title: A study of added GM-CSF independent granulocyte and macrophage precursors in mouse spleen infected with myeloproliferative sarcoma virus (MPSV).
abstract: A subpopulation of granulocyte and macrophage precursors (GM-CFUc) differentiating in the agar colony technique of Bradley and Metcalf into mature granulocytes and macrophages, without the addition of granulocyte and macrophage colony stimulating factor (GM-CSF), can be detected in MPSV infected mice. These precursors were detected 5 days after virus infection, reaching a maximal concentration of 1/10,000 spleen or bone marrow cells, 25 days after viral infection. The number of the added GM-CSF independent GM-CFUc was linearly correlated with the number of seeded MPSV hematopoietic cells. No GM-CSF producing cells could be detected in the MPSV spleen using normal bone marrow GM-CFUc as responder cells. Study of the GM-CSF sensitivity of the GM precursors has demonstrated the existence of two GM-CFUc populations in the MPSV spleen: a) a GM-CSF dependent population with a GM-CSF sensitivity similar to that of normal GM-CFUc b) a GM-CFUc population which differentiated in the absence of detectable amount of GM-CSF and of which differentiation was not affected by the addition of progressive amounts of GM-CSF. A possible model explaining these results is proposed.
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000187:drug effects; D003115:Colony-Stimulating Factors / Q000494:pharmacology / Q000502:physiology*; D006098:Granulocytes / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D008264:Macrophages / Q000166:cytology; D051379:Mice; D008811:Mice, Inbred DBA; D009053:Sarcoma Viruses, Murine; D012513:Sarcoma, Experimental / Q000473:pathology*; D013154:Spleen / Q000166:cytology*
chemical_list: D003115:Colony-Stimulating Factors