Mycoplasma infection can sensitize host cells to apoptosis through contribution of apoptotic-like endonuclease(s)

Mycoplasma infection may lead to various pathologies in a broad range of ho sts. It has been shown that Mycoplasma may trigger cell death in cell cultu res; however, the mechanism remains unknown. In the present paper we show t hat Mycoplasma infection of different lymphocyte and epithelial tumour cell lines leads to the inhibition of proliferation, and increased cell death, accompanied by DNA fragmentation and the morphological features of apoptosi s. We also showed that this infection leads to an increased sensitivity of cells to various inducers of apoptosis targeting different signalling pathw ays. Finally, we show that increased apoptosis is associated with overexpre ssion of an endonuclease produced by Mycoplasma. This endonuclease is recov ered in the nuclear fraction of host cells, introduces mostly DSB and is ac tive at neutral pH in the presence of divalent cations. Activation of this endonuclease is connected with limited proteolysis, which may be reproduced in vitro by snake venom serine proteinase.