Inhibition of the Reverse Transcriptase Activity and Replication of Human Immunodeficiency Virus Type 1 by AS 101 In Vitro

In a search for compounds active against human immunodeficiency virus type 1 (HIV-1), it was found that the novel low-molecular weight immunoenhancer ammonium trichloro(dioxyethylene-0,0′-) tellurate (AS101) suppresses production of HIV-1 in vitro. Treatment of HIV-1-infected peripheral blood mononuclear cells (PBMC) with increasing concentrations of AS 101 resulted in substantial inhibition of virus production as measured by both reverse transcriptase (RT) activity and antigen presence in supernatants of treated cells. AS101 had no effect on PBMC viability, growth, or morphology up to a concentration of 15 μM for 14 days. To elucidate a possible mechanism for the inhibition of AS 101, we have analyzed the effect of the drug on the catalytic functions associated with HIV RT, namely the RDDP, DDDP, and RNase H activities. RDDP and DDDP activities were impaired by the drug with calculated IC₅₀ value of about 4 μM. On the other hand, the RNase H activity was less sensitive to AS101, with an apparent IC₅₀ value of about 30 μM. The anti-HIV-1 activity of AS 101 as reflected by inhibition of the different catalytic functions associated with viral RT, in the absence of drug-related toxicity to lymphocytes, together with its immunomodulating activity strongly argues in favor of its evaluation, as a therapeutic agent for patients with HIV infection.