Lack of detectable circulating interferon in mice protected against vaccinia virus by induction and elicitation with bacterial systems.

Mice which had been subjected to mycobacterial infection and specific elicitation were bled from the orbital sinus at the time the mice were challenged intravenously with vaccinia virus. Assays of the sera were negative for interferon. Sera of rabbits sensitized with staphylococci and elicited by Staphage Lysate also lacked detectable circulating interferon.