Hematopoietic Stem Cell Biology

All the cells in blood are derived from an adult stem cell that is found in the bone marrow called the Hematopoietic Stem Cell (HSC). In normal hematopoiesis (production of the cells in the blood), HSCs are continuously replenishing the blood by duplicating themselves and differentiating into progenitor cells that ultimately produce all the mature cells of the myeloid, lymphoid, and erythroid lineages, as well as platelets (megakaryocytes). HSCs are distinguished from progenitor cells by their ability to engraft long-term (decades) in the bone marrow and to produce all the mature cell types found in the blood. The Multipotent Progenitor (MPP) is the only progenitor cell that can also produce all mature cell types, but unlike the HSC, it cannot engraft long-term. More differentiated progenitor cells are only able to produce a subset of the cell types found in the blood. As shown in the schematic below, the Common Myeloid Progenitor (CMP) and Common Lymphoid Progenitor (CLP) arise from the MPP and each contributes to several mature cell types. The CMP produces cells of the innate immune system (granulocytes, monocytes, and dendritic cells), as well as red blood cells and platelets. The CLP produces lymphoid cells of both the innate (Natural Killer cells) and adaptive (T and B cells) immune systems.

The HSC and progenitor cell populations may be identified and isolated based on the unique panel of proteins expressed on the cell surface (phenotype). Cellerant's expertise in the characterization, isolation, and in vitro expansion of hematopoietic stem and progenitor cells has enabled us to develop several therapeutic cell products intended to treat serious hematopoietic conditions.

Schematic overview of normal human hematopoiesis of the myeloid and lymphoid lineages.
LT-HSC, Long-term hematopoietic stem cell; ST-HSC, Short-term HSC, MPP, Multipotent Progenitor; CLP, Common Lymphoid Progenitor; CMP, Common Myeloid Progenitor; MEP, Megakaryocyte Erythrocyte Progenitor; GMP, Granulocyte Monocyte Progenitor.
Based on Akashi K, et al. A clonogenic, common myeloid progenitor that gives rise to all myeloid lineages. Nature 2000; 404(6774): 193-7.


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