Swine interferon. II. Induction in pigs with viral and synthetic inducers

The production of interferon by pigs in response to viral and synthetic inducers was studied. The inducers used included polyriboinosinic-polyribocytidylic acid (Poly I:C), swine influenza virus and pseudorabies virus. Following intravenous inoculation of pigs with the inducers, sera were examined for interferon by the plaque-reduction method in porcine kidney (PK(15)) cell cultures using vesicular stomatitis virus as the challenge inoculum. It was shown that pigs can produce interferon in response to each of these inducers. The pseudorabies virus used in this investigation was found to be a better interferon inducer than the swine influenza virus. The interferon produced in pigs was identified as an interferon because it was pH stable, non-dialyzable, sensitive to trypsin, non-sedimentable and possessed broad-spectrum antiviral activity as well as host-species specificity.