Combined inhibition of vaccinia virus multiplication by inhibitors of DNA synthesis.

Nine purine or pyrimidine analogues or other inhibitors of DNA synthesis were studied for their inhibition of vaccinia virus multiplication by a plaque inhibition test with a fluid overlay in Vero cell cultures, either as single substances or in combination. Experiments on combined inhibition were made with substance concentrations leading to 80-90% plaque inhibition; indifference, additive, or synergistic interaction were evaluated from normalized plaque counts. 12 substance pairs acted in a synergistic manner and 22 showed indifference. A comparison was made with the results of other DNA viruses (adenovirus, herpes simplex virus).