[Persistence of Japanese encephalitis virus clones in continuous HeLa cells].

Some virological and biological properties of the H-N and H-P systems (cells of HeLa line clone persistently infected with the Nakayama and Peking I strains of Japanese encephalitis virus, JE, respectively) were studied. A feature distinguishing these systems from all previously described models of persistent infection (PI) of vertebrate cells with JE virus consisted in the lack of visible signs of virus-specific degeneration of the cultures. Attempts to free PI cells from persisting viruses by changing cultivation conditions or with virus-specific antibodies failed. The "zone" phenomenon frequently observed in PI as well as resistance of the cultures to superinfection with isologous viruses only appeared to indicate the presence of interfering particles in the H-N and H-P systems.