Simian foamy virus type 1 (SFV-1) induces apoptosis.

Foamy virus infection causes cytopathology in several cell types from different species. The mechanism of cell killing by foamy viruses is not known. In this report, the mechanism of cell death induced by simian foamy virus type 1 (SFV-1) infection was investigated in fibroblast and lymphoid derived cells lines. Infected L-929 (fibroblast) and Raji (B cell) cells showed chromatin condensation, chromatin cleavage into nucleosome oligomers, and ultrastructural changes consistent with apoptosis. These data suggest that SFV-1 induced apoptotic cell death in different cell lines from different species. The degree of apoptotic cell death in both L-929 and Raji cell lines correlated with increased virus replication. Apoptosis, therefore, is one mechanism by which SFV-1 causes cell death.