Lethal mutagenesis of HIV with mutagenic nucleoside analogs

The human immunodeficiency virus (HIV) replicates its genome and mutates at exceptionally high rates. As a result, the virus is able to evade immunolo gical and chemical antiviral agents. We tested the hypothesis that a furthe r increase in the mutation rate by promutagenic nucleoside analogs would ab olish viral replication. We evaluated deoxynucleoside analogs for lack of t oxicity to human cells, incorporation by HIV reverse transcriptase, resista nce to repair when incorporated into the DNA strand of an RNA.DNB hybrid, a nd mispairing at high frequency. Among the candidates tested, 5-hydroxydeox ycytidine (5-OH-dC) fulfilled these criteria. In seven of nine experiments, the presence of this analog resulted in the loss of viral replicative pote ntial after 9-24 sequential passages of HIV in human CEM cells, In contrast , loss of viral replication was not observed in 28 control cultures passage d in the absence of the nucleoside analog, nor with other analogs tested. S equence analysis of a portion of the HIV reverse transcriptase gene demonst rated a disproportionate increase in G --> A substitutions, mutations predi cted to result from misincorporation of 5-OH-dC into the cDNA during revers e transcription. Thus, "lethal mutagenesis" driven by the class of deoxynuc leoside analogs represented by 5-OH-dC could provide a new approach to trea ting HIV infections and, potentially, other viral infections.