In vitro induction of human germinal center B cells.

In vitro, human naive B cells can be converted into GCB-like cells that display ongoing AID-dependent somatic hypermutation, recapitulating key features of natural germinal center B cells.

• Why it matters: Understanding human germinal center B cell biology has been limited by their tissue localization, hindering experimental manipulation and study of processes like affinity maturation and SHM.
• What they did: The authors developed a straightforward in vitro method modeling T cell signaling to generate induced GCB-like (iGCB) cells from naive B cells, and performed proteomic and transcriptional single-cell analyses comparing iGCB and human tonsil GCB cells.
• The result: The iGCB cells mimic natural GCB cells in surface markers, transcription factors, DNA repair, and glycosylation signatures, and can be used to define signals critical for GCB formation and potential interventions.