Autointerference of Marituba Virus (Bunyaviridae) in mouse L cells by defective interfering particles

The growth characteristics of Marituba virus, a member of the Bunyaviridae family, were studied in L-A9 cells. Virus yield was strictly dependent on the MOI. Quantitation of infectious virus released from the cells revealed a decrease in magnitude with continued serial passage. Specificity of the Marituba virus inhibitory response was investigated in relation to interference within homologous and heterologous viral classes. Virus particles were studied by isopycnic centrifugation in sucrose gradients. Under conditions of multiple viral passages at high multiplicity, two major classes of virus particles were produced, one band at 1.19 g/ml and another at 1.16 g/ml. Particles at 1.16 g/ml were noninfectious. Our results suggest that during the replication of Marituba virus at high MOI a population of defective interfering particles is generated.