Lactoferrin and host defense

Histochemical properties of sialic acids and antimicrobial substances in canine anal glands

The functional properties of sialic acids appear to be manifold. Additionally, antimicrobial substances serve as a non-specific defense against microorganisms. In this study, therefore, the localization of sialic acids and antimicrobial substances in the anal glands of dog was studied by sialoglycoconjugate histochemistry and immunohistochemistry. The secretory epithelium, luminal secretions and excretory ducts exhibited high levels of sialoglycoconjugates that terminated in Siaα2-6Gal/GalNAc or Siaα2-3Gal1-4GlcNAc. Additionally, O-acetylated sialic acids were detectable in these glandular structures. Antimicrobial substances, such as lysozyme, immunoglobulin A (IgA), lactoferrin and the peptide group of β-defensins, were also demonstrated as products of the anal glands. The results obtained are discussed with regard to the functional significance of the anal glands. These secretory products may create a defensive barrier against microbial invasion at the anal mucosa.

Inhibition of tumor growth by recombinant adenovirus containing human lactoferrin through inducing tumor cell apoptosis in mice bearing EMT6 breast cancer

Human lactoferrin (hLTF), an 80-kDa iron-binding glycoprotein, has antitumor activity. In this study, a recombinant adenovirus containing the human lactoferrin cDNA (ad-rhLTF) was constructed and its effect on tumor growth was investigated in mice bearing EMT6 breast cancer. Ad-rhLTF was injected seven times within 14 days into the tumor site at two concentrations (10(8) and 5 × 10(8) pfu/mL) in mice bearing EMT6 breast cancer. Injected ad-rhLTF had considerable cytotoxicity on mice breast cancer, and significantly reducing the weight of tumor produced and increasing the tumor inhibition rate up to 52.64%. The presence of apoptotic cells was confirmed using TUNEL staining and flow cytometry assays. At the same time, RTPCR and Western blot analyses demonstrated that ad-rhLTF also decreased expression of Bcl-2 and increased Bax and caspase 3 expressions. Therefore, we conclude that ad-rhLTF inhibits tumor growth by inducing tumor cell apoptosis in mice with breast cancer by triggering the mitochondrial-dependent pathway and activation of caspase 3. The results indicate that ad-rhLTF might be a promising drug for breast cancer gene therapy.

Efficacy and tolerability of oral lactoferrin supplementation in mild to moderate acne vulgaris: an exploratory study

OBJECTIVE

Lactoferrin, an innate defense iron-binding protein, possesses antimicrobial and anti-inflammatory activities. Beneficial systemic effects on inflammatory diseases have been proposed. The aim of the present study was to explore the efficacy and tolerability of oral bovine lactoferrin supplementation in subjects with mild to moderate facial acne vulgaris.

METHODS

In this open-label, single-arm study, 43 adolescents and young adults were enrolled to take a chewable tablet formulation of bovine lactoferrin twice daily for 8 weeks. The primary efficacy endpoint was the improvement in acne lesion counts compared with baseline. Tolerability was evaluated on the basis of adverse event frequencies.

RESULTS

Thirty-nine subjects, aged 17.5 ± 3.8 years, completed the study per protocol. At the end of the study (week 8), a mean reduction in inflammatory lesion count of 20.2% (-2.2 ± 7.0, p = 0.054), in non-inflammatory lesion count of 23.5% (-6.2 ± 9.8, p < 0.001), and in total lesion count of 22.5% (-8.4 ± 13.1, p < 0.001) was observed as compared with baseline. At study conclusion, 76.9% (30 of 39) of subjects showed a reduction in total lesion count. The results for inflammatory acne lesions were variable over the study course. None of the subjects experienced a lactoferrin-related adverse event during the trial.

CONCLUSION

Despite the limitations of an uncontrolled, open-label study, the results from this study indicate that lactoferrin in mild to moderate acne vulgaris is well tolerated and may lead to an overall improvement in acne lesion counts in the majority of affected adolescents and young adults when administered as a dietary supplement on a twice daily regimen. Further randomized, placebo-controlled trials of longer duration appear warranted.

In vitro lung delivery of bacteriophages KS4-M and ΦKZ using dry powder inhalers for treatment of Burkholderia cepacia complex and Pseudomonas aeruginosa infections in cystic fibrosis

AIMS

To determine the feasibility of formulating and aerosolizing powders containing bacteriophages KS4-M and ΦKZ for lung delivery and treatment of pulmonary Burkholderia cepacia complex and Pseudomonas aeruginosa infections.

METHODS AND RESULTS

Endotoxin-removed bacteriophages KS4-M and ΦKZ were lyophilized in lactose/lactoferrin 60 : 40 w/w matrix and deagglomerated in a mixer mill (without beads) to formulate respirable powders. The powders were then aerosolized using an Aerolizer(®) capsule inhaler. Mass median aerodynamic diameter (MMAD) of this inhalable aerosol was determined using Andersen cascade impactor at 60 l min(-1). Measured MMAD for both types of powders was 3·4 μm, and geometric standard deviation was 1·9-2·0. Viability of bacteriophages delivered distal to an idealized mouth-throat replica was determined from bioassays of samples collected on filters placed after the idealized replica. As a percentage of inhaler load, amount of powder delivered distal to the mouth-throat replica, which is a measure of lung delivery, was 33·7 ± 0·3% for KS4-M and 32·7 ± 0·9% for ΦKZ. Titres collected downstream of the mouth throat were (3·4 ± 2·5) × 10(6) PFU for KS4-M with an Aerolizer capsule load of (9·8 ± 4·8) × 10(6) and (1·9 ± 0·6) × 10(7) for ΦKZ with an Aerolizer capsule load of (6·5 ± 1·9) × 10(7).

CONCLUSIONS

Bacteriophages KS4-M and ΦKZ can be lyophilized without significant loss of viability in a lactose/lactoferrin 60 : 40 w/w matrix. The resulting powders can be aerosolized to deliver viable bacteriophages to the lungs.

SIGNIFICANCE AND IMPACT OF THE STUDY

  Development of lactoferrin-based bacteriophage aerosol powders solidifies the ground for future research on developing novel formulations as an alternative to inhaled antibiotic therapy in patients with cystic fibrosis.

