(28aj) A Microbead-Based Artificial Germinal Center (aGC) Model for the Proliferation and Differentiation of Human B Cells in Vitro

B cells are responsible for the antigen-specific humoral immunity with memory by differentiating into antibody-secreting plasma cells and memory B cells in response to a pathogenic infection. This differentiation occurs within specialized microenvironments called germinal centers (GCs) in the secondary lymphoid organs. Although several in-vitro methods for B cell differentiation have been successfully exploited to develop monoclonal antibody-based therapeutics against cancers and autoimmune diseases, there is the need for alternative cost-effective and high-volume culture of B cells with growing demand for effective vaccines against new infectious diseases and etc. To address this issue, we propose a feeder-free, artificial GC model in this presentation. We report that CD40 ligand presented on commercially-available iron oxide microbeads effectively sustained B cells in culture for up to 3 weeks, generated isotype-switched B cells that resemble the memory B or plasma cell phenotypes, and proliferated more than 50x. We confirmed that GC-like reactions are induced in our culture by the expression of activation-induced cytidine deaminase (AICDA) and EZH2 via RT-PCR. While studying the versatility of our approach by differentiating B cells from different donors, we confirmed that the donor’s smoking- and CMV-status might significantly influence B cell proliferation and differentiation, in coherence with prior immune response studies. Our future work will focus on further optimizing the activation signals and exploring alternative approaches to improve the yield of differentiated B cells.