Non-canonical NF-κB signaling skews B cells away from germinal center to low-affinity effector fate

The non-canonical (NC) NF-κB pathway is a central regulator of B-cell development and survival, yet its role during B-cell mediated adaptive responses remains uncharted. Here, we uncover an unanticipated regulatory function for NC NF-κB in shaping humoral immunity. High-resolution mapping of NC NF-kB status in B cells from human lymphoid tissues revealed low activity in germinal center B-cells (GCB) than effector subsets, suggesting a selective attenuation. Consistently, mice model harboring B-cells with enforced NC NF-κB activation revealed near- complete loss of GCB and high-affinity antibodies, following vaccination. GCB loss was not driven by intrinsic defects in formation or expansion, but by an immune-niche dysregulation marked by regulatory T-cell expansion. Mechanistically, NC NF-κB activation promoted B-cell- derived IL-10, and blocking this axis normalize the niche and rescue GCB. Concurrently, NC NF- κB signaling boosted low-affinity antibody responses by transcriptionally priming follicular B- cells for plasmacytic differentiation. Together, these findings position NC NF-κB as a tunable rheostat linking B-cell signaling to immune-niche control and humoral immunity.

• Type: Transcriptome Analysis
• Archive: European Genome-phenome Archive (EGA)