An "old" cytokine's new trick: IL-1β in B cells and the germinal center.

IL-1β is typically associated with the innate response, often produced following the detection of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). It is also identified as a cytokine involved in bridging the innate and adaptive immune responses, in which innate cells, like dendritic cells, use IL-1β to activate T cells for the adaptive immune response. The role of IL-1 signaling has been established in the context of T cell differentiation and function, particularly in its regulation of T follicular helper (TFH) cells. Recent work has demonstrated that with TFH function primarily acting within the germinal center (GC), a local source of IL-1β must be present, identifying GC B cells as a critical source of IL-1β. Here we discuss the roles of cells within the GC milieu, the cytokines they produce, and their impact on the GC. In addition, we also discuss the findings from studies examining the molecular mechanisms underlying IL-1β production in B cells and its impact on B cell function. This review is especially relevant as it draws together findings from various disease pathologies to consolidate our current understanding of B cell subsets producing IL-1β and IL-1β signaling within the GC, in both T cells and B cells.