Sedimentation analysis of the RNAs isolated from interfering particles of Lassa and Machupo viruses.

Vero cells chronically infected with Lassa virus as well as BHK-21 cells chronically infected with Machupo virus produced particles interfering with the replication of homologous, but not heterogeneous viruses. RNAs of standard virus particles contained 4 sedimentation classes of molecules: 28-31 S, 22-24S, 18 S and 4-6 S. The 28-31 S molecules were not present among the RNAs of interfering particles of Lassa and Machupo viruses.