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PubMed2005

Immobilised peptide displaying phages as affinity ligands. Purification of lactoferrin from defatted milk.

An affinity purification procedure for the direct purification of lactoferrin from defatted (skimmed) milk has been developed. The procedure is based on using selected phage clones expressing a peptide with high binding affinity for lactoferrin which were covalently coupled to macroporous poly(dimethylacrylamide) monolithic column. Large pore size (10-100 microm) of macroporous poly(dimethylacrylamide) makes it possible to couple long (1 microm) phage particles as ligands without any risk of blocking the monolithic column. Bound lactoferrin was eluted using 1M NaCl with a purity of >95%. The technique presents a good alternative to conventional immunoaffinity chromatography for purification of a protein of interest from complex samples due to (i) the robustness of the system in terms of recovery and ligand leakage and (ii) economical aspect in terms of low ligand cost.

Acrylamides↗
PubMed2004

Effects of human lactoferrin on the cytoplasmic membrane of Candida albicans cells related with its candidacidal activity.

Human lactoferrin is an innate host defence protein with antimicrobial activity that exerts a candidacidal effect in a cation concentration-dependent manner. We investigated the ability of this cationic protein (with an isoelectric point of 8.7) to permeabilize the cytoplasmic membrane of Candida albicans cells. Despite minor K(+)-release in lactoferrin-treated C. albicans cells, the killing effect was not related to an extensive membrane permeabilization, as indicated by: (a) the non-release of macromolecular cytosolic constituents; (b) the non-permeabilization for extracellular propidium iodide nor for intracellular accumulated calcein; and (c) the inability to disrupt the phospholipid bilayer of 8-aminonaphthalene-1,3,6, trisulfonic acid/p-xylene-bis-pyridiniumbromide-loaded liposomes. These results suggest that lactoferrin exerts its candidacidal effect through a mechanism different from membrane permeabilization described for other cationic peptides.

Antifungal Agents↗
PubMed2005

High level expression of functionally active human lactoferrin in silkworm larvae.

In this paper, recombinant human lactoferrin (rhLf) was expressed very well using Bombyx mori nuclear polyhedrosis baculovirus expression system. Infection of silkworm larvae with recombinant virus, vBm-hLf, the rhLf was efficiently secreted into larvae hemolymph and the concentration of product purified was about 65 microg/ml. The isolated rhLf molecular mass was approximately 78 kDa, lower than that of the human lactoferrin (hLf) standards, which may be due to incomplete glycosylation or protein degradation. Furthermore, the rhLf was characterized and its biological activities were evaluated by in vivo bioassay using dextran sodium sulfate (DSS)-induced colitis mouse model that mimics some characteristics of colitis disease in human. We conclude that silkworm expression system can be used successfully to express functional human lactoferrin.

Animals↗
PubMed2026

Reprogrammed Komagataella phaffii for enhanced secretory expression of human lactoferrin.

Human lactoferrin (hLF) is a multifunctional glycoprotein of the transferrin family derived from milk and mucosal secretions, which exhibits antibacterial, anti-tumor, and immunomodulatory functions, and is an important component of infant formula. Conventional methods for lactoferrin expression are often inefficient, primarily due to inadequate protein synthesis capabilities and poor stability within microbial hosts. Herein, a Komagataella phaffii yeast strain capable of high-level secretory expression of hLF was constructed by reprogramming the endoplasmic reticulum (ER) and vacuole using CRISPR/Cas9 technology. A dual-expression cassette containing the AOX1 promoter, an α-secretion signal peptide, the hLF gene, and a terminator was integrated into three different sites of the K. phaffii genome. The stepwise strategy combining expansion of the ER membrane involved in protein synthesis with knockout of vacuolar proteases further enhanced hLF production. Subsequently, 0.1 g/L FeCl₃ was added to the medium to reduce the toxicity of hLF and improve its stability. After high-density cultivation of K. phaffii through optimization of cultivation conditions in shake flasks and a 5 L bioreactor, the secretory intact hLF titer reached 2214 mg/L, representing a 76.3-fold increase achieved through these engineering strategies. In addition, antibacterial experiments demonstrated that this secretory hLF had a significant inhibitory effect on Escherichia coli, Staphylococcus aureus, and yeast. Overall, the developed K. phaffii protein expression platform enabled efficient production of lactoferrin, demonstrating its potential for expressing other lactoproteins.