Human lactoferrin activates NF-kappaB through the Toll-like receptor 4 pathway while it interferes with the lipopolysaccharide-stimulated TLR4 signaling

Lactoferrin (LF) has been implicated in innate immunity. Here we reveal the signal transduction pathway responsible for human LF (hLF)-triggered nuclear factor-kappaB (NF-kappaB) activation. Endotoxin-depleted hLF induces NF-kappaB activation at physiologically relevant concentrations in the human monocytic leukemia cell line, THP-1, and in mouse embryonic fibroblasts (MEFs). In MEFs, in which both tumor necrosis factor receptor-associated factor 2 (TRAF2) and TRAF5 are deficient, hLF causes NF-kappaB activation at a level comparable to that seen in wild-type MEFs, whereas TRAF6-deficient MEFs show significantly impaired NF-kappaB activation in response to hLF. TRAF6 is known to be indispensable in leading to NF-kappaB activation in myeloid differentiating factor 88 (MyD88)-dependent signaling pathways, while the role of TRAF6 in the MyD88-independent signaling pathway has not been clarified extensively. When we examined the hLF-dependent NF-kappaB activation in MyD88-deficient MEFs, delayed, but remarkable, NF-kappaB activation occurred as a result of the treatment of cells with hLF, indicating that both MyD88-dependent and MyD88-independent pathways are involved. Indeed, hLF fails to activate NF-kappaB in MEFs lacking Toll-like receptor 4 (TLR4), a unique TLR group member that triggers both MyD88-depependent and MyD88-independent signalings. Importantly, the carbohydrate chains from hLF are shown to be responsible for TLR4 activation. Furthermore, we show that lipopolysaccharide-induced cytokine and chemokine production is attenuated by intact hLF but not by the carbohydrate chains from hLF. Thus, we present a novel model concerning the biological function of hLF: hLF induces moderate activation of TLR4-mediated innate immunity through its carbohydrate chains; however, hLF suppresses endotoxemia by interfering with lipopolysaccharide-dependent TLR4 activation, probably through its polypeptide moiety.

Functional properties of feline foot pads as studied by lectin histochemical and immunohistochemical methods

The localization of sialic acids and antimicrobial substances in the foot pads of the cat was examined by lectin histochemical and immunohistochemical methods. The lectin binding patterns of the eccrine glands were suggestive of the existence of large concentrations of sialoglycoconjugates that terminated in Siaalpha2-3Gal1-4GlcNAc. Results were consistent with localization of O-linked (mucin-type) sialoglycoproteins with the Siaalpha2-6Gal/GalNAc sequence in the epidermal layers, especially the stratum spinosum. Additionally, antimicrobial peptides, such as lysozyme, secretory component, lactoferrin, and the peptide group of beta-defensins were demonstrated to be immunolocalised in the eccrine glandular cells. These substances, except for secretory component, were also distributed in the epidermal strata. The sialic acids and antimicrobial substances found in the eccrine glandular secretions and epidermis may play an essential role in the preservation of skin integrity in feline foot pads.

Immunoregulatory role of lactoferrin-lipopolysaccharide interactions

Lactoferrin (Lf) is a mammalian exclusive protein widely distributed in milk and exocrine secretions exhibiting multifunctional properties. Many of the proven or proposed functions of Lf, apart from its iron binding activity, depend on its capacity to bind to other macromolecules. Lf can bind and sequester lipopolysaccharide (LPS), thus preventing pro-inflammatory pathway activation, sepsis and tissue damage. However, the interplay between Lf and LPS is complex, and may result in different outcomes, including both suppression of the inflammatory response and immune activation. These findings are critically relevant in the development of Lf-based therapeutic interventions in humans. Understanding the molecular basis and functional consequences of Lf-LPS interaction will provide insights for determining its role in health and disease.

A novel polypeptide derived from human lactoferrin in sodium hyaluronate prevents postsurgical adhesion formation in the rat

OBJECTIVE

The objective of the study was to evaluate whether a peptide derived from human lactoferrin, PXL01 could act safely to reduce the formation of peritoneal adhesions in the rat model and to map the molecular mechanisms of its action.

SUMMARY BACKGROUND DATA

Adhesion formation is a significant problem within every surgical discipline causing suffering for the patients and major cost for the society. For many decades, attempts have been made to reduce postsurgical adhesions by reducing surgical trauma. It is now believed that major improvements in adhesion prevention will only be reached by developing dedicated antiscarring products, which are administrated in connection to the surgical intervention.

METHODS

Anti-inflammatory as well as fibrinolytic activities of PXL01 were studied in relevant human cell lines. Using the sidewall defect-cecum abrasion model in the rat, the adhesion prevention properties of PXL01 formulated in sodium hyaluronate were evaluated. Large bowel anastomosis healing model in the rat was applied to study if PXL01 would have any negative effects on intestine healing.

RESULTS

PXL01 exhibits an inhibitory effect on the most important hallmarks of scar formation by reducing infections, prohibiting inflammation, and promoting fibrinolysis. PXL01 formulated in sodium hyaluronate markedly reduced formation of peritoneal adhesions in rat without any adverse effects on wound healing.

CONCLUSIONS

A new class of synthetically derived water soluble low molecular weight peptide compound, PXL01 showed marked reduction of peritoneal adhesion formation in an animal model without any negative effects on healing. On the basis of these data, a comprehensive adhesion prevention regimen in clinical situation is expected.

Comparison of milk fat globule membrane (MFGM) proteins of Chianina and Holstein cattle breed milk samples through proteomics methods

Identification of proteins involved in milk production is important to understand the biology of lactation. Many studies have advanced the understanding of mammary function and milk secretion, but the critical molecular mechanisms implicated in milk fat secretion is still incomplete. Milk fat globules are secreted from the apical surface of the mammary cells, surrounded by a thin membrane bilayer, the milk fat globule membrane (MFGM), formed by proteins which have been suggested to be cholesterolemia-lowering factors, inhibitors of cancer cell growth, vitamin binders, bactericidal, suppressors of multiple sclerosis. Using a proteomic approach, we compared MFGM from milk samples of individuals belonging to two different cattle breeds, Chianina and Holstein, representative of selection for milk and meat traits, respectively. We were able to isolate some of the major MFGM proteins in the examined samples and to identify differences between the protein fractions of the two breeds. We detected differences in the amount of proteins linked to mammary gland development and lipid droplets formation, as well as host defence mechanisms. We have shown that proteomics is a suitable, unbiased method for the study of milk fractions proteins and a powerful tool in nutritional genomics.

