A study of added GM-CSF independent granulocyte and macrophage precursors in mouse spleen infected with myeloproliferative sarcoma virus (MPSV)
Klein, B.; Le Bousse-Kerdiles, C.; Smadja-Joffe, F.; Pragnell, I.; Ostertag, W.; Jasmin, C.
Experimental Hematology 10(4): 373-382
1982
ISSN/ISBN: 0301-472X PMID: 6284533 Document Number: 191919
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.