Direct and Cell-Mediated Effects of Interferon-α and -γ on Cells Chronically Infected with HTLV-III

The replication of the human T lymphotropic retrovirus HTLV-III in persistently infected cells is relatively insensitive to the direct antiviral action of human interferon-α or -γ (IFN-α or -γ), showing only a two- to threefold reduction of HTLV-III, even though the host cells are very sensitive to IFN, as shown by vesicular stomatitis virus (VSV)-yield reduction assay (4-5 log reduction of VSV). However, IFN anticellular activity is strongly enhanced in the presence of normal peripheral blood mononuclear cells, suggesting a cell-mediated effect of IFNs.