Mycoplasma bovis induces apoptosis of bovine lymphocytes.

We report Mycoplasma bovis induces apoptotic death of bovine lymphocytes. Using flow cytometry analyzed propidium iodide inclusion we observed a loss in viable lymphocytes upon incubation of freshly isolated bovine PBMCs with M. bovis. The use of annexin V staining as well as TUNEL assays corroborated these findings. In addition, these assays indicated that the M. bovis induced lymphocyte death is apoptotic in nature. Subsequent experiments demonstrated that the prokaryotic protein production inhibitor chloramphenicol inhibited lymphocyte death induced by M. bovis, showing that M. bovis protein production is necessary for the induction of lymphocyte death, and that the death is not dependent upon the addition of apoptotic inducers as shown with other mycoplasmas. We also show that M. bovis is different from other bovine mycoplasmas (both pathogenic and non-pathogenic) with regards to this characteristic.