Oligonucleotide-poly(L-lysine)-heparin complexes: potent sequence-specific inhibitors of HIV-1 infection

Poly(L-lysine)-conjugated oligonucleotides complementary to the translation initiation region of the tat protein were tested for their capacity to inhibit HIV-1 replication in de novo infected cells. Sequence-specific antiviral effects were observed with these conjugates at 0.5 microM; their activity was transient, and the viral production was only delayed for a few days. Interestingly, their efficiency was significantly increased by the addition of heparin, a sulfated polyanion that also presents antiviral properties against HIV-1. A single addition, at the time of virus exposure, of the ternary complex formed between oligonucleotide-poly(L-lysine) (75 nM) and heparin (50 micrograms/mL) totally protects cells from HIV-1 infection. Primary interference with virus adsorption is essential for the strong antiviral effect. However, this protection remains strictly sequence specific as demonstrated in experiments performed with different HIV-1 isolates. As comparison, treatments that combine AZT and heparin at the same concentrations did not promote such a complete protection.