Regulatory B cells control dendritic cell functions

IL-10-producing B cells are a new family of regulatory cells that control the immune responses at the innate and adaptive levels. In the neonatal context, we described that such regulatory B cells (Bregs) dampened immune responses to adjuvants and vaccines. For a long time, it has been postulated that immune system immaturity was responsible for this phenomenon; however, increasing evidence indicates that immune regulation rather than immaturity is at work. We demonstrated that innate CD5(+) Bregs negatively control innate inflammation and dendritic cell functions in neonatal mice by producing high amounts of IL-10 following Toll-like receptor triggering. These immune regulatory mechanisms can protect from lethal inflammation, control the development of autoimmune diseases, such as experimental autoimmune encephalomyelitis, and could be evoked in chronic inflammatory states, such as in cancer.