Decreased circulating lactoferrin in insulin resistance and altered glucose tolerance as a possible marker of neutrophil dysfunction in type 2 diabetes

CONTEXT

Lactoferrin is an innate immune system protein with multiple beneficial health activities.

OBJECTIVE

To gain insight in the interaction between innate immune system and metabolic disturbances (obesity and insulin resistance), we investigated the relationship between circulating lactoferrin and chronic inflammation-associated insulin resistance according glucose tolerance status in Caucasian population.

DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME MEASURES

Circulating nonstressed lactoferrin (ELISA), metabolic variables, and inflammatory markers were measured in 229 men, 94 with normal (NGT) and 135 with altered glucose tolerance (AGT). Lactoferrin secretion by neutrophil was investigated in whole-blood culture (four young NGT subjects, four older NGT subjects, and four patients with type 2 diabetes) under microbial lipopolysaccharide (LPS) with IL-6 and rosiglitazone treatment. We also tested the lactoferrin action in THP-1 cells under LPS stimulus.

RESULTS

Circulating lactoferrin was significantly decreased in patients with AGT (431.5 +/- 187.5 vs. 493.5 +/- 238.9 ng/ml, P = 0.02). In addition, circulating lactoferrin was negatively associated with hyperglycemia and obesity measures and positively with insulin sensitivity. Lactoferrin was negatively related to inflammatory markers, especially in AGT subjects. In ex vivo experiments, we found a significant decrease in LPS-induced lactoferrin release from neutrophils in subjects with type 2 diabetes. IL-6 coincubation decreased LPS-induced lactoferrin release in NGT subjects (P < 0.001). Finally, rosiglitazone treatment led to increased lactoferrin secretion (398 +/- 193 vs. 280.1 +/- 104.9 ng/ml, P < 0.0001). Lactoferrin decreased nuclear factor-kappabeta activation and IL-6, IL-8, and macrophage chemoattractant protein-1 expression under LPS challenge.

CONCLUSIONS

Decreased circulating lactoferrin levels may play a role in chronic low level inflammation-associated insulin resistance.

Expression of three intelectins in sheep and response to a Th2 environment

Sheep intelectin1 and sheep intelectin3 (sITLN1 and sITLN3) were cloned and sequenced. The amino acid sequences of sITLN1 and sITLN3 shared 86% and 91% homology with the previously cloned sheep intelectin2 (sITLN2), respectively. Expression of sITLN1 and sITLN3 transcript was demonstrated in abomasum, lung, colon and gastric lymph node, terminal rectum, skin, jejunum, mesenteric lymph node, ileal peyer’s patches, brain, kidney, liver, spleen, skin, ear pinna, heart and ovary in normal sheep tissues. sITLN2 transcript expression was restricted to the abomasal mucosa in normal sheep tissues. Using a non selective chicken anti-intelectin antibody, tissue intelectin protein was demonstrated in mucus neck cells in the abomasum, mucus cells in the colon, free mucus in ileum, goblet cells in the lung, small intestinal epithelium and brush border, epidermal layer of the skin and skin sebaceous glands. The expression of the three sITLN transcripts was examined in two nematode infections in sheep known to induce a Th2 response; a Teladorsagia circumcincta challenge infection model and a Dictyocaulus filaria natural infection. The three sITLN were absent in unchallenged naïve lambs and present in the abomasal mucosa of both naïve and immune lambs following T. circumcincta challenge infection. Upregulation of sITLN2 and sITLN3 was shown in sheep lung following D. filaria natural infection. Intelectins may play an important role in the mucosal response to nematode infections in ruminants.

Biofilms in wounds: management strategies

Biofilms probably induce a chronic and/or 'quiet' inflammation in the chronic wound and so delay healing. This paper reviews current strategies that can be used to suppress biofilms in chronic wounds until better options are available.

Lactoferrin and cancer disease prevention

Lactoferrin (LF) is an iron-binding glycoprotein that is composed of the transferrin family and is predominantly found in the products of the exocrine glands located in the gateways of the digestive, respiratory, and reproductive systems, suggesting a role in the non-specific defence against invading pathogens. Additionally, several physiological roles have been attributed to LF, namely regulation of iron homeostasis, host defence against infection and inflammation, regulation of cellular growth, and differentiation and protection against cancer development and metastasis. These findings have suggested LF's great potential therapeutic use in cancer disease prevention and/or treatment, namely as a chemopreventive agent. This review looks at the recent advances in understanding the mechanisms underlying the multifunctional roles of LF and future perspectives on its potential therapeutic applications.

Proteomic profiling in early venous stenosis formation in a porcine model of hemodialysis graft

PURPOSE

To use proteomic analysis to identify up- and downregulated proteins in early venous stenosis formation in a porcine model of hemodialysis graft failure.

MATERIALS AND METHODS

Pigs had chronic renal insufficiency created by subtotal renal infarction caused by renal artery embolization. Arteriovenous polytetrafluoroethylene grafts were placed 28 days later and the animals were killed after a further 3 days (n = 4), 7 days (n = 4), or 14 days (n = 4). Proteomic analysis with isotope-coded affinity tags and multidimensional liquid chromatography followed by tandem mass spectrometry was performed on the venous stenosis and control vessels. Expression of proteins was further confirmed by Western blot analysis. The blood urea nitrogen (BUN) and creatinine levels were determined before renal artery embolization and at the time of graft placement.

RESULTS

At graft placement, mean BUN and creatinine levels were significantly higher than before embolization (P < .05). Six proteins were identified that were common to all four animals at the same time point. Five proteins (alpha-fetoprotein, fetuin A, macrophage migration inhibitory factor, pyruvate dehydrogenase E1 component, and lactoferrin) were upregulated and one protein (decorin) was downregulated. Expression of macrophage migration inhibitory factor, alpha-fetoprotein, and lactoferrin was further validated with Western blotting. By day 14, lactoferrin and fetuin-A expression were increased significantly in early venous stenosis formation.

