Paramyxovirus-avian cell relationship: discrepant impact of 6-azauridine on virus production by susceptible and less susceptible cells.

The replication of mumps virus in susceptible chicken embryonic heart cells was escalated by daily treatment of cultures with 6-azauridine (6-AU). On the other hand, virus production by less susceptible liver cells was depressed by 6-AU. The population of infected susceptible cells was not increased, but the release of virus by infected susceptible cells was enhanced 20-fold by 10 mug of 6-AU per ml. Less susceptible cells, which incorporated less ribonucleic acid and protein precursor than susceptible cells, sustained a constant level of viral release during 6-AU treatment; however, the number of infected less susceptible cells underwent substantial decline.