[Persistent infection of pig embryo kidney cell cultures caused by a variant of tick-borne encephalitis virus].

The results of modelling and study of persistent infection of pig embryo kidney cell cultures (PEK) with MF variant of tick-borne encephalitis (TBE) virus are presented. In the life of chronically infected cultures periods of formation and stabilization were observed which were characterized by different types of relationships between the persisting virus and the cells. By the characters under study the persisting virus did not differ significantly from the initial MF variant. Inoculation of PEK and BHK-21 cell monolayers with samples of DNA from chronically infected cultures permitted to isolate transfected agents. Their identification by the neutralization tests and the indirect immunofluorescence procedure confirmed that they belonged to TBE virus. It is suggested that the mechanism of TBE virus persistence in PEK-MF system is based on the integration of TBE virus genome with DNA of chronically infected PEK cells.