Multiple forms of lactoferrin in normal and leukemic human granulocytes.

Multiple forms of lactoferrin (Lf) were detected in granulocytes isolated from normal individuals and patients with granulocytic leukemias. One class of Lfs bound iron; a second class did not bind iron but possessed potent ribonuclease activity. The different forms of Lf were similar, if not identical, in their physical, chemical, and antigenic properties. The multiple forms of Lf may relate to the various functions ascribed to the molecule.