12 research outputs found
Regulation of haemopoietic stemācell proliferation in mice carrying the Slj allele
We investigated a haemopoietic stromal defect, in mice heterozygous for the Slj allele, during haemopoietic stress induced by treatment with bacterial lipopolysaccharides (LPS) or lethal total body irradiation (TBI) and boneāmarrow cell (BMC) reconstitution. Both treatments resulted in a comparable haemopoietic stem cell (CFUās) proliferation in Slj/+ and +/+ haemopoietic organs. There was no difference in committed haemopoietic progenitor cell (BFUāe and CFUāG/M) kinetics after TBI and +/+ boneāmarrow transplantation in Slj/+ and +/+ mice. the Slj/+ mice were deficient in their ability to support macroscopic spleen colony formation (65% of +/+ controls) as measured at 7 and 10 days after BMC transplantation. However, the Slj/+ spleen colonies contained the same number of BFUāE and CFUāG/M as colonies from +/+ spleens, while their CFUās content was increased. On day 10 postātransplantation, the macroscopic āmissingā colonies could be detected at the microscopic level. These small colonies contained far fewer CFUās than the macroscopic detectable colonies. Analysis of CFUās proliferationāinducing activities in control and postāLPS sera revealed that Slj/+ mice are normal in their ability to produce and to respond to humoral stemācell regulators. We postulate that Slj/+ mice have a normal number of splenic stromal ānichesā for colony formation. However, 35% of these niches is defective in its proliferative support. Copyrigh