Influence of Bovine Lactoferrin and Lactoferricin on Cytokine Expression in LPS-treated Cultivated Bovine Blood Cells

Lactoferrin (LF), an iron-binding glycoprotein, and a bactericidal pepsin-derived fragment of LF, lactoferricin (LFcin), are involved in host defense mechanisms via bacteriostatic activity and immuno-regulatory properties. The aim of this study was to investigate the effects of bovine LF and LFcin on the synthesis of immunologically important factors in leukocytes [white blood cells (WBC)] and monocytes. Monocytes were isolated from bovine blood using antibody-coated magnetic beads and cultured in parallel to WBC. Cells were treated with LF or LFcin and with Escherichia coli lipopolysaccharides (LPS). Various pro-inflammatory [tumor necrosis factor (TNF), interleukin-1 (IL-1) and IL-6] and anti-inflammatory (IL-10) cytokine mRNA expression responses were quantified via a one-step real-time reverse transcriptase polymerase chain reaction (RT-PCR). Furthermore, the gene expression for TNFα and IL-10 and the transcriptional activity of nuclear transcription factor kappa B (NF-κB) were measured after 0, 1, 2, 4 and 8 h. LF, LFcin and LPS strongly up-regulated the mRNA expression of all investigated cytokines, with peaks after 1 or 2 h for TNFα and IL-10. The magnitude of increase varied from modest (6-fold) to dramatic (64-fold). In contrast to LF and LPS treatment, LFcin induced a slight increase in TNFα mRNA in both cell culture types, which continued to be expressed at a higher level after 8 h. Compared with LPS-stimulated cells a combination of LF and LPS did not alter the TNFα and IL-10 expression. Simultaneous treatment of LFcin and LPS could increase the TNFα mRNA production, in contrast to LPS treatment alone. The effects of all agents used on cytokine mRNA expression were dose dependent. The NF-κB gene expression in monocytes and leukocytes was not affected by the treatment with LF and LFcin. The ability of LF and LFcin to bind free LPS and to interfere with the LBP/CD14 pathway has been suggested to restrain the activity of this bacterial immuno-stimulatory compound. These studies could not reveal these neutralizing effects because LF and LFcin showed no inhibitory activities on the cytokine production at several LPS concentrations. Copyright © 2005 Society of Chemical Industry