Project description:The determinants of influenza transmission remain poorly understood. Swine influenza viruses preferentially attach to receptors found in the upper airways; however, most swine influenza viruses fail to transmit efficiently from swine to humans, and from human-to-human. The pandemic 2009 H1N1 (H1N1pdm) virus was a rare exception of a swine virus that acquired efficient transmissibility from human-to-human, and is reflected in efficient respiratory droplet transmission in ferrets. We hypothesize that virus-induced host responses in the upper airways correlate with airborne transmission in ferrets. To address this question, we used the H1N1pdm virus and swine influenza A/swine/Hong Kong/201/2010 (HK201) virus that has comparable titre in the ferret nasopharynx, but it exhibits differential transmissibility in ferrets via respiratory droplet route. We performed a transcriptomic analysis of tissues from the upper and lower respiratory tract from ferrets infected with either H1N1pdm or HK201 viruses using ferret-specific Agilent oligonucleotide arrays. We found differences in the kinetics of the innate immune response elicited by these two viruses that varied across tissues.
Project description:In recent years, the roles of microRNAs playing in the regulation of influenza viruses replication caused researchers' much attenion. However, much work focused on the interactions between human, mice or chicken microRNAs with human or avian influenza viruses rather than the interactions of swine microRNAs and swine influenza viruses. To investigate the roles of swine microRNAs playing in the regulation of swine influenza A virus replication, the microRNA microarray was performed to identify which swine microRNAs were involved in swine H1N1/2009 influenza A virus infection.
Project description:Occasional transmission of highly pathogenic avian H5N1 influenza viruses to humans causes severe pneumonia with high mortality. To better understand the mechanisms via which H5N1 viruses induce severe disease in humans, we infected cynomolgus macaques with six different H5N1 strains isolated from human patients and compared their pathogenicity and the global host responses to the virus infection. Although all H5N1 viruses replicated in the respiratory tract, there was substantial heterogeneity in their replicative ability and in the disease severity induced, which ranged from asymptomatic to fatal. A comparison of global gene expression between severe and mild disease cases indicated that interferon-induced up-regulation of genes related to innate immunity, apoptosis, and antigen processing/presentation in the early phase of infection was limited in severe disease cases, although interferon expression was up-regulated in both severe and mild cases. Furthermore, co-expression analysis of microarray data, which reveals the dynamics of host responses during the infection, demonstrated that the limited expression of these genes early in infection led to a failure to suppress virus replication and to the hyperinduction of genes related to immunity, inflammation, coagulation, and homeostasis in the late phase of infection, resulting in a more severe disease. Our data suggest that the attenuated interferon-induced activation of innate immunity, apoptosis, and antigen presentation in the early phase of H5N1 virus infection leads to subsequent severe disease outcome. Bronchial brushes for microarray studies were obtained from female cynomolgus macaques infected with influenza viruses. Three animals per group were inoculated with one of three H5N1 influenza viruses (VN3028II, VN30259 or VN3040). The early phase of infection refers to timepoints Pre (prior to infection), 1, and 3 days post-infection. The late phase of infection refers to days 5 and 7 post-infection. Samples collected prior to infection (labeled as Pre) served as control data for each infection group.
Project description:Highly pathogenic influenza virus inhibit Inflammatory Responses in Monocytes via Activation of the Rar-Related Orphan Receptor Alpha (RORalpha). Low (PR8) and high pathogenic influenza viruses (FPV and H5N1) were used. Monocytes were infected with low (PR8) and high pathogenic influenza viruses (FPV and H5N1)
Project description:Influenza virus transmission between mothers and nursing-infants has not been investigated although mothers and infants often develop severe disease. Ferrets are considered the most appropriate model for influenza studies. We investigated influenza transmission in infant and nursing-mother ferrets. Influenza infected infants transmitted virus to mother mammary glands leading to live virus excretion in milk and influenza virus positive mammary gland epithelial cells. Global gene expression analysis showed down-regulation of milk production and induction of breast involution and oncogenesis pathways. Our results provide insight into influenza transmission between mothers and infants which may impact fields of infectious disease, maternal/infant health and neoplasm etiology.
Project description:Influenza virus transmission between mothers and nursing-infants has not been investigated although mothers and infants often develop severe disease. Ferrets are considered the most appropriate model for influenza studies. We investigated influenza transmission in infant and nursing-mother ferrets. Influenza infected infants transmitted virus to mother mammary glands leading to live virus excretion in milk and influenza virus positive mammary gland epithelial cells. Global gene expression analysis showed down-regulation of milk production and induction of breast involution and oncogenesis pathways. Our results provide insight into influenza transmission between mothers and infants which may impact fields of infectious disease, maternal/infant health and neoplasm etiology.
Project description:Influenza A virus (IAV) pandemics result from interspecies transmission events within the avian reservoir and further into mammals including humans. Investigating the molecular basis for virus–host interactions enabling this process is vital to understand zoonotic IAV spread. Receptor incompatibility has been suggested to limit zoonotic IAV transmission from the wild bird reservoir as well as between different bird species. Using glycoproteomics, we have studied the repertoires of expressed glycan structures with focus on putative receptors for IAV in mallards, chickens and tufted ducks; three bird species with different roles in the zoonotic ecology of IAV. The methodology used could not only pinpoint specific glycan structures to the specific glycosylation sites of identified glycoproteins but could also be used to successfully discriminate α2,3- from α2,6-linked terminal sialic acids by careful analysis of oxonium ions released from glycopeptides during MS/MS (MS2), and MS/MS/MS (MS3). Our analysis clearly demonstrated that all three bird species can produce complex α2,3 and α2,6-linked Neu5Ac N-glycans including α2,3-linked sialyl Lewis structures, as well as both N- and O- glycans terminated with both α2,3 and α2,6-linked Neu5Ac. Furthermore, we reveal many similarities in the repertoires of expressed receptors both between the bird species investigated and to previously published data from pigs and humans. Our findings of sialylated glycan structures previously anticipated to be mammalian specific in all three bird species have major implications for our understanding of the role of receptor incompatibility in interspecies transmission of IAV.
Project description:Zoonotic influenza A viruses of avian origin can cause severe disease in individuals, or even global pandemics, and thus pose a threat to human populations. Waterfowl and shorebirds are believed to be the reservoir for all influenza A viruses, but this has recently been challenged by the identification of novel influenza A viruses in bats. The major bat influenza A virus envelope glycoprotein, haemagglutinin, does not bind the canonical influenza A virus receptor, sialic acid or any other glycan, despite its high sequence and structural homology with conventional haemagglutinins. This functionally uncharacterized plasticity of the bat influenza A virus haemagglutinin means the tropism and zoonotic potential of these viruses has not been fully determined. Here we show, using transcriptomic profiling of susceptible versus non-susceptible cells in combination with genome-wide CRISPR-Cas9 screening, that the major histocompatibility complex class II (MHC-II) human leukocyte antigen DR isotype (HLA-DR) is an essential entry determinant for bat influenza A viruses. Genetic ablation of the HLA-DR α-chain rendered cells resistant to infection by bat influenza A virus, whereas ectopic expression of the HLA-DR complex in non-susceptible cells conferred susceptibility. Expression of MHC-II from different bat species, pigs, mice or chickens also conferred susceptibility to infection. Notably, the infection of mice with bat influenza A virus resulted in robust virus replication in the upper respiratory tract, whereas mice deficient for MHC-II were resistant. Collectively, our data identify MHC-II as a crucial entry mediator for bat influenza A viruses in multiple species, which permits a broad vertebrate tropism.