rologie i - European Congress of Virology

5 th European Congress of VirologyREF O103Human respiratory syncytial virus infection is modulated by StreptococcuspneumoniaeDuy Tien NGUYEN 1 , Rogier LOUWEN 2 , Geert VAN AMERONGEN 1 ,Ken LEMON 3 , Ad LUIJENDIJK 2 , Karin ELBERSE 4 , AlbertD.M.E. OSTERHAUS 1 , W. Paul DUPREX 5 , Rik L. DE SWART 11 Department of Viroscience, Erasmus MC, Rotterdam, THE NETHER-LANDS; 2 Department of Medical Microbiology and Infectious Diseases,Erasmus MC, Rotterdam, THE NETHERLANDS; 3 Department of Microbiology,Queen’s University of Belfast, Belfast, UNITED KINGDOM;4 National Institute of Public Health and the Environment, Bilthoven, THENETHERLANDS; 5 Department of Microbiology, Boston University, Boston,USAHuman respiratory syncytial virus (HRSV) and Streptococcus pneumoniaeare important causative agents of respiratory infections around the world.The burden for HRSV is highest in the pediatric population. Almost allinfants are infected by HRSV before the age of two years, but only asmall proportion develops severe disease. Bacterial pathogens such as S.pneumoniae can often be cultured from children hospitalized with HRSV.Interactions between viral and bacterial pathogens have been describedboth in vitro and in vivo, but causal relationships are poorly understood.S. pneumoniae has the ability to colonize humans without manifestationof disease. We have investigated whether S. pneumoniae colonizationmodulates HRSV infection, using a new recombinant (r) HRSV fromsubgroup B that expresses enhanced green fluorescent protein (EGFP),rHRSVB05EGFP. Ten S. pneumoniae serotypes obtained from colonizedchildren were obtained from a large cohort study. We have used humanB lymphocytes, primary well differentiated normal human bronchial epithelial(wd NHBE) cells with tight junctions and cilia for our in vitrostudies. Five of the ten S. pneumoniae serotypes enhanced HRSV infectionin B cells, and four of these also enhanced HRSV infections of wdNHBE cells. In ex vivo lung slice cultures obtained from uninfected cottonrats six S. pneumoniae serotypes enhanced HRSV infection. In conclusionwe show that S. pneumoniae colonization can modify HRSV infection invitro. Studies designed to investigate whether S. pneumoniae modulatesHRSV infection in cotton rats are ongoing.REF O104Gene loss and adaptation to hominoids underlie the ancient originof HIV 1Lucie ETIENNE 1 , Beatrice H. HAHN 4 , Frederick A. MATSEN 3 ,Michael EMERMAN 1,21 Division of Human Biology, Fred Hutchinson Cancer Research Center,Seattle, USA; 2 Division of Basic Sciences, Fred Hutchinson CancerResearch Center, Seattle, USA; 3 Division of Public Health Sciences,Fred Hutchinson Cancer Research Center, Seattle, USA; 4 Department ofMicrobiology, Perelman School of Medicine, University of Pennsylvania,Philadelphia, USAHIV 1 resulted from the cross species transmission of SIVcpz, a simianimmunodeficiency virus that naturally infects chimpanzees. SIVcpz, inturn, arose from the species jump and recombination of two SIV lineagesfrom old world monkeys. Lentiviral cross species transmissions are partlydriven by the capacity of viral accessory genes to adapt to antagonize hostantiviral factors. Therefore, to understand the ultimate origins of HIV 1,we analyzed the mechanisms by which the recombinant SIVcpz adaptedto hominoids.Phylogenetic analyses showed that the birth of SIVcpz was accompaniedby the complete loss of the accessory gene vpx, which, in other SIVs,is used to antagonize the host protein SAMHD1. Remarkably, the geneloss was associated with the reconstruction of the overlapping vif gene by“overprinting” using a cryptic stop codon in an alternate reading frame.The novel Vif notably acquired the conserved PPLP motif that plays a rolein HIV 1 Vif