Bovine Lactoferrin Modulates Dendritic Cell Differentiation and Function

Abstract

Lactoferrin is an abundant glycoprotein in bovine milk that has immunomodulatory effects on human cells. Bovine lactoferrin (LF) binds lipopolysaccharides (LPS) with high affinity and is postulated to act via TLR4-dependent and -independent mechanisms. It has been shown that LF modulates differentiation of human monocytes into tolerogenic dendritic cells. However, in a previous study, we showed that LPS also mediates differentiation into tolerogenic dendritic cells (DC). Since LF binds LPS with high affinity, it remains to be investigated whether LF or LPS is mediating these effects. We, therefore, further investigated the LPS-independent effect of LF on differentiation of human monocytes into dendritic cells (DC). Human monocytes were isolated by magnetic cell sorting from freshly isolated PBMCs and cultured for six days in the presence of IL-4 and GM-CSF with or without LF or proteinase K treated LF to generate DC. These immature DC were stimulated for 48 h with LPS or Poly I:C + R848. Cell surface marker expression and cytokine production were measured by flow cytometry. DC differentiated in the presence of LF produced higher IL-6 and IL-8 levels during differentiation and showed a lower expression of CD1a and HLA-DR. These LFDCs showed to be hyporesponsive towards TLR ligands as shown by their semi-mature phenotype and reduced cytokine production. The effect of LF was abrogated by proteinase K treatment, showing that the functional effects of LF were not mediated by LPS contamination. Thus, LF alters DC differentiation and dampens responsiveness towards TLR ligands. This study indicates that LF can play a role in immune homeostasis in the human GI tract.

Lactoferrin: A Critical Player in Neonatal Host Defense

“…More recent data indicate a role for Lf in immune homeostasis as well. Studies indicate that DCs differentiated in the presence of Lf showed decreased responsiveness towards TLR ligands [ 88 , 89 ] and reduced cytokine production demonstrating a potential role for Lf in immune homeostasis. These results indicate a potent anti-inflammatory function for Lf by skewing monocyte differentiation into DCs with impaired capacity for activation and for promotion of Th1 responses and may represent a strategy to block excessive DC activation upon TLR-induced inflammation, adding further evidence for a critical role of Lf in directing host immune function.…”

Inclusion of Oat and Yeast Culture in Sow Gestational and Lactational Diets Alters Immune and Antimicrobial Associated Proteins in Milk

“…Lactoferrin (LTF), a normal component of milk and colostrum, which hyrdrolyzes RNA molecules, was also more abundant in milk of both yeast and oat supplemented sows. LTF functions to facilitate binding and transporting iron ions and has antibacterial, antiviral, and antiparasitic properties [ 83 , 84 ]. Enteral supplementation of preterm human infants with LTF was shown to reduce the effects of enteritis in neonates [ 85 ].…”

Enhanced Uptake of Processed Bovine β‐Lactoglobulin by Antigen Presenting Cells: Identification of Receptors and Implications for Allergenicity

“…The whey protein (WP) fraction was purified from the raw bovine milk as described before by Perdijk at al. [48] BLG was purified and isolated as described by De Jongh et al [49] using anion exchange chromatography DEAE Sepharose C-6B (GE healthcare, Chicago, IL, USA). Isolated BLG was lyophilized and of purity >94% was measured as described by Deng et al [20] The LPS removal was performed according to the protocol described by Teodorowicz et al [50] and the Recombinant Factor C Endotoxin Detection Assay (cat.…”

“…Isolation and Culturing of Monocyte-Derived Dendritic Cells (MoDCs): Peripheral blood mononuclear cells (PBMCs) were isolated by density centrifugation from fresh blood obtained from healthy anonymous donors as described previously. [48] Monocytes were differentiated into dendritic cells by culturing them for 6 days in the presence of 20 ng mL −1 IL-4 (Peptrotech; 200-04) and GM-CSF (Peprotech; 300-03). After 6 days, immature DCs were used for binding and internalization assays.…”