Antigenic relationships between an isolate of the Western Subtype of tick-borne encephalitis virus and an inactivated vaccine derived from it.

High mutation rates resulting from the error prone replicases of RNA viruses could lead to antigenic alterations in viral products and pose significant problems during the manufacture of vaccines against RNA viruses. The production of a vaccine against tick-borne encephalitis virus has been monitored using both polyclonal sera and a library of monoclonal antibodies. Only a few antigenic changes were detected during the alteration of host cell from mouse brain to avian fibroblasts and upon subsequent expansion of the virus population during several rounds of replication. In addition, when the formalin inactivation process was monitored for antigenic change, virtually none was detected.