MRC-5 Cells, a Model for Junin Virus Persistent Infection

Abstract

SUMMARYPersistent infection of MRC-5 cells was established following inoculation with attenuated Junin virus (JV). In the acute phase of the infection both the pathogenic XJ and the attenuated X J0 and XJC13 strains showed severe c.p.e, and free viral titres reached 10 5 p.f.u./ml. Recovery and establishment of persistently infected MRC-5 sublines (MRC-5p0 proved a very common event and seemed to be independent of viral strain, m.o.i, employed or virus passage history. These MRC-5m sublines released virus throughout their life span and infectious centre assays performed at different passage levels with two sublines showed that 5 to 9 ~o of the cells were producing virus. Heterotypic but not heterologous resistance to superinfection developed, as observed in persistent JV heteroploid cell systems. Analysis of released JV showed that attenuation had not been markedly altered, but alteration in plaque morphology under methyl cellulose, appearance of temperature-sensitive mutants and alterations in mouse pathology imply that some properties of J V have been altered. Results presented here stress once again the ability of JV to establish persistent infections. The source and diploid characteristics of MRC-5 cells make them a satisfactory model for JV persistence studies.