function. Overall, these events and subsequent mutationsresulted in a Vif that was more potent at restricting the hominoid versionof the antiviral protein APOBEC3G, but also led to the inability of SIVcpzto counteract the restriction factor SAMHD1. Lastly, we show that adaptationof SIV to chimpanzees facilitated the ability of Vif to antagonizehuman APOBEC3G, which was in favor of a successful viral emergencein humans.Thus, a complex set of adaptive events in response to selective pressurefrom hominoid restriction factors led to the origin of SIVcpz, andcontributed to lowering the species barrier to human infection.REF O105A novel mechanism of human cytomegalovirus evasion from restrictionfactor IFI16Valentina DELL’OSTE 1 , Deborah GATTI 1 , Francesca GUGLIESI 1 ,Marco DE ANDREA 1,2 , Matteo BIOLATTI 1 , Marta VALLINO 3 ,Manfred MARSCHALL 4 , Marisa GARIGLIO 2 , Santo LANDOLFO 11 Department of Public Health and Pediatric Sciences, University of Turin,Turin, ITALY; 2 Department of Translational Medicine, University of PiemonteOrientale “A. Avogadro”, Novara, ITALY; 3 Department of LifeSciences and Systems Biology, University of Turin, Turin, ITALY; 4 Institutefor Clinical and Molecular Virology, University of Erlangen Nuremberg,Erlangen, GERMANYIntrinsic immune mechanisms constitute an antiviral frontline defensemediated by constitutively expressed proteins termed “restriction factors”.Human Cytomegalovirus (HCMV) has evolved mechanisms to efficientlyevade the antiviral state. We have demonstrated that the DNA sensorIFI16 restricts HCMV replication by down regulating viral early and latemRNAs as well as their protein expression. Here, we show that duringearly stages of infection, HCMV induces IFI16 overexpression in primaryhuman fibroblasts (HELF). Despite this induction, continuous virus replicationindicates that somehow the virus is able to escape IFI16 restrictionactivity. Confocal microscopy revealed that, starting from 24 hours postinfection, IFI16 relocalizes from the nucleus to the virus assembly complex(AC), where it colocalizes with viral structural proteins such as gBand pp65. We demonstrate that the viral kinase pUL97 binds and phosphorylatesIFI16 thus triggering its egression from the nucleus of infectedcells. Then, the IFI16 AC complex allows IFI16 carriage in the newlyassembled virions where it is embedded in the matrix superficial layersas demonstrated by electron microscopy analysis. Altogether, these datashows a new mechanism through which HCMV is able to neutralize IFI16restriction activity by inducing first its delocalization and then its trappinginto egressing virions.REF O106Use of exome sequencing and RNAi to understand the influenceof host factors on the outcome of influenza infectionRachael WASH 1 , Deepti GURDASANI 1 , Stephanie FRANZ 1 , CarmenDIAZ SORIA 1 , Manj SANDHU 1,3 , Paul KELLAM 1,21 Wellcome Trust Sanger Institute, Cambridge, UNITED KINGDOM;2 University College London, London, UK; 3 University of Cambridge,Cambridge, UNITED KINGDOMDuring the influenza A H1N1/09 pandemic hospitalisation rates in Englandwere estimated at 4.7/100,000 population. Although many patients hadone or more pre existing comorbidities, up to 40% of patients did not andwere previously healthy. Whole virus genome sequencing of H1N1/09showed the extent of virus variation. Data suggests that whilst genomevariation occurs, and can subtly alter replication properties of the virus,it is not sufficient to account for severe or fatal influenza infection. Alterationsin human genes, such as IFITM3, that interact with the virus arehowever associated with severe influenza pathogenesis. To understand theinfluence of host genetics on virus infection we have analysed in detailS84 Virologie, Vol 17, supplément 2, septembre 2013