Hematopoietic Stem Cells (HSCs) are able to differentiate into cells of two primary lineages, lymphoid and myeloid. Cells of the lymphoid lineage develop during the process of lymphopoiesis and include B Cells, T Cells, Natural Killer (NK) Cells, and Dendritic Cells. Many of these lymphocytes are short-lived, and immune system homeostasis requires continual HSC self-renewal and differentiation. R&D Systems provides multiple quality tools for HSC research including stem cell-specific media, kits for stem cell expansion, differentiation, and lineage depletion. We also offer a range of individual antibodies to study the expression of hematopoietic lineage-specific markers. Differentiated lymphocytes can be identified by analyzing the expression of specific cell surface markers, such as Cluster of Differentiation (CD) proteins and interleukin (IL) receptors. For example, Common Lymphoid Progenitor Cells express IL-7 R alpha/CD127, and differentiated B Cells can be identified by the expression of MS4A1/CD20.