title: Endotoxin-induced changes in the interrelationship of density subpopulations of granulocyte-macrophage progenitor cells.
abstract: Progenitor cells of in vitro colonies of granulocytes and/or macrophages (CFU-s'c) constitute a functionally heterogeneous population reflected by differences in their bouyant density. The interrelationship of density subpopulations of murine (CFU-c, obtained by isopycnic centrifugatiuon of bone marrow cells in continuous albumin density gradients, was examined in perturbed states induced by endotoxin injection. Femoral bone marrow CFU-c's were investigated at daily intervals for 3 days after injection of endotoxin. A distinct difference was found between the changes in CFU-c when detected in vitro with MLCM and HU as the sources of CSF. After 1 day, there was a reduction in the number of CFU-c's, in particular by those CFU-c's of low density (< 1.07 gm/cm3) that are detectable in vitro with CSFMLCM and that form predominantly granulocytic colonies. This was followed on day 2 by the reappearance of this subpopulation. In contrast, those CFU-c's detectable with CSFHU and forming predominantly macrophage colonies were characterized by a high modal density (> 1.075 gm/cm3). Their numbers decreased on day 1, increased by day 2, and further increased above control levels by day 3 when they were characterized by a very high mean modal density of 1.087 gm/cm3. These results indicate that the different types of CSF detect subpopulations of CFU-c's that differ in differentiation potential and perhaps constitute a hierarchy in the myelopoietic pathway.
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002499:Centrifugation, Density Gradient; D003115:Colony-Stimulating Factors / Q000502:physiology; D004731:Endotoxins / Q000494:pharmacology*; D005260:Female; D005269:Femur / Q000166:cytology; D006098:Granulocytes / Q000166:cytology* / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000145:classification* / Q000502:physiology; D008264:Macrophages / Q000166:cytology* / Q000502:physiology; D051379:Mice
chemical_list: D003115:Colony-Stimulating Factors; D004731:Endotoxins