Effect of phosphonoacetate on Marek's disease virus replication.

Phosphonoacetate (PA), but not any of its analogues tested, effectively inhibited avian herpesvirus replication and viral DNA synthesis in cell cultures. At 100 mug/ml culture medium, PA completely inhibited the replication of Marek's disease virus (MDV), herpesvirus of turkeys, and owl herpesvirus, but had no measurable effect on normal cell growth. PA also inhibited DNA polymerases induced by these avian viruses. Enzyme inhibition was 50% at a PA concentration of 0.2 mug/ml. At a concentration of 3-6 mug/ml, the compound also effected a 50% inhibition of alpha (maxi) enzyme of the host DNA polymerase. It had no effect on the host beta (mini) enzyme. When administered to chickens, PA did not inhibit the replication of MDV, nor did it prevent the development of lymphoma.