CELL-CYCLE ARREST BY VPR IN HIV-1 VIRIONS AND INSENSITIVITY TO ANTIRETROVIRAL AGENTS

Expression of human immunodeficiency virus-type 1 (HIV-1) Vpr after pr oductive infection of T cells induces cell cycle arrest in the G(2) ph ase of the cell cycle. In the absence of de novo expression, HIV-1 Vpr packaged into virions still induced cell cycle arrest. Naturally noni nfectious virus or virus rendered defective for infection by reverse t ranscriptase or protease inhibitors were capable of inducing Vpr-media ted cell cycle arrest. These results suggest a model whereby both infe ctious and noninfectious virions in vivo, such as those surrounding fo llicular dendritic cells, participate in immune suppression.