (T) are non-conventional T cells displaying memory properties that can be generated through responsiveness to interleukin (IL)-4. However, it is not clear if helminth-induced type 2 immunity functionally affects the T compartment. Here, we show that helminths expand CD44CD62LCXCR3CD49d T cells through direct IL-4 signaling in CD8 T cells. Importantly, helminth-mediated conditioning of T cells provided enhanced control of acute respiratory infection with the murid gammaherpesvirus 4 (MuHV-4). This enhanced control of MuHV-4 infection could further be explained by an increase in antigen-specific CD8 T cell effector responses in the lung and was directly dependent on IL-4 signaling. These results demonstrate that IL-4 during helminth infection can non-specifically condition CD8 T cells, leading to a subsequently raised antigen-specific CD8 T cell activation that enhances control of viral infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-018-06978-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6207712PMC
October 2018

Author Correction: A gammaherpesvirus provides protection against allergic asthma by inducing the replacement of resident alveolar macrophages with regulatory monocytes.

Nat Immunol 2018 Sep;19(9):1035

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine - FARAH, University of Liège, Liège, Belgium.

In the version of this article initially published, the accession code for the RNA-seq data set deposited in the NCBI public repository Sequence Read Archive was missing from the 'Data availability' subsection of the Methods section. The accession code is SRP125477.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41590-017-0024-8DOI Listing
September 2018

Genomic and biologic comparisons of cyprinid herpesvirus 3 strains.

Vet Res 2018 05 2;49(1):40. Epub 2018 May 2.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases (B43b), Fundamental and Applied Research for Animals & Health (FARAH), Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.

Cyprinid herpesvirus 3 (CyHV-3) is the archetypal fish alloherpesvirus and the etiologic agent of a lethal disease in common and koi carp. To date, the genome sequences of only four CyHV-3 isolates have been published, but no comparisons of the biologic properties of these strains have been reported. We have sequenced the genomes of a further seven strains from various geographical sources, and have compared their growth in vitro and virulence in vivo. The major findings were: (i) the existence of the two genetic lineages previously described as European and Asian was confirmed, but inconsistencies between the geographic origin and genotype of some strains were revealed; (ii) potential inter-lineage recombination was detected in one strain, which also suggested the existence of a third, as yet unidentified lineage; (iii) analysis of genetic disruptions led to the identification of non-essential genes and their potential role in virulence; (iv) comparison of the in vitro and in vivo properties of strains belonging to the two lineages revealed that inter-lineage polymorphisms do not contribute to the differences in viral fitness observed; and (v) a negative correlation was observed among strains between viral growth in vitro and virulence in vivo. This study illustrates the importance of coupling genomic and biologic comparisons of viral strains in order to enhance understanding of viral evolution and pathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13567-018-0532-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5930815PMC
May 2018

Biocontrol of invasive carp: Risks abound.

Science 2018 02;359(6378):877

Department of Parasitic and Infectious Diseases, University of Liège, Liège, B-4000, Belgium.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.aar7827DOI Listing
February 2018

Macavirus latency-associated protein evades immune detection through regulation of protein synthesis in cis depending upon its glycin/glutamate-rich domain.

PLoS Pathog 2017 Oct 23;13(10):e1006691. Epub 2017 Oct 23.

Immunology-Vaccinology, Department of infectious and parasitic diseases, Faculty of Veterinary medicine-FARAH, University of Liège, Liège, Belgium.

Alcelaphine herpesvirus 1 (AlHV-1) is a γ-herpesvirus (γ-HV) belonging to the macavirus genus that persistently infects its natural host, the wildebeest, without inducing any clinical sign. However, cross-transmission to other ruminant species causes a deadly lymphoproliferative disease named malignant catarrhal fever (MCF). AlHV-1 ORF73 encodes the latency-associated nuclear antigen (LANA)-homolog protein (aLANA). Recently, aLANA has been shown to be essential for viral persistence in vivo and induction of MCF, suggesting that aLANA shares key properties of other γ-HV genome maintenance proteins. Here we have investigated the evasion of the immune response by aLANA. We found that a glycin/glutamate (GE)-rich repeat domain was sufficient to inhibit in cis the presentation of an epitope linked to aLANA. Although antigen presentation in absence of GE was dependent upon proteasomal degradation of aLANA, a lack of GE did not affect protein turnover. However, protein self-synthesis de novo was downregulated by aLANA GE, a mechanism directly associated with reduced antigen presentation in vitro. Importantly, codon-modification of aLANA GE resulted in increased antigen presentation in vitro and enhanced induction of antigen-specific CD8+ T cell responses in vivo, indicating that mRNA constraints in GE rather than peptidic sequence are responsible for cis-limitation of antigen presentation. Nonetheless, GE-mediated limitation of antigen presentation in cis of aLANA was dispensable during MCF as rabbits developed the disease after virus infection irrespective of the expression of full-length or GE-deficient aLANA. Altogether, we provide evidence that inhibition in cis of protein synthesis through GE is likely involved in long-term immune evasion of AlHV-1 latent persistence in the wildebeest natural host, but dispensable in MCF pathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.ppat.1006691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695634PMC
October 2017

A gammaherpesvirus provides protection against allergic asthma by inducing the replacement of resident alveolar macrophages with regulatory monocytes.

