Innate Response Activator B Cells Protect Against Microbial Sepsis

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Science  12 Jan 2012:
DOI: 10.1126/science.1215173


Recognition and clearance of bacterial infection is a fundamental property 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 GM-CSF. 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.