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Cowled C.,CSIRO | Baker M.,CSIRO | Baker M.,University of New Mexico | Tachedjian M.,CSIRO | And 4 more authors.
Developmental and Comparative Immunology | Year: 2011

Bats are believed to be reservoir hosts for a number of emerging and re-emerging viruses, many of which are responsible for illness and mortality in humans, livestock and other animals. In other vertebrates, early responses to viral infection involve engagement of Toll-like receptors (TLRs), which induce changes in gene expression collectively leading to an "antiviral state" In this study we report the cloning and bioinformatic analysis of a complete set of TLRs from the black flying fox Pteropus alecto, and perform quantitative tissue expression analysis of the nucleic acid-sensing TLRs 3, 7, 8 and 9. Full-length mRNA transcripts from TLRs homologous to human TLRs 1-10 were sequenced, as well as a nearly intact TLR13 pseudogene that was spliced and polyadenylated. This prototype data can now be used to design functional studies of the bat innate immune system. © 2010. Source


Baker M.L.,CSIRO | Baker M.L.,University of New Mexico | Tachedjian M.,CSIRO | Wang L.-F.,CSIRO | Wang L.-F.,Australian Biosecurity Cooperative Research Center for Emerging Infectious Diseases
Immunogenetics | Year: 2010

Bats are the natural host reservoir for range of emerging and re-emerging viruses, many of which cause significant morbidity and mortality in other mammals, yet appear to result in no clinical consequences for bats. The ability of bats to coexist with a variety of viruses presents an interesting immunological problem that has not been examined in any detail but which could provide significant insights into the evolution of antiviral mechanisms in mammals. Towards a better understanding of the bat immune system, we analysed the expressed heavy chain variable (VH) regions of antibodies from the black flying fox, Pteropus alecto. The germline repertoire of the closely related Pteropid bat, Pteropus vampyrus, whose genome has been sequenced was also examined for comparative purposes. Representative VH genes were found in all three mammalian VH clans (I, II and III) in both the expressed P. alecto VH repertoire and the germline P. vampyrus VH repertoire. Evidence for the use of multiple heavy chain diversity (DH) and joining (JH) segments for the generation of diverse VDJ rearrangements was also present in the expressed antibody repertoire of P. alecto. The long period of co-evolutionary history of bats with viruses may have resulted in a variety of highly specific VH segments being hardwired into the genomes of bats and may have implications for their ability to successfully cope with a diversity of viral antigens. © 2010 Springer-Verlag. Source


Marsh G.A.,Australian Animal Health Laboratory | Todd S.,Australian Animal Health Laboratory | Foord A.,Australian Animal Health Laboratory | Hansson E.,Australian Animal Health Laboratory | And 9 more authors.
Emerging Infectious Diseases | Year: 2010

Bat-to-horse transmission of Hendra virus has occurred at least 14 times. Although clinical signs in horses have differed, genome sequencing has demonstrated little variation among the isolates. Our sequencing of 5 isolates from recent Hendra virus outbreaks in horses found no correlation between sequences and time or geographic location of outbreaks. Source


Papenfuss A.T.,Walter and Eliza Hall Institute of Medical Research | Papenfuss A.T.,University of Melbourne | Baker M.L.,CSIRO | Baker M.L.,University of New Mexico | And 10 more authors.
BMC Genomics | Year: 2012

Background: Bats are the natural reservoir host for a range of emerging and re-emerging viruses, including SARS-like coronaviruses, Ebola viruses, henipaviruses and Rabies viruses. However, the mechanisms responsible for the control of viral replication in bats are not understood and there is little information available on any aspect of antiviral immunity in bats. Massively parallel sequencing of the bat transcriptome provides the opportunity for rapid gene discovery. Although the genomes of one megabat and one microbat have now been sequenced to low coverage, no transcriptomic datasets have been reported from any bat species. In this study, we describe the immune transcriptome of the Australian flying fox, Pteropus alecto, providing an important resource for identification of genes involved in a range of activities including antiviral immunity.Results: Towards understanding the adaptations that have allowed bats to coexist with viruses, we have de novo assembled transcriptome sequence from immune tissues and stimulated cells from P. alecto. We identified about 18,600 genes involved in a broad range of activities with the most highly expressed genes involved in cell growth and maintenance, enzyme activity, cellular components and metabolism and energy pathways. 3.5% of the bat transcribed genes corresponded to immune genes and a total of about 500 immune genes were identified, providing an overview of both innate and adaptive immunity. A small proportion of transcripts found no match with annotated sequences in any of the public databases and may represent bat-specific transcripts.Conclusions: This study represents the first reported bat transcriptome dataset and provides a survey of expressed bat genes that complement existing bat genomic data. In addition, these data provide insight into genes relevant to the antiviral responses of bats, and form a basis for examining the roles of these molecules in immune response to viral infection. © 2012 Papenfuss et al.; licensee BioMed Central Ltd. Source


Virtue E.R.,CSIRO | Virtue E.R.,Australian Biosecurity Cooperative Research Center for Emerging Infectious Diseases | Virtue E.R.,University of Melbourne | Marsh G.A.,CSIRO | And 4 more authors.
PLoS ONE | Year: 2011

Bats are natural reservoirs for a spectrum of infectious zoonotic diseases including the recently emerged henipaviruses (Hendra and Nipah viruses). Henipaviruses have been observed both naturally and experimentally to cause serious and often fatal disease in many different mammal species, including humans. Interestingly, infection of the flying fox with henipaviruses occurs in the absence of clinical disease. The extreme variation in the disease pattern between humans and bats has led to an investigation into the effects of henipavirus infection on the innate immune response in bat cell lines. We report that henipavirus infection does not result in the induction of interferon expression, and the viruses also inhibit interferon signaling. We also confirm that the interferon production and signaling block in bat cells is not due to differing viral protein expression levels between human and bat hosts. This information, in addition to the known lack of clinical signs in bats following henipavirus infection, suggests that bats control henipavirus infection by an as yet unidentified mechanism, not via the interferon response. This is the first report of henipavirus infection in bat cells specifically investigating aspects of the innate immune system. © 2011 Virtue et al. Source

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