Nat Immunol 2017 Dec 16;18(12):1310-1320. Epub 2017 Oct 16.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine - FARAH, University of Liège, Liège, Belgium.

The hygiene hypothesis postulates that the recent increase in allergic diseases such as asthma and hay fever observed in Western countries is linked to reduced exposure to childhood infections. Here we investigated how infection with a gammaherpesvirus affected the subsequent development of allergic asthma. We found that murid herpesvirus 4 (MuHV-4) inhibited the development of house dust mite (HDM)-induced experimental asthma by modulating lung innate immune cells. Specifically, infection with MuHV-4 caused the replacement of resident alveolar macrophages (AMs) by monocytes with regulatory functions. Monocyte-derived AMs blocked the ability of dendritic cells to trigger a HDM-specific response by the T2 subset of helper T cells. Our results indicate that replacement of embryonic AMs by regulatory monocytes is a major mechanism underlying the long-term training of lung immunity after infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ni.3857DOI Listing
December 2017

Proteomic and Functional Analyses of the Virion Transmembrane Proteome of Cyprinid Herpesvirus 3.

J Virol 2017 11 13;91(21). Epub 2017 Oct 13.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Fundamental and Applied Research for Animals and Health, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium

Virion transmembrane proteins (VTPs) mediate key functions in the herpesvirus infectious cycle. Cyprinid herpesvirus 3 (CyHV-3) is the archetype of fish alloherpesviruses. The present study was devoted to CyHV-3 VTPs. Using mass spectrometry approaches, we identified 16 VTPs of the CyHV-3 FL strain. Mutagenesis experiments demonstrated that eight of these proteins are essential for viral growth (open reading frame 32 [ORF32], ORF59, ORF81, ORF83, ORF99, ORF106, ORF115, and ORF131), and eight are nonessential (ORF25, ORF64, ORF65, ORF108, ORF132, ORF136, ORF148, and ORF149). Among the nonessential proteins, deletion of ORF25, ORF132, ORF136, ORF148, or ORF149 affects viral replication , and deletion of ORF25, ORF64, ORF108, ORF132, or ORF149 impacts plaque size. Lack of ORF148 or ORF25 causes attenuation to a minor or major extent, respectively. The safety and efficacy of a virus lacking ORF25 were compared to those of a previously described vaccine candidate deleted for ORF56 and ORF57 (Δ56-57). Using quantitative PCR, we demonstrated that the ORF25 deleted virus infects fish through skin infection and then spreads to internal organs as reported previously for the wild-type parental virus and the Δ56-57 virus. However, compared to the parental wild-type virus, the replication of the ORF25-deleted virus was reduced in intensity and duration to levels similar to those observed for the Δ56-57 virus. Vaccination of fish with a virus lacking ORF25 was safe but had low efficacy at the doses tested. This characterization of the virion transmembrane proteome of CyHV-3 provides a firm basis for further research on alloherpesvirus VTPs. Virion transmembrane proteins play key roles in the biology of herpesviruses. Cyprinid herpesvirus 3 (CyHV-3) is the archetype of fish alloherpesviruses and the causative agent of major economic losses in common and koi carp worldwide. In this study of the virion transmembrane proteome of CyHV-3, the major findings were: (i) the FL strain encodes 16 virion transmembrane proteins; (ii) eight of these proteins are essential for viral growth ; (iii) seven of the nonessential proteins affect viral growth , and two affect virulence ; and (iv) a mutant lacking ORF25 is highly attenuated but induces moderate immune protection. This study represents a major breakthrough in understanding the biology of CyHV-3 and will contribute to the development of prophylactic methods. It also provides a firm basis for the further research on alloherpesvirus virion transmembrane proteins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.01209-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5640863PMC
November 2017

Identification of an essential virulence gene of cyprinid herpesvirus 3.

Antiviral Res 2017 Sep 6;145:60-69. Epub 2017 Jul 6.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Fundamental and Applied Research for Animals & Health (FARAH), Faculty of Veterinary Medicine, University of Liège, Liège, Belgium. Electronic address:

The genus Cyprinivirus consists of a growing list of phylogenetically related viruses, some of which cause severe economic losses to the aquaculture industry. The archetypal member, cyprinid herpesvirus 3 (CyHV-3) causes mass mortalities worldwide in koi and common carp. A CyHV-3 mutant was described previously that is attenuated in vivo by a deletion affecting two genes (ORF56 and ORF57). The relative contributions of ORF56 and ORF57 to the safety and efficacy profile of this vaccine candidate have now been assessed by analysing viruses individually deleted for ORF56 or ORF57. Inoculation of these viruses into carp demonstrated that the absence of ORF56 did not affect virulence, whereas the absence of ORF57 led to an attenuation comparable to, though slightly less than, that of the doubly deleted virus. To demonstrate further the role of ORF57 as a key virulence factor, a mutant retaining the ORF57 region but unable to express the ORF57 protein was produced by inserting multiple in-frame stop codons into the coding region. Analysis of this virus in vivo revealed a safety and efficacy profile comparable to that of the doubly deleted virus. These findings show that ORF57 encodes an essential CyHV-3 virulence factor. They also indicate that ORF57 orthologues in other cypriniviruses may offer promising targets for the rational design of attenuated recombinant vaccines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.antiviral.2017.07.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5588920PMC
September 2017

The Major Envelope Glycoprotein of Murid Herpesvirus 4 Promotes Sexual Transmission.

