Attempts to standardize the screening for antiviral drugs by in vitro tests.

Plaque reduction (PR) and persistent infection cell culture (PICC) tests were used as a standard procedure for the selection of effective and well-tolerated antiviral compounds. Antiviral activity and cytotoxicity as well as other characteristics of the test compound, i.e., the development of drug resistance or the potential for activating the multiplication of other viruses can be examined by this method. In the described system analogues of 2'-deoxyuridine were tested against herpes simplex virus.