Innate immune response in bovine neutrophils stimulated with Mycoplasma bovis

Mycoplasma bovis(M. bovis) is a significant worldwide pathogen of cattle. Neutrophils have an important role in the innate immune response during infection withM. bovis. However, even though neutrophils accumulate inM. bovisinfection, the interaction ofM. bovisand neutrophils has not been fully elucidated. We attempted to elucidate the innate immune response of neutrophils stimulated withM. bovisand evaluate the transcriptome and functional analysis of bovine neutrophils stimulated withM. bovis. Proinflammatory cytokines, such as inducible nitric oxide (iNOS), which was the most increased gene in transcriptome analysis, were increased in quantitative polymerase chain reaction analysis of bovine neutrophils stimulated with live or heat-killedM. bovis. Nitric oxide and intracellular reactive oxygen species production of neutrophils stimulated withM. boviswas significantly increased. Neutrophils stimulated withM. bovisshowed an increased ratio of nonapoptotic cell death compared to unstimulated controls. We demonstrated that neutrophil extracellular traps (NETs) formation was not recognized in neutrophils stimulated with liveM. bovis. However, heat-killedM. bovisinduced NETs formation. We also showed the interaction withM. bovisand bovine neutrophils regarding proinflammatory cytokine gene expression and functional expression related to NETs formation. Live and killedM. bovisinduced innate immune responses in neutrophils and had the potential to induce NETs formation, but liveM. bovisescaped NETs.