Abstract
B cells are essential in the immune system, driving antibody production, cytokine secretion, and antigen presentation. Studies in mouse models have illuminated key mechanisms underlying B-cell activation, differentiation, class-switch recombination, and somatic hypermutation. However, the extent to which these findings translate to human biology remains unclear. To address this, we developed a human primary B-cell culture system using feeder cells engineered to express CD40L, supplemented with the cytokines BAFF, IL-4, and IL-21. Using a Design of Experiments (DOE) approach, we optimized critical parameters and dissected the individual contributions of each specific factor. Our results reveal that BAFF plays a negligible role, and IL-21 has more subtle effects, whereas CD40L and IL-4 are critical determinants of cell viability, proliferation and IgE class-switching. Furthermore, we find that engineered feeder cells can serve equally well as a source of cytokines, but providing these in purified form increases the flexibility of the system. This platform enables detailed investigation of human B-cell biology, offering insights into intrinsic and extrinsic regulators of antibody responses and providing a foundation for in vitro production of human primary antibodies.
Competing Interest Statement
JGM is a member of the Scientific Advisory Board of Nvelop Therapeutics. The company was not involved in the present study. The remaining authors declare no commercial or financial conflict of interest.
Abbreviations
- BCM
- B-Cell Medium
- BCR
- B-Cell Receptor
- CD40L
- CD40-ligand
- CSR
- Class-Switch Recombination
- DN
- double-negative
- DOE
- Design of Experiments
- GC
- Germinal Center
- IFN
- Interferon
- Ig
- Immunoglobulin
- iGB
- inducible Germinal Center B cell
- IL
- Interleukin
- MBC
- memory B cell
- NHDF
- Normal Human Dermal Fibroblasts
- PB
- plasma blast
- PC
- plasma cell
- SHM
- Somatic Hyper Mutation
- usMBC
- unswitched MBC.