Kinetics of regulatory dendritic cells in inflammatory responses during Trypanosoma evansi infection.

Trypanosoma evansi (T. evansi) causes a wasting disease in almost all mammals. Trypanosoma evansi infection gives rise to the inflammatory responses that contribute to the development of inflammation-associated tissue injury. To determine what kinds of inflammatory molecules play roles in the pathogenicity of T. evansi infection, polymerase chain reaction array analysis was performed on samples from the infected and uninfected mice. The inflammatory cytokine and chemokine storm, caused mainly by macrophages, was observed. On the other hand, the expression levels of Ccl8 and Il10 in splenocytes were also markedly increased. These results suggested an augmentation in the number and activity of regulatory dendritic cells (DCs). Therefore, the kinetics of regulatory DCs in T. evansi-infected mice were investigated. During T. evansi infection, the regulatory DCs became prevalent, with reducing the amount of inflammatory DCs. Interestingly, when the regulatory DCs were implanted into T. evansi-infected mice, the survival was prolonged, and the expression levels of inflammatory molecules were suppressed. Taken together, these results showed that a subset of regulatory DCs acted as a potential regulator of the inflammatory responses.