The influence of purified recombinant human heavy-subunit and light-
subunit ferritins on colony formation in vitro by granulocyte- macrophage
and erythroid progenitor cells
HE Broxmeyer, L Lu, DC Bicknell, DE Williams, S Cooper, S Levi, J Salfeld and P Arosio
Purified recombinant human heavy subunit (rHF, acidic) and recombinant
human light subunit (rLF, basic) ferritins were assessed for their effects
in vitro on colony formation by normal human granulocyte- macrophage
(CFU-GM) and erythroid (BFU-E) progenitor cells. The purity of the samples
was confirmed by electrophoresis in both nondenaturing and denaturing
conditions and silver staining. Concentrations of 10(-8) to 10(-10) mol/L
rHF caused an approximately 40% significant decrease in colony formation.
Some significant activity was detected at 10(-11) mol/L, and activity was
lost at 10(-12) mol/L. In contrast, rLF had no significant activity at
10(-8) to 10(-16) mol/L. rHF was significantly active against mouse bone
marrow CFU-GM to concentrations as low as 10(- 8) to 10(-9) mol/L. The
inhibitory activity of rHF was inactivated with three different monoclonal
antibodies recognizing the heavy subunit of ferritin, but not with two
monoclonal antibodies recognizing the light subunit of ferritin. The
inhibitory activity of rHF was similar in the absence or presence of serum,
monocytes, and T lymphocytes. We and others have shown an association of a
glycosylated natural acidic isoferritin (AIF) with inhibitory activity, but
since the rHF was expressed in Escherichia coli and did not bind to
concanavalin A, glycosylation of AIF is not an absolute prerequisite for
this activity. These results demonstrate that rHF has suppressive activity
in vitro and substantiate our original observations using purified natural
acidic isoferritins.
Volume 68,
Issue 6,
pp. 1257-1263,
12/01/1986
Copyright © 1986 by The American Society of Hematology