Lactoferrin↗
PubMed2006

High-level expression of human lactoferrin in the milk of goats by using replication-defective adenoviral vectors.

The expression of human lactoferrin in the mammary gland is an attractive approach to diminish its current production cost. Previous attempts to produce lactorferrin in the milk of transgenic animals resulted in very high cost and uncertain results. In this paper, we have directly infused replication-defective adenovirus encoding human lactoferrin cDNA into the mammary gland of goats via the teat canal. In this way, we obtained a high level of expressed human lactoferrin up to 2g/L in the milk of goats. The milk serum was collected from the infected mammary gland 48 h post-infection and subjected to a 10% SDS-PAGE and Western blotting. A approximately 80-kDa protein was visualized after viral vector infection. Our results demonstrate that intraductal injection of recombinant replication-defective adenovirus vectors may provide a very useful tool for large-scale production of recombinant proteins of biopharmaceutical interest.

Adenoviridae↗
PubMed1991

Bovine lactoferrin mRNA: sequence, analysis, and expression in the mammary gland.

The mRNA sequence for bovine lactoferrin expressed in the mammary gland was determined by sequencing three over lapping cDNA clones and by direct sequencing of the mRNA. The mRNA (2351 bases) codes for a 708 amino acid protein with a 19 amino acid signal peptide immediately preceding a sequence identical to the N-terminal 40 amino acids reported for bovine lactoferrin. A putative destabilizing sequence (AUUUA) was identified in the 3'-untranslated region. The nucleic acid sequence and deduced amino acid sequence are highly homologous with other transferrin family members. Lactoferrin mRNA concentrations in bovine mammary tissue were quite low two days before parturition and during lactation but were high three days after the cessation of milking, a sharp contrast from the pattern of regulation of the other milk proteins.

Amino Acid Sequence↗
PubMed2002

Leishmania chagasi: uptake of iron bound to lactoferrin or transferrin requires an iron reductase.

Leishmania chagasi can utilize iron bound to transferrin, lactoferrin, or other chelates. We investigated the mechanism of iron uptake. Promastigotes preferentially took up iron in a reduced rather than an oxidized form, suggesting that extracellular iron must be reduced prior to internalization. Similar to literature reports, a 70-kDa protein in promastigote membrane-containing microsomes bound to [125I]-labeled transferrin. However, [125I]lactoferrin and [125I]albumin also bound a similar 70-kDa protein, suggesting that binding might not be specific. Both total and fractionated promastigotes exhibited an NADPH-dependent iron reductase activity. In contrast to trypanosomes, which take up transferrin through a specific receptor, these data support a model in which a parasite-associated or secreted reductase reduces ferric to ferrous iron, decreasing its affinity for the extracellular chelate and allowing it to be readily internalized by the parasite. This could account for the ability of the parasite to utilize iron from multiple sources in diverse host environments. Index Descriptors and Abbreviations. Index descriptors: Cryptococcus neoformans, Histoplasma capsulatum, iron, iron reductase, lactoferrin, L. chagasi, leishmaniasis, nutrient acquisition, protozoan, Saccharomyces cerevisiae, Trypanosoma brucei, Trypanosoma cruzi, transferrin; Abbreviations used: DNA, deoxyribonucleic acid; DTT, dithiothreitol; HBSS, Hanks' balanced salt solution; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NEM, N-ethylmaleimide; RNA, ribonucleic acid.

Animals↗
PubMed1998

Determination of the minor whey protein bovine lactoferrin in cheese whey concentrates with capillary electrophoresis.