CONCLUSIONS

Significantly increased expression of lactoferrin and fetuin-A were observed in early venous stenosis by day 14. Understanding the role of lactoferrin and fetuin-A in hemodialysis vascular access failure could help in improving outcomes in patients undergoing hemodialysis.

Conformational changes in bovine lactoferrin induced by slow or fast temperature increases

Lactoferrin (LF) is an iron-binding protein present in several secreted substances, such as milk, and has broad antimicrobial and physiological properties. Because high temperatures may affect protein stability and its functional properties, we investigated the effect of heat on bovine LF structure and stability. The effects of temperatures used during the pasteurization process on LF and its relationship to protein functionality were studied. Conformational changes were monitored using spectroscopic techniques, such as circular dichroism (CD) and fluorescence spectroscopy. The CD data at 70°C showed that LF's secondary structure is drastically and irreversibly affected when the temperature is gradually increased. The same effect is observed when the temperature is gradually raised from 25°C to 105°C and changes are monitored by tryptophan fluorescence emission. We also verified the effects of simulating the pasteurization process; LF remained well structured during the entire process and this result was not time-dependent. Owing to preservation of the secondary structure with changes in the tertiary structure, we thus believe that pasteurization might cause LF to change into an intermediate partially folded state. A better understanding of heat stability is important for the use of LF as a bioactive component in food.

A study of biofilm-based wound management in subjects with critical limb ischaemia

OBJECTIVE

Bacterial biofilms cause or complicate numerous medical conditions, including chronic wounds. Biofilm-based wound care (BBWC) management strategies that suppress biofilm have been designed and are used extensively at the Southwest Regional Wound Care Center in Lubbock, Texas and are described in this article. This retrospective single-centre study was designed to evaluate the frequency of complete healing in subjects with a chronic wound in a limb with critical limb ischaemia (CLI) when managed using BBWC.

METHOD

Of the 4500 subjects admitted with wounds between August 2002 and January 2006, 1400 subjects' TCpO2 levels were measured, and 266 included were identified as having CLI (TCpO2 < 20mmHg). Of these, 190 subjects were considered in the analysis because they received a substantial course of therapy (more than five visits). Each subject was individually managed to reinforce natural healing and suppress bacterial biofilm. Successful healing was defined as complete closure by March 2007.

RESULTS

Of the 190 subjects with CLI, 146 (77%) healed completely, and 44 (23%) were categorised as non-healing. The healed group included 47% (68/146) with osteomyelitis and 69% (101/146) with diabetes mellitus. In the non-healed group, 75% (33/44) had osteomyelitis and 77% (34/44) had diabetes mellitus. Ninety-one per cent (30/33) of the subjects without osteomyelitis or diabetes mellitus healed, and 67% (53/79) of the subjects with both osteomyelitis and diabetes mellitus healed.

CONCLUSION

When comparing the healing frequency in this study with a previously published study, BBWC strategies significantly improved healing frequency. These findings demonstrate that effectively managing the biofilm in chronic wounds is an important component of consistently transforming 'non-healable' wounds into healable wounds.

Comparative antibacterial activity of avian egg white protein extracts

1. Egg white proteins from the eggs of domestic chicken (Gallus gallus), turkey (Meleagris gallopavo), duck (Anas platyrhynchos) and goose (Anser anser) were analysed in order to compare the antimicrobial activity of these products. 2. Albumen from each species was sampled and analysed by SDS-PAGE and Western blotting. Antimicrobial activity and lysozyme activity were measured. 3. Ovotransferrin and ovalbumin were identified in all species while c-type lysozyme was present in chicken, turkey and duck egg white samples, but not in goose. 4. Galliformes appear to possess albumens with greater antimicrobial activity than those of the Anseriformes. This can be attributed to higher concentrations of ovotransferrin and the broad acting c-type lysozyme.

Influence of bovine lactoferrin on expression of presentation molecules on BCG-infected bone marrow derived macrophages

The current vaccine for tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), is an attenuated strain of Mycobacterium bovis bacillus Calmette-Guerin (BCG). BCG has proven to be effective in children, however, efficacy wanes in adulthood. Lactoferrin, a natural protein with immunomodulatory properties, is a potential adjuvant candidate to enhance efficacy of BCG. These studies define bovine lactoferrin as an enhancer of the BCG vaccine, functioning in part by modulating macrophage ability to present antigen and stimulate T-cells. BCG-infected bone marrow derived macrophages (BMMs) cultured with bovine lactoferrin increased the number of MHC II(+) expressing cells. Addition of IFN-gamma and lactoferrin to BCG-infected BMMs enhanced MHC II expressiona dna increased the ratio of CD86/CD80. Lactoferrin treated BCG-infected BMMs were able to stimulate an increase in IFN-gamma production from presensitized CD3(+) splenocytes. Together, these results demonstrate that bovine lactoferrin is capable of modulating BCG-infected macrophages to enhance T-cell stimulation through increased surface expression of antigen presentation and co-stimulatory molecules, which potentially explains the observed in vivo bovine lactoferrin enhancement of BCG vaccine efficacy to protect against virulent MTB infection.

Stimulus-dependent impairment of the neutrophil oxidative burst response in lactoferrin-deficient mice

Lactoferrin (LF) is an iron-binding protein found in milk, mucosal secretions, and the secondary granules of neutrophils in which it is considered to be an important factor in the innate immune response against microbial infections. Moreover, LF deficiency in the secondary granules of neutrophils has long been speculated to contribute directly to the hypersusceptibility of specific granule deficiency (SGD) patients to severe, life-threatening bacterial infections. However, the exact physiological significance of LF in neutrophil-mediated host defense mechanisms remains controversial and has not yet been clearly established in vivo using relevant animal models. In this study, we used lactoferrin knockout (LFKO) mice to directly address the selective role of LF in the host defense response of neutrophils and to determine its contribution, if any, to the phenotype of SGD. Neutrophil maturation, migration, phagocytosis, granule release, and antimicrobial response to bacterial challenge were unaffected in LFKO mice. Interestingly, a stimulus-dependent defect in the oxidative burst response of LFKO neutrophils was observed in that normal activation was seen in response to opsonized bacteria whereas an impaired response was evident after phorbol myristate-13-acetate stimulation. Taken together, these results indicate that although LF deficiency alone is not a primary cause of the defects associated with SGD, this protein does play an immunomodulatory role in the oxidative burst response of neutrophils.

