Enhancement of human immunodeficiency virus 1 replication in monocytes by 1,25-dihydroxycholecalciferol.

Human immunodeficiency virus (HIV) expression and replication are under tight regulatory control. We demonstrate that 1,25-dihydroxycholecalciferol 1,25-(OH)2D3 enhances the replication of monocyte- and lymphocyte-tropic strains of HIV-1 up to 10,000-fold in monocyte cell lines, peripheral blood monocytes, and unfractionated peripheral blood mononuclear cells. 1,25(OH)2D3 is therefore one of the most potent regulators of HIV-1 replication described to date. Precursors of 1,25(OH)2D3 enhance HIV-1 replication in proportion to their affinity for the 1,25(OH)2D3 intracellular receptor, suggesting that 1,25(OH)2D3 influences HIV-1 replication by mechanisms involving this receptor. These studies may have important implications for the design of effective therapy of HIV-1 infection.