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PubMed1988

Lactoferrin in aspirates of odontogenic cyst fluid.

The possibility that the presence of lactoferrin in aspirates of odontogenic cyst fluid might be a useful preoperative diagnostic marker for odontogenic keratocyst was investigated. Using qualitative and quantitative immunodiffusion methods fluid from 29 of 29 dental (radicular) cysts, 12 of 14 dentigerous cysts and 27 of 31 keratocysts were found to contain lactoferrin. Although some of the highest concentrations of lactoferrin were detected in fluids from keratocysts, there was no significant difference between lactoferrin concentrations among the three groups. Neutrophil elastase was detected in 20 of 24 samples tested, 22 of which also contained lactoferrin. Immunocytochemical localisation of both lactoferrin and elastase was confined to neutrophils infiltrating cyst walls. These results suggest that lactoferrin in fluid from odontogenic cysts is derived from infiltrating neutrophils and that its presence in aspirated fluids is not a useful diagnostic marker for odontogenic keratocyst.

Biomarkers↗

PubMed1989

Quantitation of lactoferrin in odontogenic cyst fluids.

A competitive enzyme linked immunosorbent assay (ELISA) method was used to measure the concentration of lactoferrin in fluids from 36 odontogenic keratocysts, 15 dentigerous cysts, and 30 radicular/residual cysts. Keratocyst fluids contained significantly higher concentrations of lactoferrin than fluids from the other two types of cyst (p less than 0.001); but the range of values obtained within each group was large. Although lactoferrin represents a larger proportion of the total protein in keratocyst fluids than in dentigerous or radicular cyst fluids, lactoferrin concentration is not an absolute diagnostic marker for keratocysts. Lactoferrin concentration correlated strongly with the numbers of neutrophils present in keratocyst fluids (p less than 0.001), less so for dentigerous cyst fluids (p less than 0.05, and not at all in the case of radicular cyst fluids. It is suggested that neutrophils are the source of lactoferrin in the three categories of cyst studied but that the relatively impermeable nature of the keratocyst lining probably accounts for the particularly high concentrations of lactoferrin found in their fluids. Given that most keratocysts were asymptomatic, acute inflammation itself does not explain the reason for the high numbers of neutrophils in many of the fluids.

Dentigerous Cyst↗

PubMed1988

Affinities of Treponema pallidum for human lactoferrin and transferrin.

The acquisition of lactoferrin and transferrin by live Treponema pallidum organisms was examined. Saturation binding kinetics were obtained for virulent treponemes with increasing amounts of radioiodinated lactoferrin but not with transferrin. Furthermore, lactoferrin bound up to 100 times more effectively than transferrin. Only unlabelled lactoferrin stoichiometrically completed with iodinated lactoferrin binding. Time course kinetics showed maximum lactoferrin acquisition within the first five minutes at 34 degrees C. Optimum iron accumulation, however, was achieved by T pallidum in 30 minutes at 34 degrees C, and amounts of iron were six times greater than the equivalent amount of lactoferrin bound. Interestingly, iron uptake was also detected in the presence of transferrin, despite the minimal amounts of transferrin acquired by live treponemes. These observations reinforce the possibility that the associations of T pallidum with host molecules, such as plasma proteins, are essential for survival of the parasite within host environments.

Humans↗

PubMed2006

Perspectives on interactions between lactoferrin and bacteria.

Lactoferrin has long been recognized for its antimicrobial properties, initially attributed primarily to iron sequestration. It has since become apparent that interaction between the host and bacteria is modulated by a complex series of interactions between lactoferrin and bacteria, lactoferrin and bacterial products, and lactoferrin and host cells. The primary focus of this review is the interaction between lactoferrin and bacteria, but interactions with the lactoferrin-derived cationic peptide lactoferricin will also be discussed. We will summarize what is currently known about the interaction between lactoferrin (or lactoferricin) and surface or secreted bacterial components, comment on the potential physiological relevance of the findings, and identify key questions that remain unanswered.

