Rauch, Philipp J.Chudnovskiy, AlekseyRobbins, Clinton S.Weber, Georg F.Etzrodt, MartinHilgendorf, IngoTiglao, ElizabethFigueiredo, Jose-LuizIwamoto, YoshikoTheurl, IgorGorbatov, RosticWaring, Michael T.Chicoine, Adam T.Mouded, MajdPittet, Mikael J.Nahrendorf, MatthiasWeissleder, RalphSwirski, Filip K.2019-09-212012Rauch, P. J., A. Chudnovskiy, C. S. Robbins, G. F. Weber, M. Etzrodt, I. Hilgendorf, E. Tiglao, et al. 2012. “Innate Response Activator B Cells Protect Against Microbial Sepsis.” Science 335 (6068): 597–601. https://doi.org/10.1126/science.1215173.0036-80751095-9203http://nrs.harvard.edu/urn-3:HUL.InstRepos:41384252Recognition and clearance of a bacterial infection are fundamental properties of innate immunity. Here, we describe an effector B cell population that protects against microbial sepsis. Innate response activator (IRA) B cells are phenotypically and functionally distinct, develop and diverge from B1a B cells, depend on pattern-recognition receptors, and produce granulocyte-macrophage colony-stimulating factor. Specific deletion of IRA B cell activity impairs bacterial clearance, elicits a cytokine storm, and precipitates septic shock. These observations enrich our understanding of innate immunity, position IRA B cells as gatekeepers of bacterial infection, and identify new treatment avenues for infectious diseases.en-USJournal Article2019-09-2110.1126/science.1215173