The
simian acquired immunodeficiency syndrome (
SAIDS) in macaques at the Washington Regional Primate Research Center is associated with a type D retrovirus known as
SAIDS-D/WA. We tested the ability of
3'-azido-3'-deoxythymidine (AZT),
2',3'-dideoxycytidine (ddC), and
2',3'-dideoxyadenosine (
ddA) to inhibit the in vitro cytopathic effect (syncytium formation) and infectivity of the
SAIDS-D/WA virus. Raji cell cultures were infected with virus and treated with various concentrations of AZT, ddC, and
ddA. The ability of these drugs to inhibit replication of the
SAIDS-D/WA virus in Raji cells was monitored by syncytium formation, expression of
viral antigen, and
reverse transcriptase assay. At concentrations of 4, 40, and 400 microM, AZT completely blocked the viral infectivity and inhibited the cytopathic effect of
SAIDS-D/WA. Likewise, ddC was inhibitory at concentrations of 5 and 50 microM and
ddA was inhibitory at 100 and 200 microM. AZT, ddC, and
ddA became
cytostatic to Raji cells with increasing
drug concentrations. AZT also partially inhibited
SAIDS-D/WA replication in previously infected Raji cell cultures, and viral inhibition increased in response to the concentration of AZT. These data indicate that AZT, ddC, and
ddA are effective
antiretroviral agents that merit further evaluation, including clinical trials, in animal models with
AIDS-like diseases.