Failure of azidothymidine to inhibit human immunodeficiency virus (HIV) replication in a promonocytic cell line (U937).

The inhibitory effect of azidothymidine (AZT) on HIV replication in the promonocytic cell line U937 was investigated. After infection with HIV-1/LAV virus, U937 cells were cultured for prolonged period in the presence of the drug at a final concentrations of 20 mumol/l or 50 mumol/l, respectively. The antiviral activity was determined according to the inhibition of viral reverse transcriptase activity, and of viral antigen production (immunofluorescence assay). We conclude that virus production was not efficiently influenced during long term passage even at high drug concentrations.