BackgroundType I interferons are major players against viral infections and mediate their function by the induction of Interferon regulated genes (IRGs). Recently, it became obvious that these cytokines have a multitude of additional functions. Due to the unique features of the chickens’ immune system, available data from mouse models are not easily transferable; hence we performed an extensive analysis of chicken IRGs.ResultsA broad database search for homologues to described mammalian IRGs (common IRGs, cIRGs) was combined with a transcriptome analysis of spleen and lung at different time points after application of IFNα. To apply physiological amounts of IFN, half-life of IFN in the chicken was determined. Interestingly, the calculated 36 min are considerably shorter than the ones obtained for human and mouse. Microarray analysis revealed many additional IRGs (newly identified IRGs; nIRGs) and network analysis for selected IRGs showed a broad interaction of nIRGs among each other and with cIRGs. We found that IRGs exhibit a highly tissue and time specific expression pattern as expression quality and quantity differed strongly between spleen and lung and over time. While in the spleen for many affected genes changes in RNA abundance peaked already after 3 h, an increasing or plateau-like regulation after 3, 6 and 9 h was observed in the lung.ConclusionsThe induction or suppression of IRGs in chickens is both tissue and time specific and beside known antiviral mechanisms type I IFN induces many additional cellular functions. We confirmed many known IRGs and established a multitude of so far undescribed ones, thus providing a large database for future research on antiviral mechanisms and additional IFN functions in non-mammalian species.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3641-6) contains supplementary material, which is available to authorized users.

The expression level of acute phase proteins (APPs) mirrors the health status of an individual. In human medicine, C-reactive protein (CRP), and other members of the pentraxin family are of significant relevance for assessing disease severity and prognosis. In chickens, however, which represent the most common livestock species around the world, no such marker has yet gained general acceptance. The aim of this study was therefore, to characterize chicken pentraxin 3 (chPTX3) and to evaluate its applicability as a general marker for inflammatory conditions. The mammalian and chicken PTX3 proteins were predicted to be similar in sequence, domain organization and polymeric structure. Nevertheless, some characteristics like certain sequence sections, which have varied during the evolution of mammals, and species-specific glycosylation patterns, suggest distinct biological functions. ChPTX3 is constitutively expressed in various tissues but, interestingly, could not be found in splenic tissue samples without stimulation. However, upon treatment with lipopolysaccharide (LPS), PTX3 expression in chicken spleens increased to 95-fold within hours. A search for PTX3 reads in various publicly available RNA-seq data sets of chicken spleen and bursa of Fabricius also showed that PTX3 expression increases within days after experimental infection with viral and bacterial pathogens. An experimental infection with avian pathogenic E.coli and qPCR analysis of spleen samples further established a challenge dose-dependent significant up-regulation of chPTX3 in subclinically infected birds of up to over 150-fold as compared to untreated controls. Our results indicate the potential of chPTX3 as an APP marker to monitor inflammatory conditions in poultry flocks.

14Varicella-Zoster virus (VZV) causes chickenpox and shingles. Although infection is 15 associated with severe morbidity in some individuals, the molecular mechanisms that 16 determine innate immune responses remain poorly defined. We found that the 17 cGAS/STING DNA sensing pathway was critically required for type I interferon (IFN) 18induction in response to VZV infection. Viral gene overexpression screening identified 19the essential VZV tegument protein ORF9 as a novel antagonist of DNA sensing via 20cGAS. Ectopically as well as virally expressed ORF9 bound to endogenous cGAS. 21Confocal microscopy revealed co-localisation of cGAS and ORF9, which blocked the 22 type I IFN response to transfected DNA. ORF9 and cGAS also interacted directly in a 23 cell-free system. Our data further suggest that ORF9 inhibited the production of 24 cGAMP by cGAS. Taken together, our work highlights the importance of the 25 cGAS/STING DNA sensing pathway for VZV recognition and identified an immune 26antagonist encoded by VZV that directly interferes with DNA sensing via cGAS. 27 28