Specificity and modulation of the action of lactoferrin, a negative feedback regulator of myelopoiesis

Abstract

The functional capacity of lactoferrin (LF) to act as a negative feedback regulator of myelopoiesis has been investigated and shown to depend on the structure of the molecule itself and on the presence and absence of agents that can modulate its activity. LF has a specific requirement for iron (Fe) in terms of its functional capacity and is most effective in inhibiting the production of granulocyte-macrophage colony stimulating activity (GM-CSA) from monocytes and macrophages when it is fully saturated with Fe. LF saturated with copper (Cu) or zinc (Zn) is functionally ineffective; moreover, Cu and Zn actually interfere with the inhibitory properties of Fe-saturated LF. A radioimmunoassay fo..