Effect of interferon on chronic infection of human cells by xenotropic type-C viruses

Different preparations of human interferon inhibit virus production in human cells chronically infected by a variety of type-C xenotropic viruses. Some of these viruses have been incriminated in the development of leukemia in primates. The characteristics of blocking of viral multiplication are similar to those described for the effect of mouse interferon on ecotropic viruses. The amount of free virus in culture supernatants is strongly decreased while intracellular protein p30 stays unchanged or is slightly increased. On the other hand, the inhibitory effect is reversible. The withdrawal of interferon results in a rapid increase in virus production as detectable in supernatant fluids. In the light of these results it is suggested that human interferon might be useful in the treatment of some blood malignancies suspected of being related to infection with xenotropic type-C viruses.