J Virol 2017 07 9;91(13). Epub 2017 Jun 9.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine-Fundamental and Applied Research for Animals and Health (FARAH), University of Liège, Liège, Belgium

Gammaherpesviruses are important human and animal pathogens. Infection control has proven difficult because the key process of transmission is ill understood. Murid herpesvirus 4 (MuHV-4), a gammaherpesvirus of mice, is transmitted sexually. We show that this depends on the major virion envelope glycoprotein gp150. gp150 is redundant for host entry, and , it regulates rather than promotes cell binding. We show that gp150-deficient MuHV-4 reaches and replicates normally in the female genital tract after nasal infection but is poorly released from vaginal epithelial cells and fails to pass from the female to the male genital tract during sexual contact. Thus, we show that the regulation of virion binding is a key component of spontaneous gammaherpesvirus transmission. Gammaherpesviruses are responsible for many important diseases in both animals and humans. Some important aspects of their life cycle are still poorly understood. Key among these is viral transmission. Here we show that the major envelope glycoprotein of murid herpesvirus 4 functions not in entry or dissemination but in virion release to allow sexual transmission to new hosts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.00235-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5469271PMC
July 2017

Conserved Fever Pathways across Vertebrates: A Herpesvirus Expressed Decoy TNF-α Receptor Delays Behavioral Fever in Fish.

Cell Host Microbe 2017 Feb;21(2):244-253

Immunology-Vaccinology, FARAH, Faculty of Veterinary Medicine, University of Liège, Liège 4000, Belgium. Electronic address:

Both endotherms and ectotherms (e.g., fish) increase their body temperature to limit pathogen infection. Ectotherms do so by moving to warmer places, hence the term "behavioral fever." We studied the manifestation of behavioral fever in the common carp infected by cyprinid herpesvirus 3, a native carp pathogen. Carp maintained at 24°C died from the infection, whereas those housed in multi-chamber tanks encompassing a 24°C-32°C gradient migrated transiently to the warmest compartment and survived as a consequence. Behavioral fever manifested only at advanced stages of infection. Consistent with this, expression of CyHV-3 ORF12, encoding a soluble decoy receptor for TNF-α, delayed the manifestation of behavioral fever and promoted CyHV-3 replication in the context of a temperature gradient. Injection of anti-TNF-α neutralizing antibodies suppressed behavioral fever, and decreased fish survival in response to infection. This study provides a unique example of how viruses have evolved to alter host behavior to increase fitness.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chom.2017.01.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5301049PMC
February 2017

Genomic duplication and translocation of reactivation transactivator and bZIP-homolog genes is a conserved event in alcelaphine herpesvirus 1.

Sci Rep 2016 12 7;6:38607. Epub 2016 Dec 7.

Fundamental and Applied Research in Animals and Health (FARAH), Immunology-Vaccinology, Faculty of Veterinary Medicine (B43b), University of Liège, Belgium.

Alcelaphine herpesvirus 1 (AlHV-1) is a gammaherpesvirus carried asymptomatically by wildebeest. Upon cross-species transmission, AlHV-1 induces malignant catarrhal fever (MCF), a fatal lymphoproliferative disease of ruminants, including cattle. The strain C500 has been cloned as an infectious, pathogenic bacterial artificial chromosome (BAC) that is used to study MCF. Although AlHV-1 infection can be established in cell culture, multiple passages in vitro cause a loss of virulence associated with rearrangements of the viral genome. Here, sequencing of the BAC clone showed that the long unique region (LUR) of the genome is nearly identical to that of the previously sequenced strain from which the BAC was derived, and identified the duplication and translocation of a region from within LUR, containing the entire coding sequences of ORF50-encoding reactivation transactivator Rta and A6-encoding bZIP protein genes. The duplicated region was further located to a position within the terminal repeat (TR) and its deletion resulted in lower ORF50 expression levels and reduced viral fitness. Finally, the presence of a similar but not identical duplication and translocation containing both genes was found in AlHV-1 strain WC11. These results indicate that selection pressure for enhanced viral fitness may drive the duplication of ORF50 and A6 in AlHV-1.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep38607DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5141506PMC
December 2016

Replacement of Glycoprotein B in Alcelaphine Herpesvirus 1 by Its Ovine Herpesvirus 2 Homolog : Implications in Vaccine Development for Sheep-Associated Malignant Catarrhal Fever.

mSphere 2016 Jul-Aug;1(4). Epub 2016 Aug 3.

Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, USA; Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA.

Vaccine development is a top priority in malignant catarrhal fever (MCF) research. In the case of sheep-associated MCF (SA-MCF) caused by ovine herpesvirus 2 (OvHV-2), progress toward this objective has been hindered by the absence of methods to attenuate or modify the virus, since it cannot be propagated in vitro. As an alternative for vaccine development, in this study, we tested the hypothesis that one of the SA-MCF vaccine candidate targets, OvHV-2 glycoprotein B (gB), could be expressed by a nonpathogenic alcelaphine herpesvirus 1 (AlHV-1) and then evaluated the potential of the AlHV-1/OvHV-2 chimera to be used as a vaccine and a diagnostic tool. The construction and characterization of an AlHV-1/OvHV-2 chimeric virus that is nonpathogenic and expresses an OvHV-2 vaccine target are significant steps toward the development of an SA-MCF vaccine and also provide a valuable means to study OvHV-2 biology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/mSphere.00108-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4973634PMC
August 2016

Behavioral fever in ectothermic vertebrates.