IsdA protects Staphylococcus aureus against the bactericidal protease activity of apolactoferrin

An important facet of the Staphylococcus aureus host-pathogen interaction is the ability of the invading bacterium to evade host innate defenses, particularly the cocktail of host antimicrobial peptides. In this work, we showed that IsdA, a surface protein of S. aureus which is required for nasal colonization, binds to lactoferrin, the most abundant antistaphylococcal polypeptide in human nasal secretions. The presence of IsdA on the surface of S. aureus confers resistance to killing by lactoferrin. In addition, the bactericidal activity of lactoferrin was inhibited by addition of phenylmethylsulfonyl fluoride, implicating the serine protease activity of lactoferrin in the killing of S. aureus. Recombinant IsdA was a competitive inhibitor of lactoferrin protease activity. Reciprocally, antibody reactive to IsdA enhanced killing of S. aureus. Thus, IsdA can protect S. aureus against lactoferrin and acts as a protease inhibitor.

The use of lactoferrin as a ligand for targeting the polyamidoamine-based gene delivery system to the brain

Development of an efficient gene vector is a key-limiting factor of brain gene therapy. In this study, lactoferrin (Lf), for the first time, was investigated as a brain-targeting ligand in the design of polyamidoamine (PAMAM)-based non-viral gene vector to the brain. Using polyethyleneglycol (PEG) as a spacer, PAMAM-PEG-Lf was successfully synthesized. This vector showed a concentration-dependent manner in the uptake in brain capillary endothelial cells (BCECs). The brain uptake of PAMAM-PEG-Lf was 2.2-fold compared to that of PAMAM-PEG-transferrin (Tf) in vivo. The transfection efficiency of PAMAM-PEG-Lf/DNA complex was higher than that of PAMAM-PEG-Tf/DNA complex in vitro and in vivo. The results of frozen sections showed the widespread expression of an exogenous gene in mouse brain via intravenous administration. With a PAMAM/DNA weight ratio of 10:1, the brain gene expression of the PAMAM-PEG-Lf/DNA complex was about 2.3-fold when compared to that of the PAMAM-PEG-Tf/DNA complex. These results provide evidence that PAMAM-PEG-Lf can be exploited as a potential non-viral gene vector targeting to the brain via noninvasive administration. Lf is a promising ligand for the design of gene delivery systems targeting to the brain.

Changes in salivary proteome following allogeneic hematopoietic stem cell transplantation

OBJECTIVE

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is frequently complicated by severe infections and graft-vs-host disease (GVHD). Saliva contains many components of adaptive and innate immune response crucial for local host defenses. Changes in salivary constituents could reflect systemic processes such as immune reconstitution and development of GVHD that occur posttransplant. This study was an initial evaluation of salivary protein changes that occur after allo-HCT.

PATIENTS AND METHODS

Serially collected saliva samples from 41 patients undergoing allo-HCT were evaluated. Changes in salivary proteome were initially examined by SELDI-TOF mass spectrometry. Individual protein changes were identified by 2-dimensional differential in-gel electrophoresis (2D-DIGE) with subsequent MS/MS sequencing and ELISA.

RESULTS

Significant increases and decreases in multiple salivary proteins that lasted at least 2 months posttransplant were detected by SELDI-TOF mass spectrometry. Lactoferrin and secretory leukocyte protease inhibitor demonstrated elevations 1 month post-HCT that persisted at least 6 months. Secretory IgA (sIgA) levels were decreased 1 month posttransplant, with recovery at approximately 6 months. Levels of salivary beta(2)-microglobulin were elevated at 6 months and correlated with sIgA levels.

CONCLUSION

Allo-HCT is associated with long-term changes in several salivary proteins important for innate immune responses. These results support further studies on the association of salivary proteins with posttransplant complications including infections and GVHD.

Lactoferrin Glu561Asp polymorphism is associated with susceptibility to herpes simplex keratitis

Lactoferrin plays an important role in the defense against infections, including herpes simplex virus (HSV) keratitis. We studied the impact of three single nucleotide polymorphisms in the human lactoferrin gene on the susceptibility to HSV infections of the eye and the severity of such infections. Lactoferrin gene polymorphisms were determined by PCR combined with restriction fragment length analysis in 105 HSV keratitis patients and 145 control subjects. Bilateral tear samples were harvested from 50 patients and 40 healthy controls and tear lactoferrin concentrations were determined by ELISA. Patients' records were used to acquire information about the severity of the HSV keratitis. The frequencies of the Glu561Asp polymorphism, but not those of the Ala11Thr and Lys29Arg polymorphisms, differed significantly between patients and control subjects with an under-representation of the Asp561 allele in the patient group. Furthermore, the values for best corrected visual acuity, frequency of recurrences since onset, and average duration of clinical episodes did not differ among patients with various lactoferrin genotypes. In addition, tear lactoferrin concentrations were the same in patients with HSV keratitis and healthy controls and also did not differ among patients with various lactoferrin genotypes. Lactoferrin Glu561Asp polymorphism is associated with the susceptibility to HSV keratitis with a protective role for lactoferrin variants comprising Asp561. However, no beneficial effects of this lactoferrin variant on the clinical outcome of ocular HSV keratitis were noted.

Effect of dietary lactoferrin on the immune functions and serum iron level of weanling piglets

