Inactivation of human interferon by body fluids.

We have shown almost all samples of serum, saliva, cerebrospinal fluid, fecal extract, bile or urine tested contain a substance or substances capable of inactivating human interferon at normal body temperature. This adverse effect appears to be greater for fibroblast interferon-induced by either polynucleotides or viruses, than for leukocyte interferon induced by viruses. These results have a number of implications for the clinical utilization of this natural antiviral substance.