The interferon responsiveness of two cell lines transfected with the hepatitis B virus genome was investigated. A cosmid vector containing multiple copies of the hepatitis B virus genome was transfected into FL5-1 cells; it reduced their sensitivity to interferons as measured by inhibition of the cytopathic effect of Sindbis virus challenge. Similar vectors transfected into HeLa cells reduced their sensitivity to interferon as measured by production of β2-microglobulin.

This resistance to interferon in hepatitis B virus-transfected cells may be a trans-acting phenomenon related to nucleotide homology between hepatitis B virus DNA and sequences regulating the interferon-induced antiviral system. Alternatively, other mechanisms involving transcription or translation products of hepatitis B virus may be responsible.

Hepatitis B virus-induced cellular resistance to the action of interferon may be important in maintaining the chronic carrier state.