SEARCH · PubMed Health

Results for “Lactoferrin”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources

PubMed2004

Blood lactoferrin release induced by running exercise in normal volunteers: antibacterial activity.

BACKGROUND: The aim of this study was to determine serum lactoferrin concentrations and serum antibacterial activity before and after running exercise. METHODS: Twenty-four healthy young men were randomly assigned to high, middle, or low intensity of exercise groups (5000 steps running at 180, 130, and 80 steps/min, respectively). Blood samples were collected at baseline and immediately, 1 and 4 h after exercise. Concentrations of circulating neutrophils, serum lactoferrin, iron in whole blood, and serum iron were measured. Antibacterial activity of serum was evaluated using live Micrococcus luteus. RESULTS: The numbers of circulating neutrophils were increased by 20.0% and 15.5% 1 h after exercise in high and middle groups (both P<0.01), respectively. Serum lactoferrin concentrations were significantly increased immediately after exercise by 48.3% and 33.0% in the high and middle groups (both P<0.01), respectively. No significant changes in total iron or serum iron concentrations were observed during the study. Antibacterial activities of serum collected immediately after exercise in the high and middle groups were significantly stronger than those before exercise, by 31.2% and 25.4% (both P<0.05), respectively. CONCLUSIONS: Serum lactoferrin concentrations are increased immediately after running exercise and may play an antibacterial role in host defenses before mobilization of neutrophils into the circulating pool.

Adult↗

PubMed2005

Quadruple therapy with lactoferrin for Helicobacter pylori eradication: a randomised, multicentre study.

BACKGROUND: Helicobacter pylori eradication rate with standard triple therapies is decreasing. Recently, lactoferrin administration has been shown to significantly increase the cure rate of 7-day rabeprazole, clarithromycin and tinidazole triple therapy. We assessed whether lactoferrin also increases the eradication rate of 7-day esomeprazole, clarithromycin and amoxycillin triple therapy as first-line treatment. METHODS: Overall, 133 consecutive patients with non-ulcer dyspepsia and H. pylori infection were randomised to receive either a standard 7-day triple therapy with esomeprazole 20mg b.i.d., clarithromycin 500 mg b.i.d. and amoxycillin 1g b.i.d. (68 patients) or a quadruple therapy comprising of the same regimen plus lactoferrin 200mg b.i.d. (65 patients). H. pylori at entry was assessed by endoscopy, while bacterial eradication was checked by (13)C urea breath test 4-6 weeks after treatment. RESULTS: H. pylori eradication following standard triple therapy was achieved in 53/68 (77.9%; 95% CI = 68-88) and in 53/66 (80.3%; 95% CI = 71-89) patients at ITT and PP analyses, respectively. Following the quadruple regimen, the infection was cured in 50/65 (76.9%; 95% CI = 67-87) and 50/64 (78.1%; 95% CI = 68-88) patients at ITT and PP analyses, respectively. No statistically significant difference emerged between the two therapeutic regimens, both at ITT (p = 0.9) and PP analyses (p = 0.9). Side effects were complained by seven (10.3%) patients and six (9.2%) patients following the triple and quadruple regimens, respectively (p = 0.9), with only one patient in the quadruple group interrupting the treatment due to side effects. CONCLUSIONS: Quadruple therapy with lactoferrin did not significantly increase the H. pylori cure rate of standard 7-day clarithromycin-amoxycillin based triple therapy in non-ulcer dyspepsia patients.

Amoxicillin↗

PubMed2006

Decreased lactoferrin levels in peritoneal fluid of women with minimal endometriosis.

OBJECTIVE: The aim of the study was to evaluate for the presence of lactoferrin (LTF) in peritoneal fluid (PF) of women with and without endometriosis. PATIENTS: Seventy-eight women were studied, including 49 women with endometriosis and, as a reference group, 29 patients with functional follicle ovarian cysts. RESULTS: Lactoferrin levels were detectable in all peritoneal fluid samples. Women with minimal endometriosis had lower PF lactoferrin concentrations compared to both patients with high revised American Fertility Society classification scores and women with follicle ovarian cysts. No significant difference in the peritoneal LTF levels was found between patients with stage II endometriosis, stage III or IV endometriotic disease and women with functional cysts of ovaries. CONCLUSIONS: Owing to its antibacterial properties lactoferrin is probably an important defense factor in the peritoneal cavity, however its role in the pathogenesis of endometriosis remains enigmatic.

