Project description:CpG 1826 binds to Toll-like receptor (TLR)9, whereas influenza virus PR8 activates pDC via TLR7. Differential stimulation of pDCs is expected to result in unique activation mechanism(s) leading to a different phenotypically and functionally matured pDC We used microarrays to detail the global programme of gene expression underlying the maturation process of pDC activated with CpG 1826 and influenza virus PR8. We identified a distinct expression profile of upregulated immunomediators. Keywords: time course
Project description:CpG 1826 binds to Toll-like receptor (TLR)9, whereas influenza virus PR8 activates pDC via TLR7. Differential stimulation of pDCs is expected to result in unique activation mechanism(s) leading to a different phenotypically and functionally matured pDC; We used microarrays to detail the global programme of gene expression underlying the maturation process of pDC activated with CpG 1826 and influenza virus PR8. We identified a distinct expression profile of upregulated immunomediators. Experiment Overall Design: Sorted pDCs were cultured for 1h and 4hs in medium control or with 5 µg/ml CpG 1826 or 300 HAU/ml purified influenza A/PR/8 virus. The first experiment (e1) included pDC in media and stimulated with CpG for 4h. In two other independent experimental batches (e2 and e3), we obtained samples of sorted pDC cultured in medium alone (med), and with CpG or PR8 (flu) for 1h and 4h. RNA extraction was performed using the RNeasy Kit (Qiagen) and hybridization on Affymetrix microarrays was performed using standard protocols. We sought to obtain homogeneous populations of pDCs at different time points under defined activation conditions in order to decipher the temporal resolution of expression profiles during the process of their maturation.
Project description:DBA/2J (D2) and C57BL/6J mice (B6) were infected intra-nasally with 2x10^3 FFU of influenza A H1N1 (PR8) virus. Lungs were collected from mock-infected controls or at day 1,2,3,4 post infection. Expression data were obtained from three independent experiments. We infected a highly susceptible mouse strain (D2) and a resistant strain (B6) with PR8 and performed a genome-wide expression analysis. We found genes expressed in lung epithelium that were specifically down-regulated in D2 mice, whereas a cluster of genes on chromosome 3 was only down-regulated in B6. In both mouse strains, chemokines, cytokines and interferon-response genes were up-regulated, indicating that the main innate immune defense pathways were activated. However, many immune response genes were up-regulated in D2 much stronger than in B6, and several immune response genes were exclusively regulated in D2. Thus, susceptible D2 mice showed a hyper-inflammatory response. This response is similar to infections with highly pathogenic influenza virus and may serve as a paradigm for a hyper-inflammatory host response to influenza A virus.
Project description:Plasmacytoid dendritic cells (pDCs) can rapidly produce interferons and other soluble factors in response to extracellular viruses or virus mimics such as CpG-containing DNA. pDCs can also recognize live cells infected with certain RNA viruses, but the relevance and functional consequences of such recognition remain unclear. We studied the response of primary DCs to the prototypical persistent DNA virus, the human cytomegalovirus (CMV). Human pDCs responded poorly to free CMV but strongly to live CMV-infected fibroblasts, in a process that involved integrin-mediated adhesion, transfer of viral DNA to pDCs and its recognition through TLR9. Compared to transient polyfunctional responses to CpG or free influenza virus, pDC response to CMV-infected cells was long-lasting, dominated by the production of type I (IFN-I) and type III (IFN-III) interferons, and lacked diversification into functionally distinct populations. Similarly, pDC activation by influenza-infected lung epithelial cells was highly efficient, prolonged and dominated by interferon production. Prolonged pDC activation by CMV-infected cells facilitated the activation of natural killer cells that are critical for CMV control. Finally, patients with CMV viremia harbored phenotypically activated pDCs and increased levels of IFN-I and IFN-III in circulation. Thus, recognition of live infected cells is a common mechanism of virus detection by pDCs that elicits a unique antiviral response program.
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:To further understand the molecular pathogenesis of the 2009 pandemic H1N1 influenza virus infection, we profiled cellular miRNAs of lung tissue from BALB/c mice infected with influenza virus BJ501 and a mouse-adapted influenza virus A/Puerto Rico/8/34 (H1N1)(PR8) as a comparison.
Project description:Macrophages were infected with low (PR8) and high pathogenic influenza viruses (FPV and H5N1). To our surprise a genome-wide comparative systems biology approach revealed that in contrast PR8 infections with HPAIV H5N1 and FPV result in a reduced immune response of human macrophages contradicting a primary role of this cell type for the cytokine storm. Our data point to a viral strategy of HPAIV to bypass a major amplifier of the initial local inflammatory response thereby hampering antiviral effector mechanisms and facilitating virus spreading and systemic disease. Macrophages were infected with low (PR8) and high pathogenic influenza viruses (FPV and H5N1)
Project description:To further understand the molecular pathogenesis of the 2009 pandemic H1N1 influenza virus infection, we profiled cellular miRNAs of lung tissue from BALB/c mice infected with influenza virus BJ501 and a mouse-adapted influenza virus A/Puerto Rico/8/34 (H1N1)(PR8) as a comparison. Five groups of mice were selected, and three of each group were used to profile the miRNA, two were in case for unqualified RNA extraction. Whole lungs from mice infected by BJ501 or PR8 were harvested on 2,5 days post infection (dpi), and compared with lung samples from 5 uninfected mice.
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.
