Comparative analysis of innate immune responses following infection of newborn calves with bovine rotavirus and bovine coronavirus.
Bovine rotavirus (BRV) and bovine coronavirus (BCV) are important causes of diarrhoea and death in newborn calves. Although these viruses belong to distinct viral classes, they both infect intestinal epithelial cells and induce similar clinical symptoms. Rotavirus usually causes an acute infection, but coronavirus infection can persist and reoccur in adults. Differences in viral structure and clinical outcome prompted us to postulate that innate mucosal immune responses would be markedly different following rotavirus and coronavirus infections. To address this hypothesis, gene expression following BRV and BCV infection was analysed in surgically prepared intestinal loops from 1-day-old colostrum-deprived calves. Gene expression was profiled at 18 h post-infection using bovine cDNA microarrays; the majority of differentially expressed significant genes were associated with the cell cycle and innate immune responses. A select group of these genes was validated by quantitative real-time PCR (qRT-PCR). The expression of genes associated with interferons (IFNs), cytokines and Toll-like receptors, which were not present on the microarray, was analysed further by qRT-PCR. Strong activation of TLR3, IL-6 and p65 was observed in BRV-infected host tissues, but not in tissues infected with BCV. Both viruses also downregulated IFN- and pro-inflammatory cytokine-associated pathways. In vitro studies confirmed that IFN inhibited viral replication. All of these results together suggested either that very early events of host responses at 18 h post-infection were being observed, or that both viruses have unique effective strategies to evade host immune responses.
Aich
Palok
P
Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada.
Wilson
Heather L
HL
Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada.
Kaushik
Radhey S
RS
Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada.
Potter
Andy A
AA
Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada.
Babiuk
Lorne A
LA
Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada.
Griebel
Philip
P
Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada.
D000818:Animals; D000831:Animals, Newborn; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000821:virology; D018352:Coronavirus Infections / Q000276:immunology* / Q000473:pathology / Q000662:veterinary; D017938:Coronavirus, Bovine; D003967:Diarrhea / Q000662:veterinary / Q000821:virology; D005260:Female; D007113:Immunity, Innate / Q000276:immunology*; D007583:Jejunum / Q000166:cytology / Q000473:pathology / Q000821:virology; D012400:Rotavirus Infections / Q000276:immunology* / Q000473:pathology / Q000662:veterinary