Characteristics of the antiviral effect of 9-(S)-(2, 3-dihydroxypropyl)adenine

9(S)-(2,3-Dihydroxypropyl)adenine (DHPA) at 1--3 mg/ml completely inhibited the replication of vaccinia virus in ZP cells; the analogue did not inactivate the virus. Formation of a virus component sensitive to DHPA preceded by 2 hr the formation of infectious vaccinia virus. It seems likely that the component inhibited by DHPA is viral mRNA. The virus inhibitory effect was not reverted by numerous nucleotides, nucleosides or amino acids. DHPA was not metabolized during the latent period of vaccinia virus replication cycle either in uninfected ZP or chick embryo cell cultures.