Lysosomal changes in lytic and nonlytic infections with the simian vacuolating virus (SV40).

Lysosomal changes have been observed by histochemical methods in the BSC-1 green monkey kidney cell line and the 3T3 mouse cell line infected with high multiplicities of simian vacuolating virus (SV40) and in 3T3 cells infected with herpes simplex virus. BSC-1 cells infected with SV40 showed marked cytoplasmic vacuolation and lysis. The lysosomes were enlarged and aggregated and there was second-stage activation with release of enzyme into the cytoplasm. Possibly, some product of viral replication in the nucleus is released into the cytoplasm and brings about changes in lysosomes and other cytoplasmic organelles. Lysosomal enzymes probably contribute to the dissolution of cells and release of virus from nuclei. 3T3 cells infected with SV40 under these conditions do not lyse, but a large proportion may become transformed. First-stage activation of lysosomes was seen for at least 6 days. After 6 days these changes disappeared. The possible relationship of lysosomal changes to the events occurring in transformed cells is discussed. The cells infected with herpes simplex virus showed marked cytopathic effects associated with second-stage lysosomal activation.