Mechanism of interferon action: inhibition of vesicular stomatitis virus replication in human amnion U cells by cloned human gamma-interferon. I. Effect on early and late stages of the viral multiplication cycle.

N Ulker,C E Samuel

doi:10.1016/s0021-9258(18)89266-3

Abstract

The molecular basis of the inhibition of vesicular stomatitis virus (VSV) replication by pure recombinant gamma-interferon (IFN-gamma) in human amnion U cells was examined. A saturating concentration of IFN-gamma induced, at maximum, about a two log10 reduction in infectious VSV yield. The kinetics of induction of the antiviral activity by IFN-gamma were first order over the period of about 6-18 h, following a lag of about 3 h, after treatment with a saturating concentration of IFN-gamma. The relationship of the inhibition in VSV infectivity to the early and late events of the VSV multiplication cycle was investigated. IFN-gamma treatment had no detectable effect on the adsorption and penetration of VSV virions or on their uncoating to yield viral nucleocapsids. The polypeptides of adsorbed or uncoated VSV particles were neither preferentially degraded nor detectably altered in IFN-gamma-treated U cells, as compared to untreated U cells. Progeny virions isolated from IFN-gamma-treated U cells, although greatly reduced in number, were found to be equally as infectious as those isolated from untreated U cells. Progeny virions from IFN-gamma-treated cells also possessed the same composition of viral proteins as was observed for virions from untreated cells. These results suggest that conditions of IFN-gamma treatment sufficient to reduce the yield of infectious VSV progeny 100-fold do not detectably affect either the early or the late stages of the VSV multiplication cycle.

Highlights

From the Section of Biochemistry and Molecular Biology, Department of Biological Sciences, University of California, Santa Barbara, California 93106
We report the effect of IFN-y on the early and the late steps of VSV multiplication; in the following paper (14); the effect of IFN-7 on VSV macromolecular synthesis isexamined
We have examined indetail the molecular basis of the

Summary

EFFECT ON EARLY AND LATE STAGES OF THE VIRAL MULTIPLICATION CYCLE*

The molecular basis of the inhibition of vesicular (4, 5) It has recently become possible, by molecular cloning stomatitisvirus (VSV) replication by pure recombinaanntd expression, to obtain pure samples of single species of y-interferon (IFN-y) inhumana-nionU cells was human IFN proteins absolutely free of any other eukaryotic examined. A wide range of different RNA and DNA animal viruses Using recombinant human IFN-7, we have undertaken a are sensitive to theantiviral actions of type I (a,/3) and type systematic biochemical study of the effect of IFN-7 treatment. The replication of vesicular of human amnion U cells on each stage of the multiplication stomatitis virus is acutely sensitive to IFN’ in almost every kind of animal cell which responds to thisclass of regulatory proteins (1). Available evidence suggests that there is only one human IFN-y mRNA and gene

DISCUSSION

EXPERIMENTAL PROCEDURES

T h er esultin gv i r u s - c e l l

RESULTS