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, embryot oxic, aspermatogenic and immunosuppressive activities. The cytotoxic effect of bovine seminal ribonuclease on tumor cells is accompanied by the induct ion 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 scan ning electron microscopy, which were fully supported by flow cytometry data , showed typical features of apoptosis, such as decreased cell size, chroma tin condensation, fragmentation in micronuclei, and the presence of apoptot ic bodies.