title: Colony inhibiting factor in mature granulocytes from normal individuals and patients with chronic myeloid leukemia.
abstract: Inhibitory activity in extract from human blood granulocytes was tested on granulocyte-macrophage colony formation in vitro. The inhibition depended on the type of serum used. With mouse BMC and FCS in the cultures, extract corresponding to 2.5 X 10(4) granulocytes/ml reduced the colony number by 35%, and extract from 2 X 10(5) cells caused maximal inhibition (80-90%). With HS and mouse BMC the colony number was reduced by only 11-12%, but stronger inhibition (55%) was observed when the serum concentration was reduced. With both types of sera the total cell number per culture plate was reduced relatively more than the colony number. Human GM-CFC were as sensitive as mouse GM-CFC, and extract from CML granulocytes inhibited less (p less than 0.01) than extract from normal cells. Biochemical studies indicated that the inhibitor is a protein with a molecular weight of 30-60,000. Lactoferrin, a putative inhibitor of CSF production, did not inhibit spontaneous or CSF-induced colony formation in these studies.
mesh_terms: D000818:Animals; D002457:Cell Extracts / Q000032:analysis; D002470:Cell Survival; D002850:Chromatography, Gel; D003114:Colony-Forming Units Assay / Q000379:methods; D005260:Female; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007781:Lactoferrin / Q000494:pharmacology; D007951:Leukemia, Myeloid / Q000097:blood*; D008264:Macrophages / Q000166:cytology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011506:Proteins / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D002457:Cell Extracts; D011506:Proteins; C016313:colony inhibiting factor; D007781:Lactoferrin