Hematopoietic Stem Cell

the cell from which all classes of blood cells are derived. It cannot be identified microscopically, but can be defined by the presence of a combination of cell-surface proteins. It can be demonstrated by tissue culture of the blood-forming tissue of the bone marrow, as well as by growth of human haemopoietic cells in immunodeficient mice strains, such as non-obese diabetic/severe combined immunodeficient (NOD/SCID). See also haemopoiesis .