Identification of cells in primate bone marrow resembling the hemopoietic stem cell in the mouse

The colony forming unit culture (CFU C) in the thin layer agar colony technique is considered to be representative for hemopoietic stem cells (HSC), according to studies in mouse and monkey bone marrow. Using this in vitro assay as a guide, stem cell concentrates were prepared from monkey and human bone marrow by repeated density gradient centrifugation. The number of CFU C could be enriched up to 70-100 fold. In such concentrated CFU C suspensions, a cell, morphologically identical with the hemopoietic stem cell in the mouse (MSCLC, mouse stem cell like cell) was frequently observed, using a May Grunwald Giemsa (MGG) staining method and electron microscope techniques. In MGG stained preparations, the MSCLC superficially resembles the small lymphocyte; therefore, a staining method has been described, the polychrome procedure, by which both cell populations could be clearly distinguished. Since a fair correlation exists between the number of MSCLC and the number of CFU C in a variety of primate hemopoietic suspensions, it is concluded that the MSCLC might be a good candidate for being the HSC in monkeys and man. Chemicals/CAS: Agar, 9002-18-0; Serum Albumin, Bovin