rologie i - European Congress of Virology

5 th European Congress of Virologya part of G gene in samples collected between 2006 and 2012 from childrenaged under 3 years in Milan, Italy. The molecular characterizationof sequences was conducted using BioEdit software. Phylogenetic treeswere constructed by Neighbor Joining method. To estimate the selectionpressures, codon specific dN and dS values were inferred using Datamonkeyserver. Potential N and O glycosylation sites were predicted usingNetNGlyc 1.0 and NetOGlyc 3.1 servers. All RSV A sequences clusteredinto two genotypes, GA2 and NA1 (similarity range: 97 99%), whereasRSV B sequences grouped into BA4 genotype (similarity range: 95 99%).Compared to the reference strains, 31 RSV A and 8 RSV B amino acidsubstitutions were identified among the sequences studied. Even if 5 positivelyselected codons were found in RSV A and one in RSV B sequences,no evidence of positive selection in both sequencing alignements emerged.Different patterns of O and N glycosilation sites were idenfided inboth groups of sequences. In conclusion, the results showed that there wasnot a variability in RSV A and B genotypes circulation in Milan duringthe study period. Although G protein showed a high genetic variability, itaccumulated almost exclusively neutral substitutions.REF 358Growth of Porcine Influenza Viruses in Differentiated RespiratoryEpithelial CellsFandan MENG 1 , Darsaniya PUNYADARSANIYA 2 , Wei YANG 1 ,Xiaofeng REN 3 , Georg HERRLER 11 Institute for Virology, University of Veterinary Medicine, Hannover, GER-MANY; 2 Institute of Virology, Mahanakorn University of Technology,Bangkok, THAILAND; 3 College of Veterinary Medicine, Northeast AgriculturalUniversity, Harbin, CHINASwine are an important host for the epidemiology and interspecies transmissionof influenza A viruses. The differentiated epithelial cells of therespiratory tract are the primary target cells for influenza virus infection.We have recently reported precision cut lung slices (PCLS) as a model systemto analyze the infection of porcine influenza viruses in their naturaltarget cells (Punaydarsaniya et al., PlosOne 6:e28429, 2011). Comparisonof a porcine virus of the H3N2 subtype with an avian virus of the H9N2subtype revealed differences in the virulence as indicated by various parameters:(i) duration of the growth cycle, (ii) amount of infectious virusreleased into the supernatant, and (iii) extent of the ciliostatic effect. Herewe compared five porcine viruses of the three subtypes currently prevalentin the swine populations (H3N2, H1N1, H1N2). The data collected werecompared with the pathogenicity of the viruses determined in pigs. In thisway, we show which of the above parameters is the best indicator of thepathogenicity of porcine influenza viruses.REF 359The adaptation of avian influenza viruses to the respiratory epitheliumof pigsWei YANG 1 , Fandan MENG 1 , Darsaniya PUNYADARSANIY 2 ,Markus HOFFMANN 1 , Juergen STECH 3 , Dirk HOEPER 3 , MartinBEER 3 , Christel SCHWEGMANN WESSELS 1 , Xiaofeng REN 4 , GeorgHERRLER 11 Institute of Virology, University of Veterinary Medicine, Hannover, GER-MANY; 2 Institute of Virology, Mahanakorn University of Technology,Bangkok, THAILAND; 3 Friedrich Loeffler Institut, Bundesforschungsinstitutfür Tiergesundheit, Greifswald, GERMANY; 4 College of VeterinaryMedicine, Northeast Agricultural University, Harbin, CHINAPigs are an important host for influenza A viruses and may play a crucialrole in the interspecies transmission. To analyze the infection byinfluenza viruses, we have established precision cut lung slices (PCLS)from the porcine lung as a culture system for differentiated respiratoryepithelial cells. In PCLS, the differentiated epithelial cells are maintainedin their original setting. As differentiated repiratory epithelial cells are theprimary target cells for influenza virus infections, PCLS provide an interestingsystem to analyze the adaptation of avian influenza viruses to therespiratory epithelium of pigs. Avian influenza viruses of the H9N2 subtypewere subjected to several passages in PCLS. Adaptation of the avianviruses to growth in porcine cells was evident in a shortening of the growthcycle. Sequence analysis revealed that few amino acid changes occurredduring the different virus passages. The importance of the individual mutationsis currently analyzed by generating recombinant viruses that containthe respective mutated proteins. Our study will help to understand theprocesses involved in the adaptation of H9N2 influenza viruses to newhosts.Virologie, Vol 17, supplément 2, septembre 2013S219