Defective interfering particles of encephalomyocarditis virus

Encephalomyocarditis (EMC) virus and five temperature-sensitive mutants of EMC virus were serially passed numerous times in HeLa, L929 and BHK-21 cells. Equilibrium centrifugation in CsCl density gradients of virus and electrophoresis of virus RNA from many of the high number passages indicated the presence of standard EMC virus and particles containing RNA of lower molecular weight. Three virus isolates with high passage number were able to interfere with the replication of the standard virions in mixed infections. We believe our results show the generation of defective interfering particles of EMC virus.