Dev Comp Immunol 2017 01 2;66:84-91. Epub 2016 Jul 2.

Immunology-Vaccinology, Fundamental and Applied Research for Animals & Health (FARAH), Faculty of Veterinary Medicine, University of Liège, Liège, Belgium. Electronic address:

Fever is an evolutionary conserved defense mechanism which is present in both endothermic and ectothermic vertebrates. Ectotherms in response to infection can increase their body temperature by moving to warmer places. This process is known as behavioral fever. In this review, we summarize the current knowledge on the mechanisms of induction of fever in mammals. We further discuss the evolutionary conserved mechanisms existing between fever of mammals and behavioral fever of ectothermic vertebrates. Finally, the experimental evidences supporting an adaptive value of behavioral fever expressed by ectothermic vertebrates are summarized.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.dci.2016.06.027DOI Listing
January 2017

Structural Proteomics of Herpesviruses.

Viruses 2016 Feb 12;8(2). Epub 2016 Feb 12.

Laboratory of Proteomic and Microbiology, Research Institute of Biosciences, University of MONS, 4000 Mons, Belgium.

Herpesviruses are highly prevalent viruses associated with numerous pathologies both in animal and human populations. Until now, most of the strategies used to prevent or to cure these infections have been unsuccessful because these viruses have developed numerous immune evasion mechanisms. Therefore, a better understanding of their complex lifecycle is needed. In particular, while the genome of numerous herpesviruses has been sequenced, the exact composition of virions remains unknown for most of them. Mass spectrometry has recently emerged as a central method and has permitted fundamental discoveries in virology. Here, we review mass spectrometry-based approaches that have recently allowed a better understanding of the composition of the herpesvirus virion. In particular, we describe strategies commonly used for proper sample preparation and fractionation to allow protein localization inside the particle but also to avoid contamination by nonstructural proteins. A collection of other important data regarding post-translational modifications or the relative abundance of structural proteins is also described. This review also discusses the poorly studied importance of host proteins in herpesvirus structural proteins and the necessity to develop a quantitative workflow to better understand the dynamics of the structural proteome. In the future, we hope that this collaborative effort will assist in the development of new strategies to fight these infections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/v8020050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4776205PMC
February 2016

Deletion of Murid Herpesvirus 4 ORF63 Affects the Trafficking of Incoming Capsids toward the Nucleus.

J Virol 2015 Dec 16;90(5):2455-72. Epub 2015 Dec 16.

Immunology-Vaccinology Laboratory, Department of Infectious and Parasitic Diseases (B43b), FARAH, University of Liège, Liège, Belgium

Unlabelled: Gammaherpesviruses are important human and animal pathogens. Despite the fact that they display the classical architecture of herpesviruses, the function of most of their structural proteins is still poorly defined. This is especially true for tegument proteins. Interestingly, a potential role in immune evasion has recently been proposed for the tegument protein encoded by Kaposi's sarcoma-associated herpesvirus open reading frame 63 (ORF63). To gain insight about the roles of ORF63 in the life cycle of a gammaherpesvirus, we generated null mutations in the ORF63 gene of murid herpesvirus 4 (MuHV-4). We showed that disruption of ORF63 was associated with a severe MuHV-4 growth deficit both in vitro and in vivo. The latter deficit was mainly associated with a defect of replication in the lung but did not affect the establishment of latency in the spleen. From a functional point of view, inhibition of caspase-1 or the inflammasome did not restore the growth of the ORF63-deficient mutant, suggesting that the observed deficit was not associated with the immune evasion mechanism identified previously. Moreover, this growth deficit was also not associated with a defect in virion egress from the infected cells. In contrast, it appeared that MuHV-4 ORF63-deficient mutants failed to address most of their capsids to the nucleus during entry into the host cell, suggesting that ORF63 plays a role in capsid movement. In the future, ORF63 could therefore be considered a target to block gammaherpesvirus infection at a very early stage of the infection.

Importance: The important diseases caused by gammaherpesviruses in human and animal populations justify a better understanding of their life cycle. In particular, the role of most of their tegument proteins is still largely unknown. In this study, we used murid herpesvirus 4, a gammaherpesvirus infecting mice, to decipher the role of the protein encoded by the viral ORF63 gene. We showed that the absence of this protein is associated with a severe growth deficit both in vitro and in vivo that was mainly due to impaired migration of viral capsids toward the nucleus during entry. Together, our results provide new insights about the life cycle of gammaherpesviruses and could allow the development of new antiviral strategies aimed at blocking gammaherpesvirus infection at the very early stages.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.02942-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4810702PMC
December 2015

Bovine Herpesvirus 4 Modulates Its β-1,6-N-Acetylglucosaminyltransferase Activity through Alternative Splicing.

J Virol 2016 02 9;90(4):2039-51. Epub 2015 Dec 9.

