Ribonuclease activity of preparations of human lymphoblastoid interferon

Crude human lymphoblastoid interferon has less ribonuclease activity than equivalent primary leukocyte interferon and ribonuclease was eliminated when it was purified. The methods used differed from those that had failed to eliminate similar activity from leukocyte interferon. This result makes it unlikely that exogenous ribonuclease plays a major role in the antiviral action of interferon preparations.