Animals↗

PubMed1987

Luminal digestion of lactoferrin in suckling and weanling rats.

The development of luminal digestion of lactoferrin was evaluated in vitro by incubating 125I-labeled lactoferrin with fluid flushed from the stomach and small intestine of 12-day-old suckling and 31-day-old weanling rats, followed by measurement of radioactivity in trichloroacetic acid-soluble material. Gastric hydrolysis of lactoferrin at pH 3.2 in the weanling was 20-fold greater than that in the suckling. In the small intestine at neutral pH, luminal degradation of lactoferrin was minimal in the suckling but increased significantly after weaning, with maximal degradative capacity demonstrable in the midjejunum. Sephadex G-75 chromatography of intestinal acid-soluble breakdown products revealed two peaks of radioactivity, each comprising 40-45% of the total product; analysis of intestinal acid-precipitable products by polyacrylamide gel electrophoresis yielded several discrete lower molecular weight species. Food deprivation for 12 h/100 g body wt decreased lactoferrin degradation in the weanling jejunum and midjejunum. Our findings suggest that lactoferrin digestion may vary with respect to postnatal age of the organism, segment of the gastrointestinal tract, and dietary state. In the young animal, lactoferrin degradation is minimal, and consequently its potential for biological function may be high.

Acids↗

PubMed1998

Metal-dependent expression of ferritin and lactoferrin by respiratory epithelial cells.

Increased availability of catalytically active metal has been associated with an oxidative injury. The sequestration of transition metals within intracellular ferritin confers an antioxidant function to this protein. Such storage by ferritin requires that the metal be transported across a cell membrane. We tested the hypothesis that, in response to in vitro exposures to catalytically active metal, respiratory epithelial cells increase the production of lactoferrin and ferritin to bind, transport, and store this metal with their coordination sites fully complexed. Residual oil fly ash is an emission source air pollution particle with biological effects that, both in vitro and in vivo, correspond with its metal content. Cell cultures were exposed to 0-200 micrograms/ml of oil fly ash for 2 and 24 h. Concentrations of ferritin and lactoferrin mRNA were estimated by reverse transcription-polymerase chain reaction, and concentrations of ferritin and lactoferrin proteins were measured in parallel. mRNA for ferritin did not change with exposure to oil fly ash. However, ferritin protein concentrations increased. Although mRNA for transferrin receptor decreased, mRNA for lactoferrin increased after incubation with the particle. Similar to changes in mRNA, transferrin concentration decreased, whereas that of lactoferrin increased. Deferoxamine, a metal chelator, inhibited these responses, and exposure of the cells to vanadium compounds alone reproduced elevations in lactoferrin mRNA. We conclude that increases in ferritin and lactoferrin expression can be metal dependent. This response can function to diminish the oxidative stress a metal chelate presents to a living system.

Air Pollutants↗

PubMed1999

Respiratory epithelial cells demonstrate lactoferrin receptors that increase after metal exposure.

Human airway epithelial cells can increase expression of both lactoferrin and ferritin after exposure to catalytically active metal. These proteins transport and store metal, with coordination sites fully complexed, and therefore can diminish the oxidative stress. The intracellular transport of lactoferrin results in a transfer of complexed metal to ferritin, where it is stored in a less reactive form. This effort to control the injurious properties of metals would be facilitated by lactoferrin receptors (LfRs) on airway epithelial cells. We tested the hypotheses that 1) LfRs exist on respiratory epithelial cells and 2) exposure to both an air pollution particle, which has abundant concentrations of metals, and individual metal salts increase the expression of LfRs. Before exposure to either the particle or metals, incubation of BEAS-2B cells with varying concentrations of 125I-labeled lactoferrin demonstrated lactoferrin binding that was saturable. Measurement of 125I-lactoferrin binding after the inclusion of 100 micrograms/ml of oil fly ash in the incubation medium demonstrated increased binding within 5 min of exposure, which reached a maximal value at 45 min. Inclusion of 1.0 mM deferoxamine in the incubation of BEAS-2B cells with 100 micrograms/ml of oil fly ash decreased lactoferrin binding. Comparable to the particle, exposure of BEAS-2B cells to either 1.0 mM vanadyl sulfate or 1.0 mM iron (III) sulfate, but not to nickel sulfate, for 45 min elevated LfR activity. We conclude that LfRs on respiratory epithelial cells increased after exposure to metal. LfRs could participate in decreasing the oxidative stress presented to the lower respiratory tract by complexing catalytically active metals.

