Study revealed the important role of regulatory B cells in control of malaria-induced immunopathology

Cerebral malaria (CM) is a neurological syndrome often occurring in human severe malaria. Although CM is known as an immunopathology in brain tissue mediated by excessive pro-inflammatory cytokines, the immunoregulatory mechanism is poorly understood. Dr. Su’s research group investigated the role of IL-10-producing regulatory B cells (Breg) in modulation of CM development in murine malaria model. They found that blood-stage malaria infection in mice induced expansion of the IL-10-producing Bregs. Adoptive transfer of the Bregs to malaria-infected mice significantly reduced the accumulation of cytotoxic cells and hemorrhage in brain tissue, and improved the survival of the mice compared with control groups. Treatment of Breg recipient mice with anti-IL-10 receptor mAb blocked the protective effect of Bregs. Adoptive transfer of CD4⁺CD25⁺ regulatory T cells failed to prevent CM in the infected mice. They also observed that spleen cells from Breg recipient mice produced increased level of IL-10 in vitro. Cell co-culture study showed that the Bregs promoted IL-10 production by CD4⁺ T cells. These observations indicate that the IL-10-producing Bregs may represent an important mechanism in control of immunopathology that occues in brain tissue of malaria-infected host. Their work was recently published online in the European Journal of Immunology (2013，DOI: 10.1002/eji.201343512).