Chemotactic antiviral cytokines promote infectious apical entry of human adenovirus into polarized epithelial cells

Mucosal epithelia provide strong barriers against pathogens. For instance, the outward facing apical membrane of polarized epithelial cells lacks receptors for agents, such as hepatitis C virus, herpesvirus, reovirus, poliovirus or adenovirus. In addition, macrophages eliminate pathogens from the luminal space. Here we show that human adenovirus type 5 engages an antiviral immune response to enter polarized epithelial cells. Blood-derived macrophages co-cultured apically on polarized epithelial cells facilitate epithelial infection. Infection also occurs in the absence of macrophages, if virus-conditioned macrophage-medium containing the chemotactic cytokine CXCL8 (interleukin-8), or recombinant CXCL8 are present. In polarized cells, CXCL8 activates a Src-family tyrosine kinase via the apical CXCR1 and CXCR2 receptors. This activation process relocates the viral co-receptor ανβ3 integrin to the apical surface, and enables apical binding and infection with adenovirus depending on the primary adenovirus receptor CAR. This paradigm may explain how other mucosal pathogens enter epithelial cells

Opacity effects in a solid-density aluminium plasma created by photo-excitation with an X-ray laser

The intensities within the focal spots of the output of recently developed X-ray sources based on free-electron-laser (FEL) technology are so great that atoms within the focal region can potentially absorb several photons during the few tens of femtosecond X-ray pulse. Furthermore, the duration of the FEL X-ray pulse is comparable to the Auger decay times of inner-shell holes created by the X-rays themselves. We report here how such a scenario can lead to opacity broadening of the fluorescence radiation emitted by the hot, dense plasma, which is created as a result of the X-radiation focussed onto a solid target, and in particular present calculations of the broadening of the Kα emission in a solid-density aluminium target, produced when the FEL photon energy is tuned below the Al K-edge, but is resonant with the Kα transition. © 2014 Elsevier B.V