Resistance of hepatitis delta virus replication to interferon-alpha treatment in transfected human cells.

Interferon-alpha (IFN-alpha) is known to inhibit both DNA and RNA viruses, including hepatitis B virus (HBV). In humans the antiviral effect, if any, of IFN-alpha on hepatitis delta virus (HDV) is complicated by the fact that HDV is spread only to patients already infected with HBV. An in vitro model system was used to assay for an antiviral effect of IFN-alpha on HDV genome replication. Hep G2 cells were transfected with a plasmid containing a trimer of HDV and treated with IFN (20 or 100 units/mL) starting 1-7 days after transfection. RNA extracted from treated and nontreated cells was assayed by both slot blot and Northern analyses. The IFN-alpha treatment as expected increased the 2'-5' oligo A synthetase RNA activity, but it did not affect HDV genome replication. Thus, in the absence of HBV, it appears that HDV is resistant to IFN-alpha.