Anoxia induces human immunodeficiency virus expression in infected T cell lines

The effects of oxygen deprivation, or anoxia, on human immunodeficiency virus (HIV-1) expression in chronically (ACH.2) and acutely (H9/HIV-1-IIIB) infected cell lines was investigated. Temporary cellular anoxia has previously been shown to activate transcription of endogenous type C leukemia virus sequences, resulting in a significant increase in retroviral RNA within the cell (1). Here we report a 15-fold increase in HIV-1-specific RNA in unstimulated ACH.2 T cells within 24 h of anoxia. This induction of RNA is accompanied by an accumulation of intracellular p24 gag protein as well as an increase in envelope protein. Anoxia induces a further increase in total HIV-1 RNA in ACH.2 cells prestimulated to produce virus by phorbol 12-myristate 13-acetate and in H9 T cells acutely infected with HIV-1-IIIB. The induction of RNA in ACH.2 cells appears to be reversible. Anoxic culture for 24 h followed by a 24-h re-oxygenation period results in a return to "resting state" levels of HIV-1 RNA. These data indicate that oxygen tension within the cellular environment modulates HIV-1 expression, providing a model system in which to study the reversible regulation of HIV-1 RNA and viral gene products within the cell.