Mast cell colonies grew in methylcellulose when mouse spleen cells were cultured for 14 days in the presence of medium conditioned by concanavalin A-stimulated spleen cells. Tumor-promoting phorbol esters, 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12,13-didecanoate, enhanced the concanavalin A-stimulated spleen cell-conditioned medium-induced colony growth of mast cell progenitors....

mutation in a hemopoietic stem cell, burst-forming unit erythroid (BFU-E) colonies, colony-forming unit granulocyte-macrophage (CFU-GM), and colonyforming unit-eosinophil (CFU-Eo) were grown from a blood group 0 patient with a typical Tn syndrome displaying two distinct populations (Tn+ and Tn-) of platelets, granulocytes, and erythrocytes. A large number of colonies was observed. Individual co...

Several investigators have reported a retechnique. There was a marked decrease duction in the number of colony-forming in spleen CPU in these mice when cornunitsjCFU) in the sple.ns of mice exposed pared with control animals, but marrow to hypoxia and have postulated that this is CPU were not reduced. These tesults mdis.condary to a direct toxic effect of hypoxcafe that part of the effect of hy...

The growth capacity of femoral bone marrow stem cells from young and old long-lived mice was assessed in the spleen of X-irradiated young and old syngeneic recpients by determining: (a) the number of stem cells colonizing the spleen, (b) the rate of incorporation of 125I-labeled iododeoxyuridine by proliferating colony cells, and (c) the number of cells present in the largest colonies at the en...

The cobblestone-area forming cell (CAFC) assay permits a direct measurement of the seeding of primitive and more mature murine hematopoietic stem cell subsets by comparing the number of CAFC in the original transplant with the number of CAFC retrieved from bone marrow (BM) and spleen after transplantation. We found no differences in seeding efficiency between the more mature and primitive CAFC ...

Medium conditioned by activated T lymphocytes stimulates the in vitro proliferation of pluripotent hematopoietic stem cells (spleen colony-forming units [CFU-S]) but the factors involved have not been identified. Because the lymphokine interleukin 3 (IL-3) enhances in vitro colony formation by committed hematopoietic progenitor cells, we examined the effect of IL-3 on the in vitro proliferation...