Histophilus somni Stimulates Expression of Antiviral Proteins and Inhibits BRSV Replication in Bovine Respiratory Epithelial CellsReportar como inadecuado




Histophilus somni Stimulates Expression of Antiviral Proteins and Inhibits BRSV Replication in Bovine Respiratory Epithelial Cells - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Our previous studies showed that bovine respiratory syncytial virus BRSV followed by Histophilus somni causes more severe bovine respiratory disease and a more permeable alveolar barrier in vitro than either agent alone. However, microarray analysis revealed the treatment of bovine alveolar type 2 BAT2 epithelial cells with H. somni concentrated culture supernatant CCS stimulated up-regulation of four antiviral protein genes as compared with BRSV infection or dual treatment. This suggested that inhibition of viral infection, rather than synergy, may occur if the bacterial infection occurred before the viral infection. Viperin or radical S-adenosyl methionine domain containing 2—RSAD2 and ISG15 IFN-stimulated gene 15—ubiquitin-like modifier were most up-regulated. CCS dose and time course for up-regulation of viperin protein levels were determined in treated bovine turbinate BT upper respiratory cells and BAT2 lower respiratory cells by Western blotting. Treatment of BAT2 cells with H. somni culture supernatant before BRSV infection dramatically reduced viral replication as determined by qRT PCR, supporting the hypothesis that the bacterial infection may inhibit viral infection. Studies of the role of the two known H. somni cytotoxins showed that viperin protein expression was induced by endotoxin lipooligosaccharide but not by IbpA, which mediates alveolar permeability and H. somni invasion. A naturally occurring IbpA negative asymptomatic carrier strain of H. somni 129Pt does not cause BAT2 cell retraction or permeability of alveolar cell monolayers, so lacks virulence in vitro. To investigate initial steps of pathogenesis, we showed that strain 129Pt attached to BT cells and induced a strong viperin response in vitro. Thus colonization of the bovine upper respiratory tract with an asymptomatic carrier strain lacking virulence may decrease viral infection and the subsequent enhancement of bacterial respiratory infection in vivo.



Autor: C. Lin, J. T. Agnes, N. Behrens, M. Shao †, Y. Tagawa, L. J. Gershwin, L. B. Corbeil

Fuente: http://plos.srce.hr/



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