A total of 90 weanling female pigs (Duroc x Landrace x Yorkshire) were used in a 30-d growth experiment to investigate the effect of lactoferrin (LF) on growth performance, immune function, and serum iron concentrations. The pigs were allocated on the basis of BW and litter to 3 dietary treatments in a randomized complete block design. The dietary treatments were: control group (basal diet), antibiotics group (basal diet + 20 mg/kg of flavomycin + 110 mg/kg of aureomycin), and LF group (basal diet + 1.0 g/kg of LF). There were 3 replicate pens per treatment, and pigs were grouped with 10 pigs per pen. Six pigs, randomly selected from each treatment (2 pigs/pen), were slaughtered for serum and spleen samples on d 15 and 30. Supplementation with LF improved the phytohemagglutinin (PHA)-stimulated peripheral lymphocyte proliferation by 36% (P < 0.01), increased concanavalin A (ConA)- and PHA-induced spleen lymphocyte proliferation by 332% (P < 0.01) and 258% (P < 0.01), enhanced serum IgG by 20% (P < 0.05), IgA by 13% (P < 0.05), IgM by 15% (P < 0.05), complement 4 (C4) by 29% (P < 0.05), IL-2 by 12% (P < 0.01), and serum iron values by 22% (P < 0.05) on d 15 compared with the control. Lactoferrin supplementation increased PHA-stimulated lymphocyte proliferation (P < 0.01), serum IgG by 16% (P < 0.05), IgA by 17% (P < 0.05), C4 by 11% (P < 0.05), IL-2 by 14% (P < 0.05), and serum iron values by 23% (P < 0.01), and decreased the diarrhea ratio (P < 0.05) relative to the control on d 30. Compared with the controls, supplementation with antibiotic increased ConA- and PHA-induced spleen lymphocyte proliferation (P < 0.05) on d 15, decreased the diarrhea ratio (P < 0.05), and increased the PHA-induced spleen lymphocyte proliferation (P < 0.05) and serum iron values (P < 0.01) on d 30. These results support the possible use LF as an immunostimulant to improve immune functions and strengthen host defenses and would seem to be a good method for defending weanling piglets from infections and weanling stress.

Oral lactoferrin results in T cell-dependent tumor inhibition of head and neck squamous cell carcinoma in vivo

PURPOSE

Human lactoferrin is a naturally occurring glycoprotein that inhibits cancer growth. Our purpose was to evaluate recombinant human lactoferrin as a chemotherapeutic agent against head and neck squamous cell carcinoma.

EXPERIMENTAL DESIGN

Controlled experiments both in vitro and in the murine model evaluating both the effect and mechanism of lactoferrin on cancer growth.

RESULTS

In both human and murine cell lines, lactoferrin induced dose-dependent growth inhibition. Using flow cytometric analysis, lactoferrin was shown to induce G(1)-G(0) growth arrest. This arrest seemed to be modulated by down-regulation of cyclin D1. In the in vitro model, luminex data revealed that lactoferrin inhibited cellular release of proinflammatory and prometastatic cytokines, including interleukin-8, interleukin-6, granulocyte macrophage colony-stimulating factor, and tumor necrosis factor-alpha. Lactoferrin up-regulated the cellular activation of nuclear factor-kappaB within 4 h of cellular exposure. In C3h/HeJ mice implanted with SCCVII tumors, orally delivered lactoferrin inhibited tumor growth by 75% compared with control mice. Immunohistochemical analysis of harvested tumors revealed up to 20-fold increases of lymphocytes within treated animals. When mice were depleted of CD3(+) cells, all lactoferrin-induced tumor inhibition was abrogated.

CONCLUSION

We conclude that human recombinant lactoferrin can inhibit the growth of head and neck squamous cell carcinoma via direct cellular inhibition as well as systemically via immunomodulation. Our data support the study of human lactoferrin as an immunomodulatory compound with therapeutic potential.

Anti-inflammatory potential of a malleable matrix composed of fermented whey proteins and lactic acid bacteria in an atopic dermatitis model

Background

Over the last 10 years, whey proteins have received considerable attention in the area of functional foods and nutraceuticals. In this paper, a novel fermented whey protein-based product described as a gel-like Malleable Protein Matrix (MPM) has been tested for its anti-inflammatory activity. Preliminary in vitro results have already indicated that MPM could exert such an anti-inflammatory activity.

Methods

The systemic anti-inflammatory activity of the MPM was explored using the oxazolone-induced atopic contact dermatitis mouse model (ACD). Parameters including ear thickness, side effects as well as neutrophil extravasation were monitored.

Results

In the ACD model, the MPM exhibited an anti-inflammatory effect comparable to that of hydrocortisone (positive control). Mice fed with MPM showed strong reduction of the ear inflammation while no side effects, as compared to hydrocortisone, were observed. The MPM seemed to reduce neutrophil extravasation in tissue as evidenced by blood polymorphonuclear cells and ear myeloperoxidase content.

Conclusion

The anti-inflammatory activity demonstrated in the ACD model suggests that the mechanism of action of the MPM is different than that of hydrocortisone and could become a relevant product for people suffering from dermatological manifestations associated with immune dysfunctions such as allergies, eczema, dermatitis, and autoimmune diseases.

Immunomodulation by a Malleable Matrix Composed of Fermented Whey Proteins and Lactic Acid Bacteria

Functional foods and nutraceuticals have gained in popularity over the last 10 years. Among natural health products, whey proteins and fermented milk products are paramount. A malleable protein matrix (MPM), composed of whey fermented by a lactic acid bacterium, capsular exopolysaccharides, vitamins, minerals, and peptides generated during the fermentation process, has the potential to be unique by combining multiple health-promoting components. Forced feeding experiments on healthy animals were performed to evaluate the immunomodulatory effect of MPM. Glutathione production, antibody response, and the modulation of leukocyte populations were monitored. The stimulation of the immune system by MPM consumption was evident as seen by the increased polymorphonuclear cell counts and intracellular glutathione levels. The absence of MPM-specific antibody production indicated a lack of undesirable immune recognition of MPM. The MPM, with its immunomodulatory properties, has the potential to be a food substitute or a functional food for maintenance of general immune health.

Candidate biomarkers for discrimination between infection and disease caused by Mycobacterium tuberculosis

Infection with Mycobacterium tuberculosis is controlled by an efficacious immune response in about 90% of infected individuals who do not develop disease. Although essential mediators of protection, e.g., interferon-gamma, have been identified, these factors are insufficient to predict the outcome of M. tuberculosis infection. As a first step to determine additional biomarkers, we compared gene expression profiles of peripheral blood mononuclear cells from tuberculosis patients and M. tuberculosis-infected healthy donors by microarray analysis. Differentially expressed candidate genes were predominantly derived from monocytes and comprised molecules involved in the antimicrobial defense, inflammation, chemotaxis, and intracellular trafficking. We verified differential expression for alpha-defensin 1, alpha-defensin 4, lactoferrin, Fcgamma receptor 1A (cluster of differentiation 64 [CD64]), bactericidal permeability-increasing protein, and formyl peptide receptor 1 by quantitative polymerase chain reaction analysis. Moreover, we identified increased protein expression of CD64 on monocytes from tuberculosis patients. Candidate biomarkers were then assessed for optimal study group discrimination. Using a linear discriminant analysis, a minimal group of genes comprising lactoferrin, CD64, and the Ras-associated GTPase 33A was sufficient for classification of (1) tuberculosis patients, (2) M. tuberculosis-infected healthy donors, and (3) noninfected healthy donors.

