Cell specific uptake of antiretroviral drugs: AZT coupled to LDL inhibits HIV replication in human macrophages.

Macrophages, besides helper T-lymphocytes, are target cells for the human immunodeficiency virus (HIV). We report on a mechanism to deliver selectively antiretroviral drugs to cells of the monocyte/macrophage lineage. These cells and cells of the endothelium express scavenger receptors which mediate the transport of modified low density lipoprotein (LDL). LDL modified by covalently bound azidothymidine (AZT), a potent inhibitor of HIV replication, is internalized via this pathway into human macrophages. Treatment of HIV-1 infected human macrophages with AZT-LDL showed in vitro efficient inhibition of viral replication. In contrast, HIV replication in T-lymphocytes (Molt 4/8), which do not express scavenger receptors, is not inhibited by AZT-LDL but by free AZT.