Experimental infection of ponies with equine influenza A2 (H3N8) virus strains of different pathogenicity elicits varying interferon and interleukin-6 responses.
The production of interferon (IFN), interleukin-6 (IL-6), and tumor necrosis factor (TNF) was monitored in horses during the course of influenza A2 virus infections. The effects of two virus strains, Newmarket/2/93 and Sussex/89, were compared, of which the latter is considered the more pathogenic in terms of clinical signs. Ten naive ponies were infected with influenza A/equine/Sussex/89 and 10 with influenza A/equine/Newmarket/2/93, respectively. As expected ponies infected with Sussex/89 showed the most pronounced clinical signs but there was no notable difference in viral excretion compared with Newmarket/2/93. IFN was detected in nasal secretions of all ponies infected with Sussex/89 but only in 2 ponies infected with Newmarktet/2/93. IFN was not detected in serum of any animal. IL-6 activity was detected in nasal secretions of all experimental animals from day 2 and onwards, but showed markedly higher IL-6 responses were observed in ponies infected with Sussex/89. No TNF activity was detected in any of the samples collected. In summary, equine influenza A 2 infections elicited local, and in some cases systemic, IFN and IL-6 responses in the ponies. Interestingly, there was some evidence that the duration and levels of cytokine responses may be related to the pathogenicity of the influenza strains.
Wattrang
Eva
E
Unit of Comparative Medicine and Physiology, Department of Large Animal Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden. Eva.Wattrang@kirmed.slu.se
Jessett
David M
DM
Yates
Phillip
P
Fuxler
Lisbeth
L
Hannant
Duncan
D
D000818:Animals; D002417:Cattle; D002460:Cell Line; D005260:Female; D006734:Horse Diseases / Q000276:immunology* / Q000821:virology; D006736:Horses; D053123:Influenza A Virus, H3N8 Subtype; D009980:Influenza A virus / Q000145:classification / Q000276:immunology / Q000472:pathogenicity*; D007372:Interferons / Q000096:biosynthesis*; D015850:Interleukin-6 / Q000096:biosynthesis*; D008297:Male; D051379:Mice; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000662:veterinary*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D007372:Interferons