A double-blind, placebo-controlled, pilot study of bovine lactoferrin supplementation in bottle-fed infants

BACKGROUND

Lactoferrin has an array of biological activities that include growth, immune modulation, and antimicrobial effects. The aim of this randomized, placebo-controlled, double-blind study was to examine the impact of bovine lactoferrin supplementation in infants.

PATIENTS AND METHODS

Healthy, formula-fed infants, > or =34 weeks' gestation and < or =4 weeks of age, enrolled in a pediatric clinic. Infants received either formula supplemented with lactoferrin (850 mg/L) or commercial cow milk-based formula (102 mg/L) for 12 months. Growth parameters and information on gastrointestinal, respiratory, and colic illnesses were collected for the infants' first year. Antibodies to immunizations and hematologic parameters were measured at 9 and 12 months.

RESULTS

The lactoferrin-enhanced formula was well tolerated. There were significantly fewer lower respiratory tract illnesses, primarily wheezing, in the 26 lactoferrin-fed (0.15 episodes/y) compared with the 26 regular formula-fed (0.5 episodes/y) infants (P < 0.05). Significantly higher hematocrit levels at 9 months (37.1% vs 35.4%; P < 0.05) occurred in the lactoferrin-supplemented group compared with the control formula group.

CONCLUSIONS

Lactoferrin supplementation was associated with potentially beneficial outcomes such as significantly fewer lower respiratory tract illnesses and higher hematocrits. Larger, more focused studies in infants are warranted.

The struggle for iron: gastrointestinal microbes modulate the host immune response during infection

The gastrointestinal track is one source of potential bacterial entry into the host, and the local immune system at the mucosal border is paramount in establishing host immune tolerance and the immune response to invading organisms. Macrophages use iron for production of hydroxy-radical and superoxide reactions, which are necessary for microbial killing. Presumably, as a survival strategy, bacteria, which also require iron for survival, have adapted the ability to sequester iron from the host, thereby limiting the availability to macrophages. As current modes of antimicrobial therapy are evolving, examination of nontraditional therapies is emerging. One such potential therapy involves altering the bacterial micronutrient iron concentration. Necrotizing enterocolitis is a clinical condition where such a strategy makes intuitive sense. This review will describe the immune response to gastrointestinal infection, the mechanisms that the gastrointestinal system uses to absorb intraluminal iron, and the critical role iron plays in the infectious process.

Lactoferrin, a glycoprotein with immunomodulatory and mast cell stabilising properties, in skin of horses suffering from Culicoides hypersensitivity

Lactoferrin (LF), a glycogen of the transferrin family with anti-bacterial and immunomodulatory properties, is expressed in various secretions and tissues. Cutaneous LF serves as a mast cell stabilising compound, modulates T cell activity and is found during IgE-mediated late phase reactions at allergen challenged sites. Culicoides hypersensitivity (CHS) in horses is a common IgE-mediated allergic dermatitis, characterised by an early and late phase cutaneous reaction upon allergen challenge. The aim of the study presented here was to examine whether LF mRNA expression in skin biopsies from horses affected by CHS prior to and 4h following intradermal challenge with a commercial C. nubeculosus extract is modified in comparison to skin biopsies from non-affected horses. In order to obtain reliable data, real time PCR was performed and genes of interest were normalized using three different housekeeping genes, beta-actin, GAPDH, beta-2-microglobulin. In comparison to non-affected horses, higher variation in LF mRNA levels both prior to and post-intradermal challenge with C. nubeculosus extract was seen in horses affected by CHS. However, the statistical analysis demonstrated that LF mRNA expression was not significantly different between CHS affected and non-affected horses prior to intradermal challenge with C. nubeculosus extract. Intradermal injection of C. nubeculosus extract did not result in local upregulation of LF mRNA at 4h post-injection. LF mRNA expression was therefore not significantly different pre- or post-intradermal challenge with C. nubeculosus extract in either group. Our data indicate that clinically normal skin of horses affected by CHS is not characterized by modified maintenance levels of LF mRNA. In contrast to human skin allergen challenged sites, LF mRNA levels in horses affected by CHS are not significantly different to that of control sites at 4h post-injection of C. nubeculosus extract.

Bovine lactoferricin inhibits basic fibroblast growth factor- and vascular endothelial growth factor165-induced angiogenesis by competing for heparin-like binding sites on endothelial cells

Angiogenesis is a complex process whereby new blood vessels form from pre-existing vasculature in response to proangiogenic factors such as basic fibroblast growth factor (bFGF) and the 165-kd isoform of vascular endothelial growth factor (VEGF165). Angiogenesis inhibitors show considerable potential in the treatment of cancer because angiogenesis is necessary for tumor growth beyond a few millimeters in diameter because of the tumor's need for oxygen and nutrient supply, as well as waste removal. Bovine lactoferricin (LfcinB) is a peptide fragment of iron- and heparin-binding lactoferrin obtained from cow's milk. Here we provide in vivo and in vitro evidence that LfcinB has potent antiangiogenic activity. LfcinB strongly inhibited both bFGF- and VEGF165-induced angiogenesis in Matrigel plugs implanted in C57BL/6 mice. In addition, LfcinB inhibited the in vitro proliferation and migration of human umbilical vein endothelial cells (HUVECs) in response to bFGF or VEGF165 but was not cytotoxic to HUVECs. Rather, LfcinB complexed with heparin-like structures on the HUVEC surface that are involved in the binding of bFGF and VEGF165 to their respective receptors, thereby preventing receptor-stimulated angiogenesis. These findings suggest that LfcinB may have utility as an antiangiogenic agent for the treatment of human cancers.