Air Pollution↗

PubMed1987

Lactoferrin in acute necrotizing pancreatitis.

Lactoferrin, as measured in the pancreatic juice, has been thought to be of diagnostic value in chronic pancreatitis, but due to the hazards in cannulation of the pancreatic duct in the acute phase of pancreatitis the behavior of lactoferrin has remained obscure. In this study, lactoferrin levels were studied in pancreas tissue specimens obtained in ablative surgery for acute necrotizing pancreatitis (ANP) and in serum samples. A higher pancreatic lactoferrin content was found in ANP than in normal pancreas. Lactoferrin seemed not to leak from a necrotic pancreas in any considerable amounts into the circulation, as no differences were found in serum lactoferrin concentrations between ANP and controls. It remains an open question whether the lactoferrin increase is only an unspecific reaction in inflammation or is something specific for pancreatitis.

Acute Disease↗

PubMedDate not supplied

Lactoferrin in thyroid lesions: immunoreactivity in fine needle aspiration biopsy samples.

OBJECTIVE: Lactoferrin is an iron-binding protein that has been used for distinguishing normal from neoplastic conditions in many different tissues. In order to improve evaluation of thyroid lesions, we studied the lactoferrin immunoreaction in cytologic smears obtained by fine needle aspiration and in biopsy samples from primary neoplasms and from adenomatous goiter. STUDY DESIGN: A retrospective study on fine needle aspiration cytology samples and corresponding available biopsies from thyroid lesions in patients examined at São Paulo County Hospital between 1982 and 1992, performed in order to evaluate lactoferrin immunoreactivity in morphologically well characterized samples from neoplastic and nonneoplastic lesions. Immunoperoxidase procedures were performed using monospecific polyclonal rabbit antihuman lactoferrin as a primary antibody and biotinylated goat antirabbit IgG as a secondary antibody. Amplification was performed with the avidin-biotin-peroxidase complex, and the color sign of the positive reactions was developed using a diaminobenzidine solution. RESULTS: Lactoferrin was not detected in cytologic smears from goiters, whereas only one biopsy was slightly positive (1/21, or 4.76%). One smear from adenoma showed low positive staining (1/19, or 5.26%), which was present in 4 of 13 biopsies (30.77%) from adenoma. Papillary carcinomas were positive in 19 of 33 smears (57.58%) and in 100% of biopsies, whereas 31.25% (5/16) of follicular carcinoma smears were positive for lactoferrin, detected in all the biopsy samples. CONCLUSION: Lactoferrin immunoreactivity was strongly associated with neoplastic proliferation and may be used as a useful auxiliary marker to distinguish malignant from benign thyroid lesions in cytologic smears and biopsy samples.

Adenoma↗

PubMed1994

Lactoferrin binding to heparan sulfate proteoglycans and the LDL receptor-related protein. Further evidence supporting the importance of direct binding of remnant lipoproteins to HSPG.

Bovine lactoferrin inhibits the clearance of remnant lipoproteins from the plasma and competes with the cell-surface binding of apolipoprotein (apo) E-enriched remnants. We established that lactoferrin inhibits remnant binding and uptake by interacting with both heparan sulfate proteoglycans (HSPG) and the low-density lipoprotein receptor-related protein (LRP). The binding of 125I-lactoferrin was inhibited 45% to 60% in HepG2 hepatocytes and wild-type Chinese hamster ovary (CHO) cells treated with heparinase to remove HSPG. In mutant CHO cells (pgsD-677) lacking HSPG, the level of 125I-lactoferrin binding was approximately 50% that seen with wild-type CHO cells; thus, about one half of lactoferrin binding appears to be mediated through cell-surface HSPG. A significant fraction of the residual binding of the lactoferrin appears to be mediated through the LRP. The 39-kd protein known to bind to the LRP and to block ligand interaction inhibited 125I-lactoferrin degradation in wild-type CHO cells by 60% to 65%. The addition of the 39-kd protein plus heparinase treatment reduced the binding by 85% to 90% (this combination blocks direct interaction with both the LRP and HSPG). However, it was also shown that the 39-kd protein bound to HSPG and the LRP. Heparinase treatment of wild-type CHO cells decreased the binding of the 125I-39-kd protein by approximately 40%, and the mutant CHO cells lacking HSPG bound half as much 125I-39-kd protein as wild-type CHO cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2003

Evaluation of lysozyme and lactoferrin in lacrimal and other ocular glands of bison and cattle and in tears of bison.

OBJECTIVE: To evaluate lactoferrin and lysozyme content in various ocular glands of bison and cattle and in tears of bison. SAMPLE POPULATION: Tissues of ocular glands obtained from 15 bison and 15 cattle and tears collected from 38 bison. PROCEDURE: Immunohistochemical analysis was used to detect lysozyme and lactoferrin in formalin-fixed, paraffin-embedded sections of the ocular glands. Protein gel electrophoresis was used to analyze ocular glands and pooled bison tears by use of a tris-glycine gel and SDS-PAGE. Western blotting was used to detect lactoferrin and lysozyme. RESULTS: Immunohistochemical staining for lactoferrin was evident in the lacrimal gland and gland of the third eyelid in cattle and bison and the deep gland of the third eyelid (Harder's gland) in cattle. Equivocal staining for lactoferrin was seen for the Harder's gland in bison. An 80-kd band (lactoferrin) was detected via electrophoresis and western blots in the lacrimal gland and gland of the third eyelid in cattle and bison, Harder's glands of cattle, and bison tears. An inconsistent band was seen in Harder's glands of bison. Lysozyme was not detected in the lacrimal gland of cattle or bison with the use of immunohistochemical analysis or western blots. Western blots of bison tears did not reveal lysozyme. CONCLUSIONS AND CLINICAL RELEVANCE: Distribution of lactoferrin and a lack of lysozyme are similar in the lacrimal gland of cattle and bison. Differences in other tear components may be responsible for variability in the susceptibility to infectious corneal diseases that exists between bison and cattle.

Animals↗

PubMed2000

Presence of a glycan at a potential N-glycosylation site, Asn-281, of bovine lactoferrin.

This work was performed to clarify the differences in glycan moieties between multiple molecular mass forms of bovine lactoferrins (bovine lactoferrins-a and -b). After digestion of both bovine lactoferrins with cyanogen bromide and V8 protease, glycopeptides were successively purified by concavalin A affinity chromatography and HPLC on an octadecylsilyl column. Four glycopeptides glycosylated at Asn-233, -368, -476, and -545 were obtained from both hydrolysates of bovine lactoferrins-a and -b. On the other hand, a glycopeptide glycosylated at Asn-281 was only detected in hydrolysate of bovine lactoferrin-a, indicating that bovine lactoferrin-a possessed five N-glycosylated sites. The glycan linked to Asn-281 of bovine lactoferrin-a was found to consist of fucose, galactose, and N-acetylgalactosamine in addition to mannose and N-acetylglucosamine. HPLC analysis of this glycan on a normal phase column showed that peaks of several glycans were detected. These glycans changed to one major glycan consisting of only mannose and N-acetylglucosamine on exoglycosidase digestion. From these results, this glycan seemed to be of the complex type and possess heterogeneous structure.

Acetylgalactosamine↗

PubMed1990

Comparison of lactoferrin content in colostrum between different cattle breeds.

Lactoferrin content of colostrum obtained from cows within 24 h after parturition was measured using a single radial immunodiffusion test and was compared among cows of two dairy breeds (Holstein-Friesian, Jersey) and two beef breeds (Japanese Black and Japanese Brown). Average lactoferrin content in colostrum of dairy breeds was 2 mg/ml and in colostrum of beef breeds was .5 mg/ml. Lactoferrin content of colostrum due to lactation number was also different among breeds. In dairy breeds, multiparous cows had lactoferrin content two to three times higher than that of primiparous cows; beef breeds showed no obvious differences between lactation years. Lactoferrin content also varied considerably within breed. In beef breeds, half the cows had values of nearly zero. Transferrin content in colostrum was fairly constant (.9 mg/ml) and was not as variable among and within breeds. There was no correlation between lactoferrin and transferrin contents in colostrum. Examination of cows lacking lactoferrin suggested that transferrin plays an important role as an iron carrier from a cow to her newborn calf.

Animals↗

PubMed1991

Potent antibacterial peptides generated by pepsin digestion of bovine lactoferrin.

The antibacterial properties of enzymatic hydrolysates of bovine lactoferrin were examined to determine whether active peptides are produced from this protein. Hydrolysates prepared by cleavage of lactoferrin with porcine pepsin, cod pepsin, or acid protease from Penicillium duponti showed strong activity against Escherichia coli O111, whereas hydrolysates produced by trypsin, papain, or other neutral proteases were much less active. Low molecular weight peptides generated by porcine pepsin cleavage of lactoferrin showed broad-spectrum antibacterial activity, inhibiting the growth of a number of Gram-negative and Gram-positive species, including strains that were resistant to native lactoferrin. The antibacterial potency of the hydrolysate was at least eightfold greater than that of undigested lactoferrin with all strains tested. The active peptides retained their activity in the presence of added iron, unlike native lactoferrin. The effect of the hydrolysate was bactericidal as indicated by a rapid loss of viability of E. coli O111. The lactoferrin hydrolysate described in the present study has commercial value as a natural preservative agent for use in foods and cosmetics, and as a functional component of new clinical foods for prevention or treatment of gastrointestinal disease.

Animals↗

PubMed1993

Separation and characterization of the C-terminal half molecule of bovine lactoferrin.

The C-terminal half molecule (C lobe) of bovine lactoferrin was isolated by mild tryptic hydrolysis of lactoferrin followed by gel filtration and ion-exchange chromatography. The identity of the fragment was established by determining its N-terminal and C-terminal amino acid sequences and comparing them with the amino acid sequence of intact lactoferrin. The isoelectric point of the C lobe ranged between pH 6.2 and 6.5 as measured by isoelectric focusing on polyacrylamide gels. The circular dichroic spectrum in the range of 250 to 350 nm of the C lobe differed slightly from that of intact lactoferrin. The pattern of lectin reactivity was similar for both the C lobe and intact lactoferrin. The C lobe showed partial antigenic identity with intact lactoferrin as demonstrated by the double immunodiffusion method, and pH dependence of iron binding of C lobe is the same as that of intact lactoferrin molecule.

Amino Acid Sequence↗

PubMed2000

Antimicrobial properties of pepsin-digested lactoferrin added to carrot juice and filtrates of carrot juice.

The objective of this study was to determine the antimicrobial activity of pepsin-digested lactoferrin added to carrot juice and filtrates prepared from carrot juice. Lactoferrin isolated from raw skim milk was digested by pepsin for 4 h at pH 3. The digest of lactoferrin was lyophilized, and the antimicrobial activity of the digests was determined in peptone-yeast-glucose broth, carrot juice, permeate from carrot juice, and the dialysate of carrot juice permeate using Escherichia coli (American Type Culture Collection strain 35343) as the test organism. Growth of E. coli and the inhibitory effect of the peptide were greater in peptone-yeast-glucose broth at pH 7 than at pH 4. The peptic digest of lactoferrin did not have antimicrobial properties in carrot juice at concentrations of less than 10 mg/ml of juice. Carrot juice was filtered through a membrane with a molecular weight rejection of 10,000 or 500 Da, and the permeate was dialyzed against distilled water. Growth of E. coli was delayed in the filtrate by 5 mg but not by 1 mg of the peptic digest of lactoferrin per ml of filtrate. Bacterial counts of the control and experimental samples were not significantly different after 24 h of incubation. The peptic digest of lactoferrin at a concentration of 5 mg of digest per ml of dialysate was bacteriostatic toward E. coli after 24 h of incubation at 23 degrees C. Dialysis of permeate caused a percentage reduction in cation concentration in the permeate ranging from 69.23% (Co) to 99.32% (Na). The antimicrobial activity of lactoferrin added to carrot juice was probably inhibited by cations.

Animals↗

PubMed2000

Lactoferrin binding to the rat asialoglycoprotein receptor requires the receptor's lectin properties.

Lactoferrin binds to rat hepatic lectin 1 (RHL1), the major subunit of the asialoglycoprotein (ASGP) receptor, with high affinity, by a galactose-independent mechanism. To better understand the molecular basis of this novel interaction, we compared the binding of lactoferrin and asialo-orosomucoid (ASOR) to isolated rat hepatocytes and to purified ASGP receptors as a function of pH, Ca(2+) and receptor acylation. Binding of (125)I-lactoferrin and (125)I-ASOR to isolated rat hepatocytes at 4 degrees C decreased sharply at pH<6, following similar titration curves. Binding of (125)I-lactoferrin and (125)I-ASOR to hepatocytes was Ca(2+)-dependent. Binding increased progressively at > or =300 microM CaCl(2), in the presence of 1 mM EDTA. Monensin treatment of hepatocytes, which causes hepatocytes to accumulate inactive ASGP receptors, reduced surface binding of (125)I-lactoferrin and (125)I-ASOR by 46 and 49%, respectively, with only a 16% loss of immunodetectable receptor protein from the cell surface. Finally, deacylation of purified ASGP receptors in vitro with 1 M hydroxylamine abolished receptor lectin activity as reflected by the loss of (125)I-ASOR binding as well as the complete loss of specific (125)I-lactoferrin binding. Treatment with 1 M Tris had no effect on binding of either ligand. We conclude from these data that galactose-independent lactoferrin binding to the ASGP receptor requires the receptor's carbohydrate-recognition domain to be in an active configuration. An active configuration is promoted by neutral pH and Ca(2+), and also requires the receptor subunits to be acylated.

Animals↗

PubMed2000

Lactoferrin upregulates the expression of CD4 antigen through the stimulation of the mitogen-activated protein kinase in the human lymphoblastic T Jurkat cell line.

The main biological properties of lactoferrin are thought to concern inflammation and immunomodulation processes, including maturation of immature B and T cells. Lactoferrin accelerates T-cell maturation by inducing the expression of the CD4 surface marker. In this report, using the Jurkat T-cell line, we have shown that lactoferrin upregulates the expression of CD4 antigen through the activation of a transduction pathway. Using an anti-phosphotyrosine antibody, lactoferrin was demonstrated to induce a cascade of phosphorylation of numerous proteins on their tyrosine residues. This tyrosine-phosphorylation was transient, reaching maxima between 5 and 10 min. We also identified the mitogen-activated protein kinase (MAP kinase) which presented an enhanced catalytic activity, reaching a maximum at 10 min of incubation with lactoferrin. Moreover, the use of inhibitors such as genistein and PD98059, tyrosine kinases and MAP kinase kinase (or MEK) inhibitors respectively, allowed us to correlate the activation of MAP kinase with the upregulation of CD4 expression. Finally, using Lck-defective Jurkat cells, our results showed that the p56(lck) (Lck) kinase is necessary for MAP kinase activity and CD4 expression. This paper demonstrates that lactoferrin activates transduction pathway(s) in lymphoblastic T-cells, and that Lck and the Erk2 isoform of MAP kinase are implicated in the upregulation of CD4, induced by lactoferrin in these cells.

CD4 Antigens↗