Biological and macromolecular properties of murine cells persistently infected with MHV-JHM

Leibowitz, J. L.; Bond, C. W.; Anderson, K.; Goss, Susan

A persistently-infected neuroblastoma culture [Neuro-2A (JHMV)] was established with the murine hepatitis virus JHM [MHV-JHM]. After 100 days of passage, the endogenous virus [Neuro-2A (JHMV) end] released by this culture was unable to induce the syncytia typical of MHV-JHM and the endogenous virus was not temperature-sensitive. The Neuro-2A (JHMV) culture was cured of virus production by passage under neutralizing antibody [Neuro-2A (JHMV) Ab]. The Neuro-2A (JHMV) and the Neuro-2A (JHMV) Ab cultures were as susceptible to heterologous infection with mengovirus and vesicular stomatitis virus as the uninfected Neuro-2A culture. However, the Neuro-2A (JHMV) and Neuro-2A (JHMV) Ab cultures were partially resistant to homologous superinfection by MHV-JHM and the closely related MHV-A59. Virus related to MHV-JHM was rescued from the antibody-cured cells by cell fusion. The synthesis of MHV-JHM specific antigens by Neuro-2A (JHMV) cells, Neuro-2A (JHMV) Ab cells and 17 Cl-1 cells infected by Neuro-2A (JHMV) end was studied by SDS-PAGE. The genomic RNAs of MHV-JHM and Neuro-2A (JHMV) end were compared by oligonucleotide mapping. The results of the protein and RNA studies indicated that the genome of Neuro-2A (JHMV) end was substantially modified from the genome of MHV-JHM, but the modifications did not significantly alter the molecular size of the viral-specific proteins.