Transgenic cows that produce recombinant human lactoferrin in milk are not protected from experimental Escherichia coli intramammary infection

This is the first study describing an experimental mastitis model using transgenic cows expressing recombinant human lactoferrin (rhLf) in their milk. The aim of the study was to investigate the concentrations in milk and protective effects of bovine and recombinant human lactoferrin in experimental Escherichia coli mastitis. Experimental intramammary infection was induced in one udder quarter of seven first-lactating rhLf-transgenic cows and six normal cows, using an E. coli strain isolated from cows with clinical mastitis and known to be susceptible to Lf in vitro. Clinical signs were recorded during the experimental period, concentrations of human and bovine Lf and indicators of inflammation and bacterial counts were determined for milk, and concentrations of acute-phase proteins and tumor necrosis factor alpha were determined for sera and milk. Serum cortisol and blood hematological and biochemical parameters were also determined. Expression levels of rhLf in the milk of transgenic cows remained constant throughout the experiment (mean, 2.9 mg/ml). The high Lf concentrations in the milk of transgenic cows did not protect them from intramammary infection. All cows became infected and developed clinical mastitis. The rhLf-transgenic cows showed milder systemic signs and lower serum cortisol and haptoglobin concentrations than did controls. This may be explained by lipopolysaccharide-neutralizing and immunomodulatory effects of the high Lf concentrations in their milk. However, Lf does not seem to be a very efficient protein for genetic engineering to enhance the mastitis resistance of dairy cows.

Human and bovine lactoferrins in the milk of recombinant human lactoferrin-transgenic dairy cows during lactation

Seven Friesian human lactoferrin (hLf)-transgenic primiparous dairy cows expressing recombinant hLf (rhLf) in their milk were included in the study. After calving, concentrations of rhLf and bovine LF (bLf) in the milk, somatic cell count and milk yield were determined. The concentration of rhLf was found to be constant, about 2.9 mg/mL, throughout the early lactation period of 3 months. The concentration of bLf in colostrum was higher after calving, but decreased rapidly during the first days of lactation. The mean concentration of bLf was 0.15 mg/mL, but concentrations varied between cows from 0.07 mg/mL to 0.26 mg/mL. Based on that, it may be possible to improve the non-specific host defence mechanism in the mammary gland of dairy cows by enhancing the content of rhLf in the milk.

Safety and efficacy of a milk-derived extract in the treatment of plaque psoriasis: an open-label study

BACKGROUND

XP-828L is a nutraceutical compound obtained by the extraction of a growth factors-enriched protein fraction from bovine milk. XP-828L may improve psoriasis.

OBJECTIVES

An open-label study was performed to determine the efficacy, tolerability and safety of XP-828L in the treatment of plaque psoriasis.

METHODS

Eleven adult patients with chronic, stable plaque psoriasis on 2% or more of body surface area (BSA) received 5 g of oral XP-828L twice daily for 56 days.

RESULTS

All 11 patients completed the 56 days of treatment. At day 28, 6 of the 11 patients showed a reduction in PASI score. At 56 days, seven subjects had a decrease in PASI score ranging from 9.5% to 81.3%. Eight (8) out of 11 patients agreed to participate in an additional 8-week extension treatment phase. Improvement of psoriasis was maintained during the extension period. No clinically significant adverse events or laboratory abnormalities occurred.

CONCLUSION

XP-828L may improve psoriasis in patients with mild-to-moderate psoriasis.

Characterization of lactoferrin receptor in brain endothelial capillary cells and mouse brain

We present, herein, the evidence for lactoferrin (Lf) binding sites in brain endothelial capillary cells (BCECs) and mouse brain. The results from confocal microscopy showed the presence of Lf receptors on the surface of BCECs and the receptor-mediated endocytosis for Lf to enter the cells. Saturation binding analyses revealed that Lf receptors exhibited two classes of binding sites in BCECs (high affinity: dissociation constant (K (d)) = 6.77 nM, binding site density (B (max)) = 10.3 fmol bound/mug protein; low affinity: K (d) = 4815 nM, B (max) = 1190 fmol bound/mug protein) and membrane preparations of mouse brain (high affinity: K (d) = 10.61 nM, B (max) = 410 fmol bound/mug protein; low affinity: K (d) = 2228 nM, B (max) = 51641 fmol bound/mug protein). The distribution study indicated the effective uptake of (125)I-Lf in brain after intravenous administration. The present study provides experimental evidence for the application of Lf as a novel ligand for brain targeting.

Mucosal innate immune factors in the female genital tract are associated with vaginal HIV-1 shedding independent of plasma viral load

Recent studies indicate that mucosal innate immune factors modulate HIV-1 infection in vitro. Our interest was to examine the levels of innate mucosal factors for their potential association with HIV-1 shedding in the female genital tract. Vaginal lavages were collected from HIV-1-infected women who had vaginal viral loads (VVL) that were below, within, or above the 90% confidence interval (CI) predicted by their matched plasma viral loads. Innate immune factors [cathepsin D, lactoferrin (Lf), myeloid related protein (MRP)-8, MRP-8/14, secretory leukocyte protease inhibitor, and gp340], cytokines (IL-1beta and TNF-alpha), and chemokines (MIP-1alpha, MIP-1beta, RANTES, and SDF-1alpha) were quantified by ELISA. Leukocyte levels were determined using a leukocyte reagent strip for urinalysis. Lf, MRP-8/14, gp340, and IL-1beta levels were significantly higher in vaginal lavages above the 90% CI and generally correlated with each other and with VVL. Leukocyte levels were significantly higher in the lavages that had virus shedding above the 90% CI and correlated strongly with Lf levels and VVL. In this group of women, these results suggest that the levels of certain innate immune factors are more closely associated with HIV-1 shedding in the genital mucosa than plasma virus concentrations.

Human lactoferrin upregulates expression of KDR/Flk-1 and stimulates VEGF-A-mediated endothelial cell proliferation and migration

Lactoferrin (LF) is a multifunctional iron-binding glycoprotein, which plays a variety of biological processes including immunity. In this study, we demonstrate that human LF upregulates KDR/Flk-1 mRNA and protein levels in HUVECs at an optimal concentration of 5 microg/ml, which subsequently promotes the VEGF-induced proliferation and migration of the endothelial cells. Exposure of HUVECs to LF significantly increased VEGF-induced ERK MAP kinase phosphorylation. The maximal stimulation of KDR/Flk-1 expression by LF was correlated with LF-induced increase in cell proliferation and migration. These findings suggest that LF may stimulate in vivo angiogenesis via upregulation of KDR/Flk-1 expression in endothelial cells.