Hi, this line itself doesn't necessarily mean the Plesk Antivirus will be enabled (this line remained from time when it was licensed differently). Plesk Antivirus has its own license shipped as so-called Additional Key. However in most cases this line and Plesk Antivirus would be enabled together. You can either try Plesk Antivirus and see (1), or contact your sales representative (2) or in case you purchased from Parallels directly, drop your key ID as a private message to me and I will check it for you (3).
Regards