[Accumulation of certain arenaviruses in transplantable VERO and BHK-21 cells].

Production of Lassa and Machupo viruses in Vero and BHK-21 cells was studied in relation to various conditions of the infected cell cultivation and as a function of different multiplicities of infection. The highest titers (expressed in PFU/ml) were obtained when the cells were grown in roller bottles with daily changes of the medium. The maximum titer in Lassa virus-infected cells was over 10(6), in Machupo virus-infected cells over 10(7). The effect of the autointerfering factor on the growth of Machupo virus was demonstrated. An increase in the multiplicity of infection led to a decrease in the yield of Machupo virus. Production of Pichinde and Machupo viruses in a monocyclic growth experiment was studied. The maximum yield of cell-associated and extracellular Pichinde virus was obtained at 24-32 hours postinfection, and that of extracellular Machupo virus at 32-40 hours postinfection.