Marked induction of IL-6, haptoglobin and IFNgamma following experimental BRSV infection in young calves.
Bovine respiratory syncytial virus (BRSV) has been identified worldwide as an important pathogen associated with acute respiratory disease in calves. An infection model has been developed reflecting accurately the clinical course and the development of pathological signs during a natural BRSV-infection. In the experiments described in the present study, calves were infected at 13-21 weeks of age and reinfected 14 weeks later. Blood samples from the entire infection period were analysed for acute phase protein (haptoglobin) by ELISA and for expression (mRNA level in peripheral blood mononuclear cells) of the cytokines interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6) and interferon-gamma (IFNgamma) by quantitative real-time reverse transcribed polymerase chain reaction (RT-PCR). IFNgamma, interleukin-6 and haptoglobin were markedly induced together with development of clinical signs in response to the first infection with BRSV. The IFNgamma response was biphasic, with an early peak at day 1-3 post infection (p.i.) and a later increase between day 5 and 8 p.i. Reinfection also resulted in an induction of IFNgamma, but without induction of clinical signs, IL-6 and haptoglobin. These results indicate that early mediators connected with the innate responses are induced on a first encounter with the pathogen, but not on a second encounter (reinfection) where the adaptive immune system may act as the first line defence.
Grell
Susanne Nedergaard
SN
Department of Immunology Biochemistry, Danish Institute for Food and Veterinary Research, Copenhagen, Denmark. sng@dfvf.dk
Tjørnehøj
Kirsten
K
Larsen
Lars Erik
LE
Heegaard
Peter Mikael Helweg
PM
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001831:Body Temperature; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D006242:Haptoglobins / Q000096:biosynthesis* / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000097:blood; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000097:blood; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D018112:Respiratory Syncytial Virus, Bovine / Q000276:immunology*; D012140:Respiratory Tract Diseases / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
D000914:Antibodies, Viral; D006242:Haptoglobins; D015850:Interleukin-6; D012333:RNA, Messenger; D007371:Interferon-gamma