B cells are a subset of lymphocytes that express immunoglobulins on their cell surface. The B cell population is a vital component of the humoral immune response. B cell activation leads to antigen uptake and presentation, affinity maturation and class switching of the immunoglobulins, and antibody secretion. B cells represent a small portion (~5%) of the peripheral lymphocyte population making it difficult to obtain sufficient B cell quantities for many research applications. The ability to expand B cell populations ex vivo is valuable to researchers who require B cells for downstream applications including high throughput B cell assays and ex vivo differentiation of T cells.