Immunology-Vaccinology Laboratory, Department of Infectious and Parasitic Diseases, FARAH, University of Liège, Liege, Belgium

Unlabelled: Carbohydrates play major roles in host-virus interactions. It is therefore not surprising that, during coevolution with their hosts, viruses have developed sophisticated mechanisms to hijack for their profit different pathways of glycan synthesis. Thus, the Bo17 gene of Bovine herpesvirus 4 (BoHV-4) encodes a homologue of the cellular core 2 protein β-1,6-N-acetylglucosaminyltransferase-mucin type (C2GnT-M), which is a key player for the synthesis of complex O-glycans. Surprisingly, we show in this study that, as opposed to what is observed for the cellular enzyme, two different mRNAs are encoded by the Bo17 gene of all available BoHV-4 strains. While the first one corresponds to the entire coding sequence of the Bo17 gene, the second results from the splicing of a 138-bp intron encoding critical residues of the enzyme. Antibodies generated against the Bo17 C terminus showed that the two forms of Bo17 are expressed in BoHV-4 infected cells, but enzymatic assays revealed that the spliced form is not active. In order to reveal the function of these two forms, we then generated recombinant strains expressing only the long or the short form of Bo17. Although we did not highlight replication differences between these strains, glycomic analyses and lectin neutralization assays confirmed that the splicing of the Bo17 gene gives the potential to BoHV-4 to fine-tune the global level of core 2 branching activity in the infected cell. Altogether, these results suggest the existence of new mechanisms to regulate the activity of glycosyltransferases from the Golgi apparatus.

Importance: Viruses are masters of adaptation that hijack cellular pathways to allow their growth. Glycans play a central role in many biological processes, and several studies have highlighted mechanisms by which viruses can affect glycosylation. Glycan synthesis is a nontemplate process regulated by the availability of key glycosyltransferases. Interestingly, bovine herpesvirus 4 encodes one such enzyme which is a key enzyme for the synthesis of complex O-glycans. In this study, we show that, in contrast to cellular homologues, this virus has evolved to alternatively express two proteins from this gene. While the first one is enzymatically active, the second results from the alternative splicing of the region encoding the catalytic site of the enzyme. We postulate that this regulatory mechanism could allow the virus to modulate the synthesis of some particular glycans for function at the location and/or the moment of infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.01722-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734007PMC
February 2016

The Structure of the Cyprinid herpesvirus 3 ORF112-Zα·Z-DNA Complex Reveals a Mechanism of Nucleic Acids Recognition Conserved with E3L, a Poxvirus Inhibitor of Interferon Response.

J Biol Chem 2015 Dec 11;290(52):30713-25. Epub 2015 Nov 11.

From the Instituto Gulbenkian de Ciência, 2781-156, Oeiras, Portugal and

In vertebrate species, the innate immune system down-regulates protein translation in response to viral infection through the action of the double-stranded RNA (dsRNA)-activated protein kinase (PKR). In some teleost species another protein kinase, Z-DNA-dependent protein kinase (PKZ), plays a similar role but instead of dsRNA binding domains, PKZ has Zα domains. These domains recognize the left-handed conformer of dsDNA and dsRNA known as Z-DNA/Z-RNA. Cyprinid herpesvirus 3 infects common and koi carp, which have PKZ, and encodes the ORF112 protein that itself bears a Zα domain, a putative competitive inhibitor of PKZ. Here we present the crystal structure of ORF112-Zα in complex with an 18-bp CpG DNA repeat, at 1.5 Å. We demonstrate that the bound DNA is in the left-handed conformation and identify key interactions for the specificity of ORF112. Localization of ORF112 protein in stress granules induced in Cyprinid herpesvirus 3-infected fish cells suggests a functional behavior similar to that of Zα domains of the interferon-regulated, nucleic acid surveillance proteins ADAR1 and DAI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M115.679407DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4692202PMC
December 2015

Cyprinid Herpesvirus 3 Il10 Inhibits Inflammatory Activities of Carp Macrophages and Promotes Proliferation of Igm+ B Cells and Memory T Cells in a Manner Similar to Carp Il10.

J Immunol 2015 Oct 14;195(8):3694-704. Epub 2015 Sep 14.

Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University, 6708WD Wageningen, the Netherlands; and

Cyprinid herpesvirus 3 (CyHV-3) is the causative agent of a lethal disease of carp and encodes for an Il10 homolog (ORF134). Our previous studies with a recombinant ORF134-deleted strain and the derived revertant strain suggested that cyprinid herpesvirus 3 Il10 (CyHV-3 Il10 [cyhv3Il10]) is not essential for viral replication in vitro, or virulence in vivo. In apparent contrast, cyhv3Il10 is one of the most abundant proteins of the CyHV-3 secretome and is structurally very similar to carp Il10 and also human IL10. To date, studies addressing the biological activity of cyhv3Il10 on cells of its natural host have not been performed. To address the apparent contradiction between the presence of a structurally conserved Il10 homolog in the genome of CyHV-3 and the lack of a clear phenotype in vivo using recombinant cyhv3Il10-deleted viruses, we used an in vitro approach to investigate in detail whether cyhv3Il10 exerts any biological activity on carp cells. In this study, we provide direct evidence that cyhv3Il10 is biologically active and, similarly to carp Il10, signals via a conserved Stat3 pathway modulating immune cells of its natural host, carp. In vitro, cyhv3Il10 deactivates phagocytes with a prominent effect on macrophages, while also promoting proliferation of Igm(+) B cells and memory T cells. Collectively, this study demonstrates a clear biological activity of cyhv3Il10 on cells of its natural host and indicates that cyhv3Il10 is a true viral ortholog of carp Il10. Furthermore, to our knowledge, this is the first report on biological activities of a nonmammalian viral Il10 homolog.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4049/jimmunol.1500926DOI Listing
October 2015

The Genome of a Tortoise Herpesvirus (Testudinid Herpesvirus 3) Has a Novel Structure and Contains a Large Region That Is Not Required for Replication In Vitro or Virulence In Vivo.

