rologie i - European Congress of Virology

5 th European Congress of VirologyThursday 12 th September 2013, 8h30 – 10h30WORKSHOP 5: “VIRAL (IMMUNO)PATHOGENESIS”Chairpersons: Branka HORVAT (Lyon, FRANCE)& Thomas MERTENS (Ulm, GERMANY)Room Prestige Gratte-CielEpidemiological studies relate influenza infection with vascular diseases.The hypothesis that influenza infection has procoagulant effects on humanshas been investigated in experimental animal models. However, thesestudies used animal models only susceptible to mouse adapted influenzaviruses and therefore results are hard to translate to human infection.Since ferrets are good models for human influenza we used ferrets tostudy and compare effects on blood coagulation in a controlled setting.Ferrets were inoculated with either a mock, seasonal, pandemicor avian influenza strain. All influenza infected animals showed significantalterations in clotting times compared to mock inoculated ferrets.Specifically on day 4 post infection, we observed a four second rise inboth prothombin time and activated partial thromboplastin time. D Dimerconcentrations were increased in all 3 influenza groups with the highestconcentrations in the pandemic influenza group. Von Willebrand factoractivity increased early in the infection suggesting endothelial cellactivation. Mean thrombin antithrombin complex levels were raised inboth pandemic and avian influenza infected ferrets in the first days afterinfection. At the tissue level, fibrin staining showed intracapillary fibrindeposition especially in H5N1 infected ferrets. To our knowledge thisis the first study that visualized hemostatic alterations in influenza virusinfection in an animal model resembling human disease both at the circulatoryand tissue level. These alterations may be the result of consumptivecoagulopathy.KEYNOTE:Vaccine induced immunity to influenza: Some considerationsGuus F. RIMMELZWAANDepartment of Viroscience, Erasmus Medical Center, Rotterdam, THENETHERLANDSFor the induction of protective immunity against seasonal influenza, commonlyinactivated vaccine preparations are used. These vaccines are highlyefficacious provided that the virus strains used in the vaccine antigenicallymatch the epidemic strains. The use of these inactivated seasonalinfluenza vaccines afford little or no protection against antigenicallydistinct influenza viruses, including potentially pandemic influenza Aviruses of novel subtypes and even may hamper the induction the protectiveimmunity against pandemic influenza, so-called heterosubtypicimmunity, otherwise induced by natural infection with seasonal influenzaviruses. Ideally, influenza vaccines induce more broadly protective immunityagainst viruses of various subtypes. Recent research aims at definingconserved viral proteins or conserved regions of viral proteins as targets forcross-protective humoral and cellular immune responses to aid the developmentof more broadly protective vaccines. Especially immunologicallynaïve individuals such as children