[Persistence of lymphocytic choriomeningitis virus in a transplantable line of Detroit-6 cells].

Defective LCM virus was found to persist in Detroit-6 cells. The persisting virus was not infectious for susceptible mice and some cell cultures. Its antigenic properties were enhanced to detectable levels in the CFT by cocultivation with LSV5 cells only. No reversion to its pathogenic properties, however, occurred either after 8 subpassages of the cocultivated cells or after blind passages of these cells in suckling mouse brains. The cytogenetic analysis, and the pattern of antigen fluorescence (IIF) revealed similarities between HeLa and D-6 cell lines persistently infected with LCM virus. The highest intensity of LCM virus antigen coincided with the period of maximum miotic activity of D-6-LCM cells, indicating a correlation between synthesis processes in the cells and reproduction of the persisting virus. Upon superinfection of D-6-LCM cells with homo- and isologous viruses no increase in the percentage of the antigen-containing cells was observed. No detectable interferon was found in the D-6-6CM system.