Scientist STEMCELL Technologies Inc. Vancouver, British Columbia, Canada
Abstract: B cells play a crucial role in mounting rapid immune responses against pathogens and have the potential to be powerful tools for cell-based therapies. However, their use is limited by a lack of robust methods for in vitro generation. To address this, we developed a serum- and feeder-free culture system for generating B cells from human pluripotent stem cells (hPSCs). Utilizing hPSCs provides both an unlimited source of starting material and an opportunity for cell engineering. Human induced pluripotent stem cells derived from B cells (B-hiPSCs) provide a foundation for the generation of antigen-specific B cells as they possess a rearranged B cell receptor (BCR) and have undergone selection checkpoints in vivo. hPSCs were differentiated to CD34+ hematopoietic stem and/or progenitor cells (HSPCs) following a 12-day STEMdiff™ Hematopoietic - EB workflow, then were differentiated to B cells following a 5-week serum- and feeder-free protocol using StemSpan™ SFEM II medium and multi-stage B cell differentiation supplements. B-hiPSCs produced CD19+ B cells with a frequency of 72 ± 4% and a yield of 13 ± 6 cells per input CD34+ cell and CD19+IgG+ B cells with a frequency of 65 ± 5% and a yield of 11 ± 5 cells (mean ± SEM; n = 9). hPSC lines derived from other cell sources generated CD19+ B cells with a frequency of 19 ± 5% (n = 15) and CD19+IgM+ B cells with a frequency of 1.6 ± 0.5% (n = 15). B cells showed functional secretion of IgG or IgM antibodies by ELISpot assay, where B-hiPSC cultures generated 1,461 ± 247 (n = 3) antibody secreting cells (ASC) per 10,000 day 35 input cells. Non-B cell derived hPSCs generated 27 ± 20 IgM, and 19 ± 13 IgG ASCs per 10,000 day 35 input cells (n = 5). This novel serum- and feeder-free culture system generates hPSC-derived B cells that express and secrete antibodies. This work enables more efficient B lineage-specific research and provides a path to in vitro generation of B cells as potential tools in clinical applications.