In our present work we present the determination of bovine lactoferrin in whey concentrates as they are typically produced by milk and cheese industry after production of cheese. Due to the high total protein content the analysis of whey concentrate samples is difficult and even not possible by using capillary zone electrophoresis with UV detection. To enhance the detection sensitivity we applied a more promising approach by using affinity interactions in combination with laser-induced fluorescence detection. By mixing fluoresceine isothiocyanate (FITC)-conjugated polyanionic lipopolysaccharide with the mostly positively charged lactoferrin we found a significant migration time shift which is clearly dependent on the concentration of the added protein. In the second approach we developed an immunoassay using FITC-conjugated specific antibody against bovine lactoferrin. The results of the immunoassay measurements were compared with data obtained by standard enzyme-linked immunosorbent assay analysis.

Animals↗
PubMed1992

Lactoferrin and lysozyme deficiency in airway secretions: association with the development of bronchopulmonary dysplasia.

To test whether the presence of airway inflammatory markers differentiated babies with hyaline membrane disease (HMD) who recovered (n = 18) from those in whom bronchopulmonary dysplasia (BPD) developed (n = 18), tracheal aspirate samples from 36 newborn infants with HMD who underwent intubation were collected during days 1 to 28 of life and analyzed for the mucosal antimicrobial proteins lactoferrin and lysozyme. For babies with HMD in whom BPD developed, lactoferrin concentrations were decreased during the first 4 days of life (7 +/- 3, 14 +/- 3, 18 +/- 3, and 18 +/- 3 micrograms/ml, respectively) in comparison with those in babies with HMD who recovered (23 +/- 8, 29 +/- 6, 41 +/- 9, and 81 +/- 19 micrograms/ml); group differences reached statistical significance on days 3 and 4 (p less than 0.05). Lysozyme levels in the secretions of babies with BPD were also lower on day 3 (31 +/- 5 micrograms/ml) than in those of babies who recovered (54 +/- 7.5 micrograms/ml). For babies with BPD whose endotracheal tube remained in place beyond day 4, lysozyme levels on days 5 to 12 were significantly lower for those classified as having severe BPD than for those with mild to moderate BPD. Because lysozyme and lactoferrin are products of serous cells found in submucous glands, it seems possible that the relative immaturity of submucous glands may influence the development of BPD.

Bronchopulmonary Dysplasia↗
PubMed1993

Immunohistochemical detection of lactoferrin in different human glandular tissues with special reference to the exocrine pancreas.

The immunohistochemical detection of lactoferrin was carried out with the PAP technique on pancreatic tissue samples of 23 patients, operated for acute (13) or chronic (4) pancreatitis as well as for adenocarcinomas (6). In order to control our immunohistochemical technique and the antisera produced by us we studied some tissue samples of human mammary gland and parotis. We detected lactoferrin in the glands of parotis and mammae as well as of their secretions. In the pancreatic tissue we found a positive reaction only in granulocytes of inflammatory areas with the exception of a luminal reaction on the surface of acinar cells in one case of pancreatic adenocarcinoma. We would like to interpret our results with the hypothesis of granulocytic origin of immunochemically detectable lactoferrin in the pancreatic juice of patients, especially in cases of chronic pancreatitis.

Adenocarcinoma↗
PubMed1986

Studies on internalization and intracellular localization of membrane DNA in mouse peritoneal macrophages, by means of lactoferrin-gold complex.

It is an experimental fact that lactoferrin binds to DNA. In the present study, a lactoferrin-gold complex was first bound by the cell surface, then became internalized (inside coated or smooth vesicles). Intracellularly the complex appeared in tube-like or vesicle-like structures, which approximated the nucleus, and some vesicles even showed indications of association with the external nuclear membrane. Neither membrane binding, nor internization of the lactoferrin-gold complex had taken place in cells pretreated with DNase.

Animals↗
PubMed1978

Radioimmunoassay of lactoferrin in pancreatic juice as a test for pancreatic diseases.

Lactoferrin, a protein present in pancreatic juice and other exocrine secretions, was measured by radioimmunoassay in pure pancreatic juice obtained by endoscopic cannulation of the pancreatic duct. