Many human cells can sense the presence of exogenous DNA during infection though the cytosolic DNA receptor cyclic GMP-AMP synthase (cGAS), which produces the second messenger cyclic GMP-AMP (cGAMP). Other putative DNA receptors have been described, but whether their functions are redundant, tissue-specific or integrated in the cGAS-cGAMP pathway is unclear. Here we show that interferon-γ inducible protein 16 (IFI16) cooperates with cGAS during DNA sensing in human keratinocytes, as both cGAS and IFI16 are required for the full activation of an innate immune response to exogenous DNA and DNA viruses. IFI16 is also required for the cGAMP-induced activation of STING, and interacts with STING to promote STING phosphorylation and translocation. We propose that the two DNA sensors IFI16 and cGAS cooperate to prevent the spurious activation of the type I interferon response.

We have produced an Fc conjugate of colony-stimulating factor (CSF) 1 with an improved circulating half-life. CSF1-Fc retained its macrophage growth-promoting activity, and did not induce proinflammatory cytokines in vitro. Treatment with CSF1-Fc did not produce adverse effects in mice or pigs. The impact of CSF1-Fc was examined using the Csf1r-enhanced green fluorescent protein (EGFP) reporter gene in MacGreen mice. Administration of CSF1-Fc to mice drove extensive infiltration of all tissues by Csf1r-EGFP positive macrophages. The main consequence was hepatosplenomegaly, associated with proliferation of hepatocytes. Expression profiles of the liver indicated that infiltrating macrophages produced candidate mediators of hepatocyte proliferation including urokinase, tumor necrosis factor, and interleukin 6. CSF1-Fc also promoted osteoclastogenesis and produced pleiotropic effects on other organ systems, notably the testis, where CSF1-dependent macrophages have been implicated in homeostasis. However, it did not affect other putative CSF1 targets, notably intestine, where Paneth cell numbers and villus architecture were unchanged. CSF1 has therapeutic potential in regenerative medicine in multiple organs. We suggest that the CSF1-Fc conjugate retains this potential, and may permit daily delivery by injection rather than continuous infusion required for the core molecule.

Recent reports of natural paratuberculosis (or Johne's disease) in rabbits, foxes, and stoats has focused debate on the presence and importance of wildlife reservoirs in the epidemiology of this disease. This paper describes an extensive study investigating 18 nonruminant wildlife species for evidence of paratuberculosis. Using both culture and histopathological analysis, fox, stoat, weasel, crow, rook, jackdaw, rat, wood mouse, hare, and badger were found to harbor Mycobacterium avium subsp. paratuberculosis, the causative organism of paratuberculosis, suggesting that the epidemiology of this disease is more complex than previously realized.

Previously, we demonstrated that frequencies of CpG and UpA dinucleotides profoundly influence the replication ability of echovirus 7 (Tulloch et al., 2014). Here, we show that that influenza A virus (IAV) with maximised frequencies of these dinucleotides in segment 5 showed comparable attenuation in cell culture compared to unmodified virus and a permuted control (CDLR). Attenuation was also manifested in vivo, with 10-100 fold reduced viral loads in lungs of mice infected with 200PFU of CpG-high and UpA-high mutants. However, both induced powerful inflammatory cytokine and adaptive (T cell and neutralising antibody) responses disproportionate to their replication. CpG-high infected mice also showed markedly reduced clinical severity, minimal weight loss and reduced immmunopathology in lung, yet sterilising immunity to lethal dose WT challenge was achieved after low dose (20PFU) pre-immunisation with this mutant. Increasing CpG dinucleotide frequencies represents a generic and potentially highly effective method for generating safe, highly immunoreactive vaccines.DOI: http://dx.doi.org/10.7554/eLife.12735.001

Prolonged anti-CSF1R prevents age-dependent bone loss in female mice, without the phenotypic consequences of the CSF1R and CSF1 null mutations.

No abstract

The cleavage and packaging of newly synthesized herpesvirus DNA is a highly conserved process occurring late in viral replication. During herpesvirus infection, double-stranded viral DNA genomes accumulate in cell nuclei as head-to-tail concatemers which are subsequently cleaved into single genome lengths and packaged into preformed viral capsids (reviewed in reference 19). Six genes of herpes simplex virus type 1 (HSV-1) are known to be essential for this process, namely, U L 6, U L 15, U L 17, U L 28, U L 32, and U L 33. In cells infected with viruses individually lacking these genes, capsids appear normal and are readily detected, but viral DNA is neither cleaved nor packaged (2,3,5,9,12,25,26,30,31,35,37,(40)(41)(42)44).The cleavage and packaging process of herpesviruses is believed to be similar to that employed by double-stranded DNA bacteriophages; consequently, it is useful to consider the mechanisms used by these bacteriophages as a model for the cleavage and packaging events employed by herpesviruses. Such models propose a central role for the viral "terminase," a complex of at least two proteins that (i) binds the viral DNA and links it with the empty viral capsid (HSV-1) or prohead (bacteriophages); (ii) cleaves the viral DNA at precise internal sites, resulting in the separation of unit-length genomes from concatameric DNA; and (iii) hydrolyzes ATP, providing the energy required to drive the DNA into the capsid (reviewed in reference 10). With this paradigm in mind, efforts have been expended to identify herpesvirus gene products that perform functions expected of the viral terminase, especially DNA binding, ATP hydrolysis, and at least transient association with capsids.There is a growing body of both direct and indirect evidence suggesting that the U L 15 and U L 28 gene products comprise two subunits of the HSV-1 terminase. The U L 28 gene product has been shown to bind specifically to the HSV-1 DNA sequence pac1, which is found in the a sequence of the genome and is known to be essential for the generation of correct genomic termini (4, 38). The U L 15 protein has been hypothesized to hydrolyze ATP, based on limited homology with a putative nucleotide binding motif comprised of Walker boxes A and B within gp17, the larger subunit of the T4 bacteriophage terminase (15). Although the ATPase activity of the U L 15 protein has yet to be directly demonstrated, a mutation within the Walker box precludes viral DNA cleavage and packaging (46). The U L 28 and U L 15 proteins have also been shown to interact in transient-expression assays (1,22,23,45) and in coimmunoprecipitation experiments using nuclear extracts of infected cells (23).This paper describes the isolation of a protein complex consisting of the U L 28, U L 15, and U L 33 proteins by immunoprecipitation from lysates of infected cells. This suggests for the first time that the U L 33 gene product may function as a third subunit of the putative viral terminase. MATERIALS AND METHODS Cells and viruses.Vero and HEp-2 cells and transformed cell l...

Paratuberculosis (Johne's disease) was long considered only a disease of ruminants. Recently non-ruminant wildlife species have been shown to harbor Mycobacterium avium subsp. paratuberculosis, the causative organism of paratuberculosis. We review the known non-ruminant wildlife host range of M. avium subsp. paratuberculosis and consider their role in the epidemiology of paratuberculosis in domestic ruminant livestock. Mycobacterium avium subsp. paratuberculosis has been isolated from lagomorph, canid, mustelid, corvid, and murid species. In agricultural environments domestic ruminants may contact wildlife and/or their excreta when grazing or feeding on farm-stored feed contaminated with wildlife feces, opening up the possibility of inter-species transmission. Of the wildlife species known to harbor M. avium subsp. paratuberculosis in Scotland, the rabbit is likely to pose the greatest risk to grazing livestock. Paratuberculosis in domestic ruminants is a notoriously difficult disease to control; the participation of non-ruminant wildlife in the epidemiology of the disease may partially account for this difficulty.