Regulation by Lactoferrin of Epidermal Langerhans Cell Migration

Abstract

Lactoferrin is an iron-binding glycoprotein that shares structural homology with transferrin and which is found in milk, other epithelial secretions and the secondary granules of neutrophils¹. One function ascribed to lactoferrin is that of antibacterial activity which is effected primarily through the sequestration of iron necessary for microbial growth^1,2. It is recognized, however, that in addition to its bacteriostatic properties, lactoferrin may serve as a modulator of immune and inflammatory responses. Of particular interest is the observation that this glycoprotein may influence the production of some cytokines, including proinflammatory cytokines ^1–3. Among the cytokines shown to be regulated negatively by lactoferrin are tumour necrosis factor a (TNF-α), interleukin 1β (IL-1β) and granulocyte/macrophage colony-stimulating factor (GM-CSF)^2–4. It has been demonstrated that (bovine) lactoferrin administered intravenously to mice prior to an injection of bacterial lipopolysaccharide (LPS) inhibited significantly the production of TNF-α normally induced by LPS⁵. It has been argued, however, that the ability of lactoferrin to inhibit the stimulation of TNF-α by LPS may be secondary to its capacity to bind LPS and thereby compromise the signal for cytokine production³.