Survival of Human Bone Marrow Plasma Cells In Vitro Depends on the Support of the Stromal Cells, PI3K, and Canonical NF‐kappaB Signaling

Contrary to short-lived plasma cells, which survive only 3-5 days, long-lived plasma cells (LLPCs) contribute to the humoral memory of the body and thus also to many antibody-related diseases. The ability of plasma cells to persist over months, years, and even a lifetime has been demonstrated in vivo. Yet, the in vitro culture of human primary bone marrow-derived plasma cells has been limited to a few days. Here, we establish culture conditions for human primary bone marrow-derived plasma cells for 21 days. Plasma cells and stromal cells are isolated from human bone marrow and cultured in 2D or a 3D ceramic scaffold. The plasma cells' survival and antibody secretion depend on direct contact with stromal cells. The culture promotes CD19-negative PCs. Inhibition of the PI3K or NF-kappaB pathways using chemical inhibitors reduced the survival of the plasma cells. These results underline the supportive role of the stromal cells for the survival of the LLPC and confirm mechanisms that were identified in mouse LLPCs also for human LLPCs. The culture described here will promote further studies to deepen our understanding of the human LLPC.