Local regulation of haemopoietic stem cell proliferation in mice following irradiation.
Changes in the kinetic state of pluripotent haemopoietic spleen colony forming cells (CFU-S) and of the CFU-S proliferation stimulator have been studied following whole-body X-irradiation. Rapid recruitment of CFU-S into cell cycle by 30 min after irradiation was observed following low doses (0.5 Gy) but a delay of 6 h occurred after higher doses (1.5 and 4.5 Gy). These changes in proliferative state correlated with the presence of the CFU-S proliferation stimulator. CFU-S irradiated in vitro in bone marrow plugs were also recruited into cycle illustrating directly the local nature of the feedback mechanism. CFU-S removed from 1.5 Gy irradiated recipients at a time when they were not in cycle were not responsive to the CFU-S proliferation stimulator. The CFU-S proliferation stimulator was produced by Ia positive cells in the irradiated bone marrow. The regulation changes occurring shortly after irradiation cannot simply be controlled by the size of the CFU-S compartment.
Ali
A M
AM
Department of Biology & Preclinical Medicine, University of St Andrews, Scotland.
Wright
E G
EG
Riches
A C
AC
D000818:Animals; D000911:Antibodies, Monoclonal; D001854:Bone Marrow Cells; D002453:Cell Cycle / Q000528:radiation effects; D002455:Cell Division / Q000528:radiation effects; D046508:Culture Techniques; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000528:radiation effects*; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D008815:Mice, Inbred Strains; D013154:Spleen / Q000166:cytology; D014916:Whole-Body Irradiation
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II