Adolescent↗

PubMed2006

Identification of Toxoplasma gondii proteins binding human lactoferrin: a new aspect of rhoptry proteins function.

In this paper, we report on the isolation, purification and identification of two Toxoplasma gondii membrane proteins binding human lactoferrin. Parasite membrane proteins were isolated using the commercial Mem-PER Eukaryotic Membrane Protein Extraction System. After purification by lactoferrin affinity chromatography, three protein bands were detected with the molecular mass of 74, 63 and 58 kDa, two of which (63 and 58 kDa) specifically bound biotin labeled human lactoferrin as examined by competitive inhibition. Further identification of latter proteins by ESI/MS/MS amino acid sequencing technique revealed those proteins as Toxoplasma ROP4 (band 63 kDa) and ROP2 (band 58 kDa) antigens known to be involved in many mechanisms essential for the parasite pathogenicity, including host lactoferrin acquisition as determined in this study.

Amino Acid Sequence↗

PubMed2004

Anti-complement effects of lactoferrin-derived peptides.

Lactoferrin is an important biological molecule with many functions such as modulation of the inflammatory response, iron metabolism and antimicrobial defense. One effect of lactoferrin is the inhibition of the classical complement pathway. This study reports that antimicrobial peptides derived from the N-terminal region from both human and bovine lactoferrin, lactoferricin H and lactoferricin B, respectively, inhibit the classical complement pathway. No inhibitory effect of these peptides was observed on the alternative complement pathway in an AP50 assay. However, lactoferricin B reduced the inhibitory properties of serum against Escherichia coli in a concentration dependent manner. These results suggest that the N-terminal region of lactoferrin is the important part in the inhibition of complement activation and that these peptides possess other important properties than their antimicrobial effect.

Amino Acid Sequence↗

PubMed2006

A non-invasive quantitative assay to measure murine intestinal inflammation using the neutrophil marker lactoferrin.

Intestinal inflammation in mice is most frequently assessed by histology or FACS, processes that necessitate sacrificing mice. We developed a lactoferrin ELISA for murine feces to quantify intestinal inflammation in mice with enteric infections or colitis. Levels of fecal lactoferrin, a protein secreted by activated neutrophils, were consistent with neutrophil infiltration as assessed by histology, indicating that this fecal lactoferrin ELISA is a good alternative to histology. The fecal lactoferrin ELISA provides a non-invasive, quantitative assessment of intestinal inflammation, which should facilitate longitudinal studies of the development of and/or therapies reducing intestinal inflammation in individual mice and reduce the number of mice needed for such studies.

Animals↗

PubMed2005

Anti-lactoferrin toxicity and elevated iron: The environmental prerequisites which activate susceptibility to tuberculosis infection?

The maintenance and multiplication of Mycobacteria tuberculosis (TB) and many other species of parasitic pathogen are dependent to varying, largely unidentified degrees upon a source of free iron within the host tissues. To combat these infections, the mammalian biosystem expresses an iron binding exocrine protein, lactoferrin, which scavenges and competes for free iron, thereby starving the parasite of its vital iron supply. TB mycobacteria are naturally endemic in the external environment, and once a latent, low level TB infection is established within the host tissues, a full blown proliferation of the mycobacteria population can be activated as soon as the levels of free iron are elevated within the host tissues. The increase in iron can be induced by several environmental and/or eco-genetic prerequisites that operate either singly or in a synergistic combination; factors such as iron rich water/foods, increased iron uptake/retention in the host tissues or an environmental/genetic induced reduction in the turn over of iron binding lactoferrin mediated immune defence against TB. Susceptibility to the full blown proliferation of TB pathogenesis is markedly increased as a result. This paper proposes that the recent dramatic increase in the incidence of bovine/badger TB across the UK can be correlated to the overall increase in acidification of the agricultural ecosystem, which, in turn, has induced a substantial elevation of soluble iron within the farm foodchain, thereby exacerbating susceptibility to TB infection within any mammalian species that is dependent upon these high iron ecosystems. The problem is further compounded by the routine use of 'anti-lactoferrin' levamisole based cattle wormers, which 'sensitise' the levamisole's target receptors, thereby down regulating the secretion of the iron binding lactoferrin molecule, which causes a reduction in the host's main line of defence against TB infection.

