Colony‐forming Ability of Bone Marrow Cells of W Anaemic Mice on Macrophage Layer Formed in Peritoneal Cavity of Mice

Abstract

The colony‐forming ability of haematopoietic cells of W anaemic mice was examined on the macrophage layer formed in the peritoneal cavity of mice. Bone marrow cells of W anaemic mice formed a considerable number of colonies on the macrophage layer, notwithstanding they did not form any colonies in the spleen of the same recipients. As the colony‐forming ability of the bone marrow cells was not reduced by the incubation with 3H‐thymidine, most of the cells which formed colonies on the macrophage layer seemed to stay in G0 state. The interrelationship between the spleen colony‐forming cells, the macrophage‐layer colony‐forming cells, and in vitro colony‐forming cells was discussed.

Granulocytic colonies on macrophage‐coated membranes

“…The radiation survival Do curve for CFU-S of marrow origin has a shoulder [ l o ] , while we could demonstrate no shoulder for the CFU-ML. The radiation survival curve [ 111 , the effect of the S phase-specific cytotoxic agent [ 12,131 , and colony formation from W/W" marrow [8] are similar t o that seen in studies o f cells forming in vitro granulocytic colonies, CFU-C. Cells forming endogenous spleen colonies, E-CFU, which are presumed t o be pluripotent, are also sensitive t o cytosine arabinoside [14].…”

“…Sensitivity to S phase-specific cytosine arabinoside would suggest that CFU-ML are different from cells forming spleen colonies (CFU-S) [7] despite some similarity of the two with respect t o possible pluripotentiality and capability for stem cell competition [ 4 ] . The W/Wv produces normal-appearing granulocytic CFU-ML colonies [4,8], but has clearly abnormal CFU-S [9] . The radiation survival Do curve for CFU-S of marrow origin has a shoulder [ l o ] , while we could demonstrate no shoulder for the CFU-ML.…”