J Virol 2015 Nov 2;89(22):11438-56. Epub 2015 Sep 2.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Fundamental and Applied Research for Animals & Health (FARAH), Faculty of Veterinary Medicine, University of Liège, Liège, Belgium

Unlabelled: Testudinid herpesvirus 3 (TeHV-3) is the causative agent of a lethal disease affecting several tortoise species. The threat that this virus poses to endangered animals is focusing efforts on characterizing its properties, in order to enable the development of prophylactic methods. We have sequenced the genomes of the two most studied TeHV-3 strains (1976 and 4295). TeHV-3 strain 1976 has a novel genome structure and is most closely related to a turtle herpesvirus, thus supporting its classification into genus Scutavirus, subfamily Alphaherpesvirinae, family Herpesviridae. The sequence of strain 1976 also revealed viral counterparts of cellular interleukin-10 and semaphorin, which have not been described previously in members of subfamily Alphaherpesvirinae. TeHV-3 strain 4295 is a mixture of three forms (m1, m2, and M), in which, in comparison to strain 1976, the genomes exhibit large, partially overlapping deletions of 12.5 to 22.4 kb. Viral subclones representing these forms were isolated by limiting dilution assays, and each replicated in cell culture comparably to strain 1976. With the goal of testing the potential of the three forms as attenuated vaccine candidates, strain 4295 was inoculated intranasally into Hermann's tortoises (Testudo hermanni). All inoculated subjects died, and PCR analyses demonstrated the ability of the m2 and M forms to spread and invade the brain. In contrast, the m1 form was detected in none of the organs tested, suggesting its potential as the basis of an attenuated vaccine candidate. Our findings represent a major step toward characterizing TeHV-3 and developing prophylactic methods against it.

Importance: Testudinid herpesvirus 3 (TeHV-3) causes a lethal disease in tortoises, several species of which are endangered. We have characterized the viral genome and used this information to take steps toward developing an attenuated vaccine. We have sequenced the genomes of two strains (1976 and 4295), compared their growth in vitro, and investigated the pathogenesis of strain 4295, which consists of three deletion mutants. The major findings are that (i) TeHV-3 has a novel genome structure, (ii) its closest relative is a turtle herpesvirus, (iii) it contains interleukin-10 and semaphorin genes (the first time these have been reported in an alphaherpesvirus), (iv) a sizeable region of the genome is not required for viral replication in vitro or virulence in vivo, and (v) one of the components of strain 4295, which has a deletion of 22.4 kb, exhibits properties indicating that it may serve as the starting point for an attenuated vaccine.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.01794-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4645648PMC
November 2015

Small RNA deep sequencing identifies viral microRNAs during malignant catarrhal fever induced by alcelaphine herpesvirus 1.

J Gen Virol 2015 Nov;96(11):3360-3372

Fundamental and Applied Research in Animals and Health (FARAH), Immunology-Vaccinology, Faculty of Veterinary Medicine (B43b), University of Liège, Belgium.

Alcelaphine herpesvirus 1 (AlHV-1) is a c-herpesvirus (c-HV) carried asymptomatically by wildebeest. Upon cross-species transmission, AlHV-1 induces a fatal lymphoproliferative disease named malignant catarrhal fever (MCF) in many ruminants, including cattle, and the rabbit model. Latency has been shown to be essential for MCF induction. However, the mechanisms causing the activation and proliferation of infected CD8+T cells are unknown. Many c-HVs express microRNAs (miRNAs). These small non-coding RNAs can regulate expression of host or viral target genes involved in various pathways and are thought to facilitate viral infection and/or mediate activation and proliferation of infected lymphocytes. The AlHV-1 genome has been predicted to encode a large number of miRNAs. However, their precise contribution in viral infection and pathogenesis in vivo remains unknown. Here, using cloning and sequencing of small RNAs we identified 36 potential miRNAs expressed in a lymphoblastoid cell line propagated from a calf infected with AlHV-1 and developing MCF. Among the sequenced candidate miRNAs, 32 were expressed on the reverse strand of the genome in two main clusters. The expression of these 32 viral miRNAs was further validated using Northern blot and quantitative reverse transcription PCR in lymphoid organs of MCF developing calves or rabbits. To determine the concerted contribution in MCF of 28 viralmiRNAs clustered in the non-protein-coding region of the AlHV-1 genome, a recombinant virus was produced. The absence of these 28 miRNAs did not affect viral growth in vitro or MCF induction in rabbits, indicating that the AlHV-1 miRNAs clustered in this non-protein-coding genomic region are dispensable for MCF induction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1099/jgv.0.000272DOI Listing
November 2015

Cyprinid Herpesvirus 3: An Archetype of Fish Alloherpesviruses.

Adv Virus Res 2015 29;93:161-256. Epub 2015 Apr 29.

