Swine Interferon I. Induction in Porcine Cell Cultures with Viral and Synthetic Inducers

The production of interferon by porcine kidney (PK₁₅) cell culture in response to viral and synthetic inducers was studied. The inducers used included a synthetic double-stranded polyribonucleotide, polyriboinosinic-polyribocytidylic acid (Poly I:C), swine influenza virus and three strains of pseudorabies virus. Following exposure to these inducers cell culture fluids were examined for interferon by the plaque-reduction method.

The Poly I:C and the swine influenza virus induced production of interferon by PK₁₅ cell cultures, whereas, all three strains of pseudorabies virus at the two concentrations tested failed to induce production of interferon in vitro.

The antiviral substance produced in PK₁₅ cells was identified as an interferon because it was pH stable, non-dialyzable, sensitive to trypsin, non-sedimentable, relatively heat stable, host-species specific and it possessed broad-spectrum antiviral activity. The latter was demonstrated by inhibition of vesicular stomatitis, vaccinia and pseudorabies viruses. Differences in interferon activity against the different viruses were observed.