Bovine seminal RNase induces apoptosis in normal proliferating lymphocytes.

Bovine seminal ribonuclease is a member of the RISBAses (ribonucleases with special biological actions) family. It exerts specific anti-tumor, embryotoxic, aspermatogenic and immunosuppressive activities. The cytotoxic effect of bovine seminal ribonuclease on tumor cells is accompanied by the induction of apoptosis. We provide ultrastructural and flow cytometry evidence of apoptotic death following bovine seminal ribonuclease treatment, in normal cells and phytohemagglutinin-stimulated lymphocytes. Transmission and scanning electron microscopy, which were fully supported by flow cytometry data, showed typical features of apoptosis, such as decreased cell size, chromatin condensation, fragmentation in micronuclei, and the presence of apoptotic bodies.