title: Role of gB and pUS3 in Equine Herpesvirus 1 Transfer between Peripheral Blood Mononuclear Cells and Endothelial Cells: a Dynamic In Vitro Model.
abstract: Infected peripheral blood mononuclear cells (PBMC) effectively transport equine herpesvirus type 1 (EHV-1), but not EHV-4, to endothelial cells (EC) lining the blood vessels of the pregnant uterus or central nervous system, a process that can result in abortion or myeloencephalopathy. We examined, using a dynamic in vitro model, the differences between EHV-1 and EHV-4 infection of PBMC and PBMC-EC interactions. In order to evaluate viral transfer between infected PBMC and EC, cocultivation assays were performed. Only EHV-1 was transferred from PBMC to EC, and viral glycoprotein B (gB) was shown to be mainly responsible for this form of cell-to-cell transfer. For addressing the more dynamic aspects of PBMC-EC interaction, infected PBMC were perfused through a flow channel containing EC in the presence of neutralizing antibodies. By simulating capillary blood flow and analyzing the behavior of infected PBMC through live fluorescence imaging and automated cell tracking, we observed that EHV-1 was able to maintain tethering and rolling of infected PBMC on EC more effectively than EHV-4. Deletion of US3 reduced the ability of infected PBMC to tether and roll compared to that of cells infected with parental virus, which resulted in a significant reduction in virus transfer from PBMC to EC. Taking the results together, we conclude that systemic spread and EC infection by EHV-1, but not EHV-4, is caused by its ability to infect and/or reprogram mononuclear cells with respect to their tethering and rolling behavior on EC and consequent virus transfer.
  
  
  OBJECTIVE
  EHV-1 is widespread throughout the world and causes substantial economic losses through outbreaks of respiratory disease, abortion, and myeloencephalopathy. Despite many years of research, no fully protective vaccines have been developed, and several aspects of viral pathogenesis still need to be uncovered. In the current study, we investigated the molecular mechanisms that facilitate the cell-associated viremia, which is arguably the most important aspect of EHV-1 pathogenesis. The newly discovered functions of gB and pUS3 add new facets to their previously reported roles. Due to the conserved nature of cell-associated viremia among numerous herpesviruses, these results are also very relevant for viruses such as varicella-zoster virus, pseudorabies virus, human cytomegalovirus, and others. In addition, the constructed mutant and recombinant viruses exhibit potent in vitro replication but have significant defects in certain stages of the disease course. These viruses therefore show much promise as candidates for future live vaccines.
authors.affiliation: Institut für Virologie, Robert von Ostertag-Haus, Zentrum für Infektionsmedizin, Freie Universität Berlin, Berlin, Germany.
authors.forename: Bart
authors.initials: B
authors.lastname: Spiesschaert
authors.affiliation: Institute of Biology/Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Goldenbogen
authors.affiliation: Institut für Virologie, Robert von Ostertag-Haus, Zentrum für Infektionsmedizin, Freie Universität Berlin, Berlin, Germany.
authors.forename: Selina
authors.initials: S
authors.lastname: Taferner
authors.affiliation: Institute of Biology/Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schade
authors.affiliation: Institute of Animal Breeding and Genetics, University of Hohenheim, Stuttgart, Germany.
authors.forename: Medhat
authors.initials: M
authors.lastname: Mahmoud
authors.affiliation: Institute of Biology/Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany.
authors.forename: Edda
authors.initials: E
authors.lastname: Klipp
authors.affiliation: Institut für Virologie, Robert von Ostertag-Haus, Zentrum für Infektionsmedizin, Freie Universität Berlin, Berlin, Germany.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Osterrieder
authors.affiliation: Institut für Virologie, Robert von Ostertag-Haus, Zentrum für Infektionsmedizin, Freie Universität Berlin, Berlin, Germany Department of Virology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt wfazab@zedat.fu-berlin.de.
authors.forename: Walid
authors.initials: W
authors.lastname: Azab
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002449:Cell Aggregation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000821:virology*; D005453:Fluorescence; D006566:Herpesviridae Infections / Q000503:physiopathology*; D004861:Herpesvirus 1, Equid / Q000502:physiology*; D023141:Herpesvirus 4, Equid / Q000502:physiology*; D006736:Horses; D066298:In Vitro Techniques; D007963:Leukocytes, Mononuclear / Q000821:virology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D018709:Statistics, Nonparametric; D014759:Viral Envelope Proteins / Q000378:metabolism*; D053586:Virus Internalization
chemical_list: D014759:Viral Envelope Proteins; C040495:glycoprotein B, Simplexvirus; D017346:Protein Serine-Threonine Kinases