Animals↗

PubMed2004

Lactoferrampin: a novel antimicrobial peptide in the N1-domain of bovine lactoferrin.

The antimicrobial activity of bovine lactoferrin is attributed to lactoferricin, situated in the N1-domain. Based on common features of antimicrobial peptides, a second putative antimicrobial domain was identified in the N1-domain of lactoferrin, designated lactoferrampin. This novel peptide exhibited candidacidal activity, which was substantially higher than the activity of lactoferrin. Furthermore, lactoferrampin was active against Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa, but not against the fermenting bacteria Actinomyces naeslundii, Porphyromonas gingivalis, Streptococcus mutans and Streptococcus sanguis. Notably, lactoferrampin is located in the N1-domain in close proximity to lactoferricin, which plays a crucial role in membrane-mediated activities of lactoferrin.

Amino Acid Sequence↗

PubMed1999

Effects of topical application of free and liposome-encapsulated lactoferrin and lactoperoxidase on oral microbiota and dental caries in rats.

Four groups of rats were inoculated with Streptococcus sobrinus ATCC 33478 and fed a cariogenic diet for 42 days. Topical treatment with either distilled water, sodium fluoride (0.2%), a solution containing lactoferrin and lactoperoxidase, or a solution containing liposome-encapsulated lactoferrin and liposome-encapsulated lactoperoxidase was applied at intervals for 35 days. Caries incidence in groups treated with liposome-encapsulated lactoferrin and lactoperoxidase was significantly lower than in control groups. The number of viable Strep. sobrinus and the proportion of Strep. sobrinus in the total counts were significantly higher in liposome-treated groups. Free lactoferrin and lactoperoxidase did not cause a significant reduction in caries incidence.

Administration, Oral↗

PubMed2002

Detection and quantitation of lactoferrin in bovine whey samples by reversed-phase high-performance liquid chromatography on polystyrene-divinylbenzene.

An existing RP-HPLC method for the measurement of the major bovine whey proteins in bovine whey samples and powders has been extended to include the analysis of the minor bovine whey protein lactoferrin. Lactoferrin could be detected and quantitated at levels down to 0.2 microg and linear calibration was observed between 0.2 and 30 microg. Reliable quantitation of lactoferrin in whey samples could be achieved provided the bovine serum albumin to lactoferrin ratio did not exceed 10:1. Quantitative data obtained by the RP-HPLC method compared favourably with data obtained by Mono S analytical chromatography.

Animals↗

PubMed2002

Characterization of monoclonal antibodies against human lactoferrin.

The iron-binding glycoprotein human lactoferrin (hLF) is involved in the host defense against infection and is a modulator of inflammatory reactions. We generated monoclonal antibodies (mAbs) to hLF as tools to assist both structure-function studies and the development of recombinant human lactoferrin for applications in human health care. Binding experiments with ten distinct anti-hLF mAbs to tryptic and recombinant hLF fragments in ELISA and/or on immunoblots revealed that five mAbs bound to conformational epitopes residing in the N-lobe (residues 1 to 334), whereas the other five bound to C-lobe conformational epitopes (residues 335 to 692). None of the mAbs bound to hLF denatured upon reduction. Monoclonal antibody E11 appeared to bind to the arginine-rich N-terminus of hLF, which is the binding site for heparin, bacterial lipopolysaccharide, human lysozyme, DNA and receptors. The dissociation constant of the distinct mAbs for hLF ranged from 0.5 to 18 nM, without differences in affinity for unsaturated or iron-saturated hLF, indicating that the conformational changes subject to incorporation of iron do not seem to affect the exposure and/or conformation of the antibody epitopes. The mAbs did not bind to human transferrin, a protein closely related to hLF in size, primary amino acid sequence and structure. Two C-lobe specific mAbs, E2 and E8, cross-reacted with bovine and/or porcine lactoferrin, indicating that human, bovine and porcine lactoferrin share antigenic determinants. This panel of mAbs will be used to develop quantitative and qualitative immunoassays for hLF and to delineate which regions of hLF are relevant to its anti-infective and anti-inflammatory properties.

Animals↗

PubMed2003

Crystal structure of a proteolytically generated functional monoferric C-lobe of bovine lactoferrin at 1.9A resolution.

This is the first crystal structure of a proteolytically generated functional C-lobe of lactoferrin. The purified samples of iron-saturated C-lobe were crystallized in 0.1 M Mes buffer (pH 6.5) containing 25% (v/v) polyethyleneglycol monomethyl ether 550 M and 0.1 M zinc sulphate heptahydrate. The X-ray intensity data were collected with 300 mm imaging plate scanner mounted on a rotating anode generator. The structure was determined by the molecular replacement method using the coordinates of the C-terminal half of bovine lactoferrin as a search model and refined to an R-factor of 0.193 for all data to 1.9A resolution. The final model comprises 2593 protein atoms (residues 342-676 and 681-685), 124 carbohydrate atoms (from ten monosaccharide units, in three glycan chains), one Fe(3+), one CO(3)(2-), two Zn(2+) and 230 water molecules. The overall folding of the C-lobe is essentially the same as that of C-terminal half of bovine lactoferrin but differs slightly in conformations of some of the loops and reveals a number of new interactions. There are 20 Cys residues in the C-lobe forming ten disulphide links. Out of these, one involving Cys481-Cys675 provides an inter-domain link at 2.01A while another Cys405-Cys684 is formed between the main C-lobe 342-676 and the hydrolyzed pentapeptide 681-685 fragment. Six inter-domain hydrogen bonds have been observed in the structure whereas only four were reported in the structure of intact lactoferrin, although domain orientations have been found similar in the two structures. The good quality of electron density has also revealed all the ten oligosaccharide units in the structure. The observation of two metal ions at sites other than the iron-binding cleft is another novel feature of the present structure. These zinc ions stabilize the crystal packing. This structure is also notable for extensive inter-molecular hydrogen bonding in the crystals. Therefore, the present structure appears to be one of the best packed crystal structures among the proteins of the transferrin superfamily.

Animals↗

PubMed2003

Lactoferrin--a multifunctional protein with antimicrobial properties.

Lactoferrin is a member of the transferrin family of iron-binding proteins. Numerous functions have been reported and continue to be reported for the protein, some of which are related to its iron-binding properties. Its extensive antimicrobial activities were originally attributed to its ability to sequester essential iron, however, it is now established that it possesses bactericidal activities as a result of a direct interaction between the protein or lactoferrin-derived peptides. This article reviews the antimicrobial activities of lactoferrin and discusses the potential mode of action of lactoferrin-derived cationic peptides against Gram-negative bacteria in the light of recent studies.

Animals↗

PubMed2001

High pressure increases bactericidal activity and spectrum of lactoferrin, lactoferricin and nisin.

We have studied the inactivation of a panel of eight test bacteria (two Escherichia coli strains, Salmonella enteritidis, Salmonella typhimurium, Shigella sonnei, Shigella flexneri, Pseudomonas fluorescens and Staphylococcus aureus) by high pressure in the presence of bovine lactoferrin (500 microg/ml), pepsin hydrolysate of lactoferrin (500 microg/ml), lactoferricin (20 microg/ml) and nisin (100 IU/ml). None of these compounds, at the indicated dosage, were bactericidal when applied at atmospheric pressure, except nisin, which caused a low level of inactivation of the bacteria. Under high pressure, lactoferrin, lactoferrin hydrolysate and lactoferricin displayed bactericidal activity against some of the test bacteria, however, the former had a narrower bactericidal spectrum than the two latter compounds. The bactericidal efficiency and spectrum of nisin were also enhanced under high pressure. The sensitisation of the test bacteria to these antimicrobials under pressure was transient, since no bactericidal activity was observed when bacteria were pressure treated before exposure to the compounds. We propose a mechanism of pressure-promoted uptake of these antimicrobial proteins and peptides in gram-negative bacteria to explain this sensitisation.

Anti-Bacterial Agents↗

PubMedDate not supplied

Normal distribution of lysozyme- and lactoferrin-secreting cells in the chinchilla tubotympanum.

