Inhibition of the Friend retrovirus by antisense oligonucleotides encapsulated in liposomes: mechanism of action.

Proliferation of the Friend retrovirus was specifically inhibited by the env mRNA complementary oligonucleotide encapsulated in pH-sensitive liposomes. This observation was made using the focus immunoassay (FIA) and the reverse transcriptase test. The key finding of the present study was the dramatic impact on liposome penetration. For chronic or de novo infection, the point at which the penetration of liposomes began corresponded to the time needed for the virus to leave the cell. In the absence of the virus, liposomes remained adsorbed onto the cell surface without any internalization. Regardless of the mechanism involved, the fact that a retroviral infection stimulates the cellular uptake of oligonucleotide liposomes widens the spectrum of strategies for specific antiviral action.