Cells from newborn rat brain established in primary tissue culture will support rubella virus replication

We have initiated an in vitro study comparing the susceptibility of newborn and adult animals to rubella virus (RV) associated encephalitis. Glial cells from injured adult rat brain (RG cells) have been established in continuous culture and these cells were reported to restrict RV replication. When RG cells were infected, no infectious progeny virus particles were detected in tissue culture media and only five intracellular viral polypeptides could be detected using immune precipitation techniques (p75, p60, VP44, VP41, and VP19). Two polypeptides normally associated with a productive infection. VP24 and p30, could not be detected. In this report we have applied these techniques to an investigation of RV replication in newborn brain cells and have shown that relatively normal yields of all seven polypeptides found in RV-infected cells could be detected. These data indicate that some glia from newborn brain in primary culture are permissive for RV replication unlike the restricting RG cells and that this difference in restriction is critical in determining the outcome of their infection by RV.