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The association of the SH protein with respiratory syncytial virus (RSV) particles was examined in HEp2 cells and human ciliated nasal epithelial cells. Imaging of infected cells demonstrated the presence of the SH protein in virus filaments, and analysis of purified RSV particles revealed a SH protein species whose size was consistent with the glycosylated SH protein. Although the SH protein was detected in virus filaments it was not required for virus filament formation. Analysis of RSV-infected ciliated cells also revealed that the SH protein was trafficked into the cilia, and this correlated with reduced cilia density on these cells. Reduced cilia loss was not observed on ciliated cells infected with a RSV isolate that failed to express the SH protein. These data provide direct evidence that the SH protein is trafficked into virus particles, and suggests that the SH protein may also promote cilia dysfunction on nasal epithelial cells.

International audience; Despite increasing control measures, numerous parasitic and infectious diseases are emerging, re-emerging or causing recurrent outbreaks particularly in Asia and the Pacific region, a hot spot of both infectious disease emergence and biodiversity at risk. We investigate how biodiversity affects the distribution of infectious diseases and their outbreaks in this region, taking into account socio-economics (population size, GDP, public health expenditure), geography (latitude and nation size), climate (precipitation, temperature) and biodiversity (bird and mammal species richness, forest cover, mammal and bird species at threat). We show, among countries, that the overall richness of infectious diseases is positively correlated with the richness of birds and mammals, but the number of zoonotic disease outbreaks is positively correlated with the number of threatened mammal and bird species and the number of vector-borne disease outbreaks is negatively correlated with forest cover. These results suggest that, among countries, biodiversity is a source of pathogens, but also that the loss of biodiversity or its regulation, as measured by forest cover or threatened species, seems to be associated with an increase in zoonotic and vector-borne disease outbreaks.

The influenza A genome replication and gene transcription are mediated by polymerase complex composed of three polymerase subunits PA, PB1 and PB2. This polymerase complex is also essential for host adaptation and pathogenesis. To characterize the polymerase complex of 2009 pandemic H1N1 (pH1N1) and low pathogenic avian (LPAI) H5N2 influenza viruses, monoclonal antibodies (mAbs) against these complexes are essential. Therefore, we have challenged mice with purified soluble PA protein (pH1N1/471 and H5N2/F118 strains), insoluble PB2 and PB1 proteins (pH1N1/471 strain). Then, mAbs directed against PA subunit of both strains and PB2 subunit of 2009 pH1N1 strain were successfully generated, while mAb against PB1 subunit was not successful at fusion stage for two attempts. Interestingly, two mAbs-PA(9F5 and 2E2) against pH1N1/471 strain recognized PA protein in virus-infected cells with different staining patterns, which may be explained by their different epitope recognition. In addition, smaller protein products (PA*) were identified by 9F5 in recombinant protein expression, virus-infected cells and mature virus particles. We proved the PA* are PA related and demonstrated the first evidence of their association with the RNP complex. Similar to PA*, PB2* was also revealed by mAb-PB2(4G3), but in the virions, suggesting that PB2* was not virus-associated. However, significance of PB2* remained unclear and it needs further investigation. For the functional analysis of viral polymerase complex, NP and three polymerase subunits of four influenza virus strains have been successfully cloned using a mammalian expression system. H1N1/WSN polymerase complex was found to be the most active than polymerase complexes of other strains tested. In our gene reassortment study, a single reassortant bearing a human-origin PA or PB2 subunit against an avian polymerase background could overcome the host range barrier of avian polymerase in human 293T cells, indicating the PA or PB2 as a major determinant of species tropism and pathogenicity. Again in our RNAi study, potent in vitro inhibition of virus replication was achieved with eight siRNAs against NP and polymerase genes of LPAI H5N2 virus as observed by reduction in mRNA levels, protein expressions and virus titers. DOCTOR OF PHILOSOPHY (SBS)