Inhibition of herpesvirus deoxyribonucleic acid and protein synthesis by tilorone hydrochloride.

Tilorone hydrochloride at a concentration of 10 mug/ml very efficiently inhibited herpes simplex virus growth in BSC1 cells when the virus is infected at a low multiplicity of infection. The adsorption of the virus was not affected by the drug, and the penetration of the deoxyribonucleic acid of the input virus into the cytoplasm and nuclei proceeded normally when tilorone hydrochloride was present. However, newly synthesized viral deoxyribonucleic acid was not detectable under these conditions, there was a remarkable decrease in the rate of viral polypeptide synthesis, and virus particles were not formed. The inhibition of herpesvirus growth by tilorone hydrochloride was absolutely dependent on the presence of the drug in the cultures. Pretreatment of the cells with the drug did not result in resistance to herpesvirus infection after the removal of the drug.