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PubMed1990

Release of lactoferrin and elastase in human allergic skin reactions.

Our previous skin chamber studies have shown prominent accumulation of viable neutrophils in human allergic skin reaction sites. To determine whether such neutrophils release components that may be pathogenic in allergic reactions, we have compared the patterns of release of five components: 1) lactoferrin, present in specific granules; 2) and 3) elastase and myeloperoxidase, present mainly in azurophilic granules; 4) lactic dehydrogenase, a cytosolic component generally released during cell damage; 5) histamine, present in mast cells and basophils but not in neutrophils. In 13 pollen-sensitive subjects we found that continuous antigen challenge for 5 h lead to a peak of histamine release into overlying skin chambers during the 1st h, followed by a plateau of low level histamine release over the succeeding 4 h. In contrast, there was no significantly increased released of lactoferrin or elastase during the first h, but significantly increased accumulation of these components at Ag challenge sites over the next 4 h. There was no significant difference at Ag vs buffer control sites in the levels of either myeloperoxidase or lactic dehydrogenase. The increased levels of lactoferrin and elastase at antigen challenge sites in the 2nd to 5th h were not simply a reflection of the greater numbers of neutrophils present in such sites because the levels of these components did not correlate significantly with the number of neutrophils in chamber fluids obtained from individual sites. However, such lactoferrin levels did correlate significantly with the amount of histamine released earlier during the 1st h of Ag challenge at individual sites. These findings suggest a selective in vivo release of neutrophil components in IgE-mediated human allergic skin reactions, possibly related in degree to earlier mast cell activation. Inasmuch as lactoferrin likely plays a role in reactive oxidants effects and elastase is a potent nonspecific protease, release of these agents could play a pathogenic role in late phase allergic reactions.

Adult↗

PubMed2006

[Identification of low-molecular weight prostate-specific antigen(PSA) and lactoferrin in the prostatic secretion of benign prostatic hyperplasia].

OBJECTIVE: To investigate the expression of low-molecular-weight PSA(lw-PSA) and lactoferrin in the expressed prostatic secretion (EPS) from both benign prostatic hyperplasia (BPH) and normal prostate. METHODS: Forty human EPS samples obtained from 20 BPH patients and 20 normal males were subjected to two-dimensional gel electrophoresis (2-DE). Mass spectrometry was performed to confirm the nature of the secreted proteins in EPS. RESULTS: One uniquely expressed protein in BPH was detected and mass spectrometry determined its nature as lw-PSA (molecular weight 10x10(3), pI 8.5-9.3). More importantly, Western blotting analysis also revealed that lw-PSA detected in BPH-EPS, but was undetectable in BPH-free EPS. In addition, up-regulation of Lactoferrin (molecular weight 35x10(3), pI 7-7.5) in BPH-EPS, as compared with BPH-free EPS, was also observed. More interestingly, lactoferrin was absent in prostate cancer tissues. CONCLUSION: Our results indicate lw-PSA may be produced specifically by BPH epithelium and it has a potential to be used as a specific biological marker for the diagnosis of BPH. In addition, benign prostatic epithelium can produce more lactoferrin while prostate cancer tissues go without its lactoferrin secretion.

Aged↗

PubMed1991

Lactoferrin in rheumatoid arthritis and systemic lupus erythematous.

Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are prototypes of autoimmune diseases. In order to assess the inflammatory status in these conditions, lactoferrin, stored in specific granules of neutrophils, was measured in serum samples of patients with SLE and RA. In RA, the mean serum lactoferrin level (1221.397 +/- 289.476 ng/ml) was significantly higher than that in normal individuals (753.364 +/- 124.063 ng/ml). Surprisingly, there were no significant differences between active SLE (672.682 +/- 356.154 mg/ml) and inactive SLE (642.267 +/- 270.456 ng/ml). Still, no differences were found between normal volunteers, active SLE and inactive SLE. Serum lactoferrin in SLE correlated significantly with CRP (Rs = 0.4089, p less than 0.01), but not with complement level and ANA titers. Thus in RA serum lactoferrin was highly elevated and this indicated that PMN in systemic circulation was activated. In SLE the correlation of CRP with lactoferrin reflected the role of later protein in inflammation.

Adolescent↗

PubMed1977

The association of Ga-67 and lactoferrin.

