Pigs were inoculated intratracheally with 106.0 mean egg infectious dose (EID50) A/Swine/Belgium/1/98 (H1N1) virus. At the time of challenge and 18 h later, they were injected intratracheally and intraperitoneally with a high dose of IFN-α neutralizing Abs or control Abs. The animals were euthanized at 0, 24, 30, 48 and 72 h after inoculation.
At 24 and 30 h, IFN-α levels in broncho-alveolar lavage fluid of K9 recipient animals were strongly suppressed, and this coincided with reduced IL-6 and IL-12 levels. TNF-α and IL-1 levels were unaffected compared to those in the control Ab treated group. Importantly, the onset and peak of clinical symptoms in IFN-α neutralizing Abs treated animals were delayed by 24 h, simultaneously with the suppression of IFN-α, but there was no obvious effect on virus replication and lung pathology. These results suggest an important role for IFN-α in IL-6 and IL-12 induction and a role of all three cytokines in the symptoms of swine influenza.
F. Barbé, X. Saelens, D. Braeckmans, F. Lefèvre and K. Van Reeth. Role of IFN-α during the acute stage of a swine influenza virus infection. Research in Veterinary Science. 2010. Vol. 88 (1): 172-178.