Immunology-Vaccinology (B43b), Department of Infectious and Parasitic Diseases, Fundamental and Applied Research for Animals & Health (FARAH), Faculty of Veterinary Medicine, University of Liège, Liège, Belgium. Electronic address:

The order Herpesvirales encompasses viruses that share structural, genetic, and biological properties. However, members of this order infect hosts ranging from molluscs to humans. It is currently divided into three phylogenetically related families. The Alloherpesviridae family contains viruses infecting fish and amphibians. There are 12 alloherpesviruses described to date, 10 of which infect fish. Over the last decade, cyprinid herpesvirus 3 (CyHV-3) infecting common and koi carp has emerged as the archetype of fish alloherpesviruses. Since its first description in the late 1990s, this virus has induced important economic losses in common and koi carp worldwide. It has also had negative environmental implications by affecting wild carp populations. These negative impacts and the importance of the host species have stimulated studies aimed at developing diagnostic and prophylactic tools. Unexpectedly, the data generated by these applied studies have stimulated interest in CyHV-3 as a model for fundamental research. This review intends to provide a complete overview of the knowledge currently available on CyHV-3.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/bs.aivir.2015.03.001DOI Listing
February 2016

The site of administration influences both the type and the magnitude of the immune response induced by DNA vaccine electroporation.

Vaccine 2015 Jun 14;33(28):3179-85. Epub 2015 May 14.

Université catholique de Louvain, Louvain Drug Research Institute, Advanced Drug Delivery and Biomaterials, Brussels, Belgium. Electronic address:

We investigated the influence of the site of administration of DNA vaccine on the induced immune response. DNA vaccines were administered by electroporation at three different sites: tibial cranial muscle, abdominal skin and ear pinna. Aiming to draw general conclusions about DNA vaccine delivery, we successively used several plasmids encoding either luciferase and ovalbumin as models or gp160 and P1A as vaccines against HIV and P815 mastocytoma, respectively. Low levels and duration of luciferase transgene expression were observed after electroporation of the abdominal skin, partly explaining its lower immunogenic performance as compared to the other sites of administration. Analyses of OT-I CD8+ and OT-II CD4+ T cell responses highlighted the differential impact of the delivery site on the elicited immune response. Muscle electroporation induced the strongest humoral immune response and both muscle and ear pinna sites induced cellular immunity against gp160. Ear pinna delivery generated the highest level of CTL responses against P1A but electroporation of muscle and ear pinna were equally efficient in delaying P815 growth and improving mice survival. The present study demonstrated that the site of administration is a key factor to be tested in the development of DNA vaccine.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.vaccine.2015.05.005DOI Listing
June 2015

The α2,3-sialyltransferase encoded by myxoma virus is a virulence factor that contributes to immunosuppression.

PLoS One 2015 23;10(2):e0118806. Epub 2015 Feb 23.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, FARAH, University of Liège, Liège, Belgium.

Myxoma virus (MYXV) induces a lethal disease called Myxomatosis in European rabbits. MYXV is one of the rare viruses that encodes an α2,3-sialyltransferase through its M138L gene. In this study, we showed that although the absence of the enzyme was not associated with any in vitro deficit, the M138L deficient strains are highly attenuated in vivo. Indeed, while all rabbits infected with the parental and the revertant strains died within 9 days post-infection from severe myxomatosis, all but one rabbit inoculated with the M138L deficient strains survived the infection. In primary lesions, this resistance to the infection was associated with an increased ability of innate immune cells, mostly neutrophils, to migrate to the site of virus replication at 4 days post-infection. This was followed by the development of a better specific immune response against MYXV. Indeed, at day 9 post-infection, we observed an important proliferation of lymphocytes and an intense congestion of blood vessels in lymph nodes after M138L knockouts infection. Accordingly, in these rabbits, we observed an intense mononuclear cell infiltration throughout the dermis in primary lesions and higher titers of neutralizing antibodies. Finally, this adaptive immune response provided protection to these surviving rabbits against a challenge with the MYXV WT strain. Altogether, these results show that expression of the M138L gene contributes directly or indirectly to immune evasion by MYXV. In the future, these results could help us to better understand the pathogenesis of myxomatosis but also the importance of glycans in regulation of immune responses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0118806PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338283PMC
January 2016

Rational development of an attenuated recombinant cyprinid herpesvirus 3 vaccine using prokaryotic mutagenesis and in vivo bioluminescent imaging.

PLoS Pathog 2015 Feb 20;11(2):e1004690. Epub 2015 Feb 20.

Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Fundamental and Applied Research for Animals & Health (FARAH), Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.

Cyprinid herpesvirus 3 (CyHV 3) is causing severe economic losses worldwide in common and koi carp industries, and a safe and efficacious attenuated vaccine compatible with mass vaccination is needed. We produced single deleted recombinants using prokaryotic mutagenesis. When producing a recombinant lacking open reading frame 134 (ORF134), we unexpectedly obtained a clone with additional deletion of ORF56 and ORF57. This triple deleted recombinant replicated efficiently in vitro and expressed an in vivo safety/efficacy profile compatible with use as an attenuated vaccine. To determine the role of the double ORF56-57 deletion in the phenotype and to improve further the quality of the vaccine candidate, a series of deleted recombinants was produced and tested in vivo. These experiments led to the selection of a double deleted recombinant lacking ORF56 and ORF57 as a vaccine candidate. The safety and efficacy of this strain were studied using an in vivo bioluminescent imaging system (IVIS), qPCR, and histopathological examination, which demonstrated that it enters fish via skin infection similar to the wild type strain. However, compared to the parental wild type strain, the vaccine candidate replicated at lower levels and spread less efficiently to secondary sites of infection. Transmission experiments allowing water contamination with or without additional physical contact between fish demonstrated that the vaccine candidate has a reduced ability to spread from vaccinated fish to naïve sentinel cohabitants. Finally, IVIS analyses demonstrated that the vaccine candidate induces a protective mucosal immune response at the portal of entry. Thus, the present study is the first to report the rational development of a recombinant attenuated vaccine against CyHV 3 for mass vaccination of carp. We also demonstrated the relevance of the CyHV 3 carp model for studying alloherpesvirus transmission and mucosal immunity in teleost skin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.ppat.1004690DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4336323PMC
February 2015