Activity was seen in the breasts of a patient with galactorrhea 72 h after intravenous injection of Ga-67 citrate. Differential protein separation of breast secretion, extracted from the breast, revealed that the Ga-67 was contained primarily in the lactoferrin-rich protein fraction. Additional studies on partially purified lactoferrin revealed that lactoferrin binds Ga-67 more avidly than does transferrin. Since lactoferrin is present in high concentration non only in human colostrum and milk, but also in neutrophilic leukocytes, bone marrow, spleen, colon, tears, and in genital, salivary, and nasopharyngeal secretions, binding of Ga-67 to lactoferrin may explain the localization of Ga-67 in certain normal tissues and inflammatory lesions.

Adult↗

PubMed1987

Lactoferrin uptake and iron processing into macrophages: a study in familial haemochromatosis.

Various properties of lactoferrin from neutrophils of normal individuals and patients with familial haemochromatosis were compared. No difference was found with respect to (1) the lactoferrin content of neutrophils, the molecular weight and isoelectric point of the protein, the dissociation of its complex with iron at acidic pH, its binding to isolated monocytes, and its uptake by the mouse reticulo-endothelial system. Macrophages from patients and controls were also found to be similar in their ability to bind and ingest lactoferrin and to process the iron provided by the protein. Therefore a defect in the interaction of lactoferrin with the reticulo-endothelial system, related either to the protein itself or to the cells, seems unlikely. A comparison of the lactoferrin- and the transferrin-mediated iron processing by monocytes is finally presented.

Adult↗

PubMed1982

Lactoferrin and transferrin in bovine milk in relation to certain physiological and pathological factors.

Mean transferrin and lactoferrin concentrations in whey samples from 376 uninfected quarters of 42 Holstein X Friesian cows on the 30th, 150th and 270th days of lactation were respectively 0.030 and 0.080 mg/ml. The mean transferrin concentration in serum was 4.63 mg/ml. Lactation number and location of quarters did not influence milk lactoferrin and transferrin values. Lactoferrin concentration increased significantly (P less than 0.01) in uninfected quarters from 0.03 to 0.06 and to 0.15 mg/ml on the three successive sampling times. Transferrin whey concentration increased significantly (P less than 0.01) only in late lactation, from 0.025 (30th and 150th days of lactation) to 0.035 mg/ml (270th day of lactation). Lactoferrin concentration increased significantly (P less than 0.01) in quarters infected by major pathogens (41 samples) whereas minor pathogen infections (61 samples) caused no significant increase. The correlation coefficients between milk lactoferrin and transferrin concentrations and somatic cell-count were 0.42 and 0.65 respectively.

Age Factors↗

PubMed1995

In vivo and in vitro effects of lactoferrin on Yersinia pseudotuberculosis.

Iron is a growth requirement for virtually all microbes. In the human body, extracellular iron is sequestered from microbes by binding to proteins such as lactoferrin. In this study the effect of lactoferrin and human milk on Yersinia pseudotuberculosis was investigated. Its growth in vitro was inhibited by iron-free, but not iron saturated, pure lactoferrin or human milk. Iron-free human milk and to a less extent normal human milk were bactericidal for Y. pseudotuberculosis cells that were suspended in deionized water. The in vivo studies also show that iron-saturated lactoferrin enhanced growth, whereas, the viable count was reduced by iron-free pure lactoferrin and EDDA. Nine envelope proteins were decreased or disappeared upon growth in iron-deficient medium, whereas one new high molecular weight protein appeared under the same conditions.

Animals↗

PubMed1995

Human lactoferrin induces phenotypic and functional changes in murine splenic B cells.

The immunotropic activities of human lactoferrin were studied with respect to phenotypic and functional changes in murine splenic B cells. Phenotypic changes were induced by human lactoferrin in splenic B-cell fractions separated by buoyant density. B cells from 7-8-day-old BALB/c mice isolated from a 50/60% Percoll gradient, gained characteristic features of more mature B cells manifested by an increase of surface IgD and complement receptor expression. Incubation of the analogous B-cell fraction from adult mice with human lactoferrin resulted in minor changes in relation to IgM and IgD expression. Besides induction of phenotypic changes on immature B cells, human lactoferrin enabled B cells from normal newborn and adult immunodeficient CBA/N mice to present antigen to an antigen-specific T-helper type 2 (Th2) cell line. We conclude that human lactoferrin acts as a maturation factor for B cells with regard to their phenotype and function.

Animals↗

PubMed1994

Lactoferrin cDNA. Expression and in vitro mutagenesis.

The full length copy DNA (cDNA) for human lactoferrin has been synthesised by the polymerase chain reaction (PCR) using sequence specific primers. The template was first strand cDNA, synthesised from human bone marrow RNA using oligo(dT) to prime DNA synthesis by MMLV reverse transcriptase. The full-length human lactoferrin cDNA has been expressed in baby hamster kidney (BHK) cells using the expression vector pNUT. The protein expressed from the cloned cDNA is secreted into the culture medium and yields of up to 40 mg per litre have been obtained. A mutant protein corresponding to the N-lobe of human lactoferrin (LfN) has also been expressed in BHK cells. The cDNA coding for this protein was produced by the introduction of stop codons into the region of the cDNA corresponding to the helix linking the N- and C-lobes of the native protein. LfN is also expressed as a secreted protein and has been obtained in high yield. LfN binds iron and has UV/Vis and ESR spectra which are virtually identical to the native protein. However, the pH at which iron is released from LfN is quite different to the pH of iron release from the native and the full-length recombinant protein. A number of mutations have been introduced into LfN by site-directed mutagenesis and the mutant proteins expressed in BHK cells. These mutations involve the iron binding ligands and have been designed to introduce some of the changes found in the C-lobe of melanotransferrin into LfN. An attempt has been made to express a protein corresponding to the C-lobe of human lactoferrin (LfC) by attaching the sequence for the signal peptide of lactoferrin to the cDNA sequences coding for the C-lobe.

Amino Acid Sequence↗

PubMed1994

Rapid assay of lactoferrin in keratoconjunctivitis sicca.

We compared measurement of lactoferrin concentration by the LactoCard solid phase ELISA assay with the LactoPlate radial immunodiffusion assay in tears of normal patients and those with keratoconjunctivitis sicca. The LactoCard, a new lactoferrin assay, allows rapid determination of tear lactoferrin concentration in 10-15 min, a notable improvement over the 3 days required of the LactoPlate. There was no statistically significant difference between the accuracy of the two assays in normal patients nor in those patients with a diagnosis of keratoconjunctivitis sicca. Both assays showed a significant decrease in tear lactoferrin concentration in patients with severe keratoconjunctivitis sicca when compared to normal patients. The LactoCard is a rapid and reliable means of measuring tear lactoferrin concentration in a clinical setting.

Adult↗

PubMed1994

Phospholipase D-mediated diradylglycerol formation coincides with H2O2 and lactoferrin release in adherent human neutrophils.

Polymorphonuclear leukocytes (PMNs) adherent to fibrinogen exhibit a delay in the onset of the respiratory burst in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP). Previously, we demonstrated that H2O2 release in adherent PMNs coincides with the exocytosis of lactoferrin-containing specific granules. Since diradylglycerol (DRG) has been implicated in PMN secretion and oxidant release, we measured DRG formation during PMN adhesion to fibrinogen. PMNs were added to fibrinogen-coated plastic in the presence of fMLP, and H2O2 release, lactoferrin release, and DRG formation measured over a time course of 120 min. H2O2 and lactoferrin release were not apparent until 45-60 min, reaching maximal levels by 120 min. In contrast, DRG concentration increased by 15-30 min, from 275 +/- 27 pmol/mg of protein in resting cells to 600 +/- 173 pmol/mg protein in cells exposed to fMLP. DRG levels returned to base line by 30-45 min (383 +/- 32 pmol/mg of protein) before increasing again between 60 and 120 min (944 +/- 230 pmol/mg of protein and 1632 +/- 351 pmol/mg of protein, respectively). Propranolol, an inhibitor of phosphatidate phosphohydrolase, caused a dose-dependent inhibition of both H2O2 and lactoferrin release, with maximal inhibition at 50-100 microM. Propranolol also inhibited the second, but not the first phase of DRG formation. Similarly, ethanol treatment completely blocked H2O2 and lactoferrin release, and the second phase of DRG formation. In the presence of ethanol, phospholipase D (PLD)-mediated formation of [3H]phosphatidylethanol from 3H-O-alkyl-phosphatidylcholine corresponded to the second, but not the first, phase of DRG formation (23,169 +/- 2,017 cpm/mg protein, ethanol versus 2,696 +/- 261 cpm/mg protein, control). These data indicate that DRG, generated through the activation of PLD, plays an important role in degranulation and oxidant release in adherent PMNs.

Cell Adhesion↗

PubMed1994

Characterization of a mitogen-response unit in the mouse lactoferrin gene promoter.

Lactoferrin is present in a variety of tissues and biological fluids; however, the amount differs significantly due to differential expressions. We have previously demonstrated that the mouse lactoferrin gene is regulated by estrogen through an estrogen-response DNA element located at -349, upstream from the transcription start site (+1). In this report, we characterized by deletion and mutation analyses a cluster of mitogen-response elements located between -80 and -40 of the mouse lactoferrin promoter. We demonstrated that the chimeric chloramphenicol acetyltransferase reporter constructs (the -103 to +1 sequence of the mouse lactoferrin gene) containing the mitogen-response unit of the lactoferrin gene were stimulated by cAMP, forskolin, 12-O-tetradecanoylphorbol-13-acetate, and epidermal growth factor/recombinant transforming growth factor-alpha (EGF/TGF-alpha) in a time- and dose-dependent manner. The sequence at position -52 to -40 (mLF-CRE) of the gene conferred transcriptional activation in the presence of forskolin, cyclic AMP, and 12-O-tetradecanoylphorbol-13-acetate in transiently transfected human endometrium carcinoma RL95-2 cells, whereas the region at -80 to -60 responded to EGF/TGF-alpha stimulation. Overexpression of the catalytic unit of protein kinase C or protein kinase A in the RL95-2 cells elevated the chloramphenicol acetyl-transferase activity of the reporter construct 5-6-fold. The mobility shift assay suggested that AP1 and CREB or related proteins participated in complex formation with the mLF-CRE, whereas different proteins bound to the EGF/TGF-alpha-response element.

Animals↗

PubMed1993

Within-subject variation of elastase/alpha 1-protease inhibitor complexes and lactoferrin in plasma.

Several studies have shown increased plasma concentrations of neutrophil elastase in complex with alpha 1-protease inhibitor and/or lactoferrin in inflammatory conditions, and serial measurements have been advocated in order to follow disease activity. However, data on the magnitude of the within-subject variation are necessary for evaluation of the significance of changes in results obtained on analysis of serial samples. Within-subject variation of elastase/alpha 1-protease inhibitor complexes and lactoferrin over a short time was studied in six young men who had blood samples drawn every 4 h over 2 days. Within-subject variation over a longer time was investigated in 12 healthy adults, 6 females and 6 males, who had blood samples drawn in the morning once a week for 10 weeks. From five of the females and five of the males, blood samples were also drawn every morning on 5 consecutive days during 1 week. Within-subject variations over hours, days, and weeks were estimated as 0.050, 0.124, and 0.148 for elastase/alpha 1-protease inhibitor complexes and as 0.101, 0.119, and 0.143 for lactoferrin. A tendency towards variation of LAC with menstrual cycle in fertile females was noticed. From within-subject variation, between-subject variation and analytical variation, indices of individuality were calculated as 1.1 and 1.8 for elastase/alpha 1-protease inhibitor complexes and lactoferrin, respectively. This means that within-subject variation for lactoferrin is quite small compared to between-subject variation, and the usefulness of reference limits is very limited, when interpreting results from individual patients. For elastase/alpha 1-protease inhibitor complexes, the use of reference limits might be more appropriate, although still not optimal.

Adult↗

PubMed1993

Ultrastructural localization of lactoferrin in the granules other than typical secondary granules of human neutrophils.

In neutrophils, lactoferrin is generally considered to be contained in secondary granules in which myeloperoxidase is lacking. However, it remains obscure whether lactoferrin is also contained in other organelles. We investigated subcellular localization of lactoferrin in human neutrophils by different immunoelectron microscopic methods. Lactoferrin was detected in secondary granules, and also in some large granules which could be distinguished from secondary granules based on their size and shape. These findings seem to indicate that the lactoferrin-positive large granules might represent primary ones or belong to another type of granules other than primary and secondary ones.

Cryoultramicrotomy↗

PubMed1996

Iron transport across Caco-2 cell monolayers. Effect of transferrin, lactoferrin and nitric oxide.

Differentiated Caco-2 colon carcinoma cell monolayers grown in bicameral chambers have been used as an in vitro model to study the effect of different carrier molecules on mucosal iron transport. Transfer of iron across the monolayers in the apical-to-basolateral direction was greater from ferric lactoferrin than from iron citrate, while very little transport occurred from Fe-transferrin. However, a greater proportion of iron was retained by the cells when Fe-citrate was the donor. Caco-2 cells expressed transferrin receptors (n = 1.3 x 10(5) /cell; Ka = 2 x 10(8) l/mol), but binding of lactoferrin, though substantial in quantity, had an affinity too low to measure. When monolayers were incubated with 125I-labelled lactoferrin or transferrin some 125I-activity was transported, but almost all was TCA-soluble, suggesting that degradation products rather than intact protein were being transported. Addition of 10 microM S-nitroso-N-acetyl-D,L-penicillamine (SNAP), which produces nitric oxide (NO) in solution, caused a significant increase in iron transport from ferric citrate, but not from Fe-lactoferrin or Fe-transferrin. It is concluded that in this in vitro system lactoferrin but not transferrin enhances mucosal iron transport, and that NO may play a regulatory role in iron absorption.

Biological Transport↗

PubMed1996

Cholinergic stimulation of lactoferrin and epidermal growth factor secretion by the human lacrimal gland.

The human lacrimal gland produces tear proteins, such as lactoferrin and epidermal growth factor (EGF), that have presumed biologic activity on the ocular surface. We hypothesized that secretion of these tear proteins by the lacrimal gland is neurally mediated. To test this hypothesis, we evaluated the secretion of lactoferrin and EGF from the human lacrimal gland (LG) after cholinergic stimulation. Human LG biopsies from two donors were sliced into sections weighing approximately 100 mg and were serially placed in wells containing Dulbecco's modified Eagle's medium (DMEM/F12; with or without atropine), followed by media alone, media containing carbamylcholine chloride (carbachol), and then media alone, each for 10 min. Supernatants were then assayed for lactoferrin and EGF by antibody sandwich enzyme-linked immunosorbent assay (ELISA). Both sets of LG explants showed statistically significant increases in supernatant concentrations of lactoferrin and EGF 10 min after cholinergic stimulation. These returned to prestimulation concentrations by 20 min. Atropine-pretreated explants showed no significant change in supernatant concentrations of these proteins after carbachol stimulation. The results of these studies indicate that cholinergic stimulation of the human LG results in increased secretion of the tear proteins lactoferrin and EGF. This suggests that the LG can respond to the ocular surface environment by increasing secretion of biologically active tear constituents through neural stimulation.

Adult↗

PubMed1997

Microparticle-enhanced nephelometric immunoassay of lactoferrin in human milk.

A microparticle-enhanced nephelometric immunoassay was developed for lactoferrin quantitation in human milk. It is based on the nephelometric measurement of the light scattered during the competitive immuno-agglutination of a microparticle-lactoferrin conjugate with an antilactoferrin antiserum. This immunoassay is sensitive (detection limit in reaction mixture, 0.2 mg/L) and can be performed in diluted milk (1/3,000 in reaction mixture), excluding any interference or sample pretreatment. It allowed the quantification of lactoferrin on a large range of concentrations (0.675-21.6 g/L) with accuracy (linear recovery in dilution-overloading assay) and precision (within- and between-run coefficients of variation from 3% to 6%). Changes in the lactoferrin concentration of human milk during lactation were determined in 190 samples. The concentration and ratio of lactoferrin vs. total protein were found to be significantly higher in colostrum (5.9 g/l, 29%) than in transitional milk (2.9 g/L, 22%) or mature milk (2.5 g/L, 24%).

Colostrum↗

PubMed1998

Crystal structure of a complex formed between proteolytically-generated lactoferrin fragment and proteinase K.

Lactoferrin is an iron binding glycoprotein with a molecular weight of 80 kDa. The molecule is divided into two lobes representing the N-terminal and C-terminal halves of the polypeptide chain, each containing an iron binding site. The serine proteinases such as trypsin, chymotrypsin, and pepsin hydrolyze lactoferrin into two unequal halves while proteinase K divides this protein into two equal halves. In the first step of hydrolysis by proteinase K, the C- and N-lobes, each having a molecular weight of approximately 40 kDa, are generated. In the next step, the lobes are further hydrolyzed into small molecular weight peptides. The proteinase K isolated from the hydrolyzed product does not show enzymatic activity suggesting that the enzyme is inhibited. Furthermore, the hydrolysis experiments on N-lobe and C-lobe showed that the inhibitory fragment came from the C-lobe. The purified lactoferrin fragment was found to be a decapeptide with an amino acid sequence of H2N-Val-Ala-Gln-Gly-Ala-Ala-Gly-Leu-Ala-COOH. The complex formed between proteinase K and lactoferrin fragment was crystallized by microdialysis. The crystals belonged to the monoclinic space group P2(1) with cell dimensions a = 44.4 A, b = 38.6 A, c = 79.2 A, beta = 105.8 degrees and Z = 2. The crystal structure has been determined at 2.4 A resolution. It has been refined to an R factor of 0.163 for 9044 reflections. The Lf-fragment forms several intermolecular interactions with proteinase K. The Ser-224 Ogamma and His-57 N epsilon2 move away to a distance of 3.68 A in the complex. In the crystal structure, Gln-3I (I indicates inhibitor i.e., lactoferrin fragment) is involved in a direct intermolecular interaction with a symmetry related proteinase K molecule through a strong hydrogen bond with Asp-254. The mode of intermolecular interactions in the complex conformational features of the enzyme and placement of the fragment with respect to the enzyme resemble with the molecular complex of proteinase K with its natural inhibitor PKI3 from wheat.

Animals↗