title: Acidic isoferritin stimulates differentiation of normal granulomonocytic progenitors.
abstract: Acidic isoferritin (AIF) has been shown to be released by cells from patients with leukemia and to have an inhibitory effect on the growth of normal granulomonocytic (GM) progenitors (leukemia-inhibitory activity) during the S phase of the cell cycle. AIF is also produced by normal mature cells of the monocyte-macrophage lineage. We studied the effects of AIF on the differentiation of normal GM progenitors and found an increase in the number of mature cells in AIF-exposed cultures. This increase did not occur when AIF was pretreated with anti-heart ferritin antiserum or when basic isoferritin was used in the place of AIF. The influence of AIF was not mimicked by removing S phase cells by pretreatment with a pulse of high specific activity tritiated thymidine. Thus, the apparent differentiation-stimulating effect of AIF is not likely to be due to selective removal of immature dividing cells. The results suggest that AIF-inhibitory activity on the proliferation of GM progenitors might at least in part be mediated by a stimulus for differentiation of the target cells, thus regulating the number of mature cells which might be formed by a single progenitor cell.
authors.affiliation: Department of Haematology, Royal Free Hospital, London, U.K.
authors.forename: J E
authors.initials: JE
authors.lastname: Guimaraes
authors.forename: J J
authors.initials: JJ
authors.lastname: Berney
authors.forename: H E
authors.initials: HE
authors.lastname: Broxmeyer
authors.forename: A V
authors.initials: AV
authors.lastname: Hoffbrand
authors.forename: G E
authors.initials: GE
authors.lastname: Francis
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D005293:Ferritins; D006098:Granulocytes / Q000187:drug effects*; D006412:Hematopoietic Stem Cells / Q000187:drug effects
chemical_list: D003115:Colony-Stimulating Factors; C020391:acidic isoferritin; D005293:Ferritins