The distribution of the antibacterial enzyme lysozyme- and lactoferrin-secreting cells in the tubotympanum of normal chinchillas was studied using an immunohistochemical technique. The middle ear mucosa contained lysozyme-secreting cells and lactoferrin-secreting cells. The former were localized primarily in the columnar epithelium area and the latter primarily in the cuboidal epithelium area (that contains serous cells) of the transitional zone. In the eustachian tube, the lysozyme was localized in goblet cells of the mucosal epithelium and mucous cells of the glands, while lactoferrin was localized in serous cells of the glands. Our results indicate that secretory lysozyme and lactoferrin are secreted by different cell types (mucous or serous), supporting the notion of heterogeneity of the secretory cells of the tubotympanum. This finding is consistent with the concept that antibacterial enzyme secretion is an integral part of the normal mucosal defense system in the tubotympanum.

Animals↗

PubMed2000

Human lactoferrin proteolytic activity: analysis of the cleaved region in the IgA protease of Haemophilus influenzae.

Human lactoferrin proteolytically cleaves and inactivates two colonization factors of non-typable Haemophilus influenzae, the IgA protease precursor protein (Iga), and Hap, the non-pilus adhesin by which microoganisms adhere to host epithelial cells and form microcolonies. Iga and Hap are homologous proteins that are members of the autotransporter family of secreted proteins expressed by gram-negative bacteria. Studies of Iga cleaved by lactoferrin, reported here, show that proteolysis occurred within the helper region of Iga (Iga(beta)) domain which anchors the autotransporter within the Haemophilus outer membrane. The amino-terminus of the extracted Iga protein was not modified. The location of the proteolytic active site in human lactoferrin is under study. Lactoferrin proteolysis may attenuate pathogenicity of H. influenzae, an important cause of otitis media.

Amino Acid Sequence↗

PubMed2001

The binding of lactoferrin to glycosaminoglycans on enterocyte-like HT29-18-C1 cells is mediated through basic residues located in the N-terminus.

Although lactoferrins (Lfs) isolated from milk of various mammals exhibit a close structural relationship, they show species-specific binding to cells. To define the specificity of recognition of human (hLf), bovine (bLf) and murine (mLf) lactoferrin by human intestinal cells, we analysed the binding of the three proteins to a subclone derived from human carcinoma cell line HT29. We observed that hLf and bLf interact with two types of binding sites (K(d): 63+/-22 nM; 0.7+/-0.2 microM) while mLf was recognized only by the lowest affinity binding sites with a lower number of binding sites. Using N-terminal deleted human Lf variants, we found that the sequence G(1)RRRR(5) is mainly responsible for the interactions with HT29 cells. Lactoferrin-binding sites on the surface of HT29 cells were further identified as heparan sulphate and chondroitin sulphate glycosaminoglycans. We conclude that the presence of the sequence A(1)PRK(4) in bLf and K(1)ATT(4) in mLf provides an insight into why the interaction of bLf with cell membrane-associated glycosaminoglycans is similar to that of hLf and why binding of these lactoferrin species differs from that of murine Lf.

Amino Acid Sequence↗

PubMed1999

Evaluation of bovine lactoferrin as a topical therapy for chemotherapy-induced mucositis in the golden Syrian hamster.

Bovine lactoferrin was applied topically to the oral mucosa of Syrian hamsters and assessed for its ability to decrease the severity of chemotherapy-induced oral mucositis. Results indicated that the chemotherapy agent 5-fluorouracil (5-FU) administered to hamsters on days 0 and 2 produced severe leukopenia between days 4 and 7 of the trial, and that severity of oral mucositis coincided with the suppressed immune state in these animals. Bovine lactoferrin applied continuously to oral wounds in hamsters induced by a combination of chemotherapy treatment and mild abrasion of the cheek pouch, failed to decrease the severity of mouth ulcers relative to a group receiving BSA as a control protein source. Hamster cheek pouches treated twice daily with lactoferrin had a significantly worse condition score between days 6 and 8, and days 12 and 13 (p < 0.05 to p < 0.001), a higher ulcer score between days 6 and 15 (p < 0.05 to p < 0.001) and larger ulcer area between days 7 and 14 (p < 0.05 to p < 0.001) compared to animals administered the control protein. Body weight changes between treatment and control groups showed no significant difference over the trial period. In contrast to the pre-study hypothesis, we report a detrimental effect from topical administration of bovine lactoferrin to the wounded oral mucosa of immunocompromised hamsters.

Animals↗