Viral semaphorin inhibits dendritic cell phagocytosis and migration but is not essential for gammaherpesvirus-induced lymphoproliferation in malignant catarrhal fever.

J Virol 2015 Apr 14;89(7):3630-47. Epub 2015 Jan 14.

Fundamental and Applied Research in Animals and Health, Laboratory of Immunology-Vaccinology, University of Liège, Liège, Belgium

Unlabelled: Viral semaphorins are semaphorin 7A (sema7A) mimics found in pox- and herpesviruses. Among herpesviruses, semaphorins are encoded by gammaherpesviruses of the Macavirus genus only. Alcelaphine herpesvirus 1 (AlHV-1) is a macavirus that persistently infects wildebeest asymptomatically but induces malignant catarrhal fever (MCF) when transmitted to several species of susceptible ruminants and the rabbit model. MCF is caused by the activation/proliferation of latently infected T lymphocytes. Viral semaphorins have been suggested to mediate immune evasion mechanisms and/or directly alter host T cell function. We studied AlHV-sema, the viral semaphorin encoded by the A3 gene of AlHV-1. Phylogenetic analyses revealed independent acquisition of pox- and herpesvirus semaphorins, suggesting that these proteins might have distinct functions. AlHV-sema showed a predicted three-dimensional structure very similar to sema7A and conserved key residues in sema7A-plexinC1 interaction. Expression analyses revealed that AlHV-sema is a secreted 93-kDa glycoprotein expressed during the early phase of virus replication. Purified AlHV-sema was able to bind to fibroblasts and dendritic cells and induce F-actin condensation and cell retraction through a plexinC1 and Rho/cofilin-dependent mechanism. Cytoskeleton rearrangement was further associated with inhibition of phagocytosis by dendritic cells and migration to the draining lymph node. Next, we generated recombinant viruses and demonstrated that the lack of A3 did not significantly affect virus growth in vitro and did not impair MCF induction and associated lymphoproliferative lesions. In conclusion, AlHV-sema has immune evasion functions through mechanisms similar to poxvirus semaphorin but is not directly involved in host T cell activation during MCF.

Importance: Whereas most poxviruses encode viral semaphorins, semaphorin-like genes have only been identified in few gammaherpesviruses belonging to the Macavirus genus. Alcelaphine herpesvirus 1 (AlHV-1) is a macavirus carried asymptomatically by wildebeest but induces a latency-associated lymphoproliferative disease of T lymphocytes in various ruminant species, namely, malignant catarrhal fever (MCF). Viral semaphorins have been hypothesized to have immune evasion functions and/or be involved in activating latently infected T cells. We present evidence that the viral semaphorin AlHV-sema inhibits dendritic cell phagocytosis and migration to the draining lymph node, both being indispensable mechanisms for protective antiviral responses. Next, we engineered recombinant viruses unable to express AlHV-sema and demonstrated that this protein is dispensable for the induction of MCF. In conclusion, this study suggests that herpesvirus and poxvirus semaphorins have independently evolved similar functions to thwart the immune system of the host while AlHV-sema is not directly involved in MCF-associated T-cell activation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.03634-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403426PMC
April 2015

Long term-cultured and cryopreserved primordial germ cells from various chicken breeds retain high proliferative potential and gonadal colonisation competency.

Reprod Fertil Dev 2016 Apr;28(5):628-39

Embryology Unit, FARAH (Fundamental and Applied Research in Animal Health) Research Center and Faculty of Veterinary Medicine, University of Liège, 20 Boulevard de Colonster, 4000 Liège, Belgium.

When derived from chicken embryos, avian primordial germ cells (PGCs) have been reported to keep their germline-specific properties and proliferative potential even after long-term culture and genetic modifications. Few teams to date have reported such long-term expansion and engineering without differentiation of primary avian PGCs' cultures. We have developed original and robust methods that allow more than 1 year culture, expansion and cryobanking of primary cultures of PGCs without obvious effects on their biological properties, including their ability to colonise the genital ridges. Overall, 38% of embryonic samples gave rise to PGCs lines derived from three commercial layers and two Belgian endangered breeds. The lines kept their proliferative potential and their characteristic PGCs phenotype after 20 months in culture, whether or not interrupted by a cryopreservation step. All the resulting lines appeared devoid of female cells, although initially pooled from male and female embryos. Labelled PGCs from 12 long-term cultured lines colonised the genital ridges of recipient embryos. Thus, this procedure allows derivation, long-term expansion and cryobanking of primary cultures of PGCs without obvious changes to their original characteristics, providing an alternative access to applications in avian biotechnology and preservation of genetic resources.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1071/RD14194DOI Listing
April 2016