Inhibition of cellular alpha and virally induced deoxyribonucleic acid polymerases by the triphosphate of acyclovir.

The effect of the triphosphate of 9-(2-hydroxyethoxymethyl)guanine (acyclovir, acycloguanosine) on cellular alpha deoxyribonucleic acid (DNA) polymerases (DNA nucleotidyltransferases), DNA polymerases of several members of the herpes group, vaccinia virus DNA polymerase, and Friend leukemia virus ribonucleic acid-dependent DNA polymerase was examined. Several viruses, which were found to be susceptible to acyclovir, were found to induce DNA polymerases which were sensitive to acyclovir triphosphate (acyclo-GTP). Human cytomegalovirus and the H29R strain of herpes simplex virus type 1, however, were found to be relatively insusceptible to acyclovir, even though their induced DNA polymerases were inhibited by low concentrations of acyclo-GTP. The amount of acyclovir anabolized to acyclo-GTP was significantly lower for human cytomegalovirus and H29R than for the more susceptible viruses. Vaccinia virus and Friend leukemia virus induced DNA polymerases which were insensitive to inhibition by low concentrations of acyclo-GTP, anabolized little acyclovir to acyclo-GTP, and were found to be insensitive to inhibition by acyclovir. Uninfected WI-38 cells were not susceptible to inhibition by acyclovir, anabolized little acyclovir to acyclo-GTP, and had an alpha DNA polymerase which was insensitive to inhibition by low concentrations of acyclo-GTP.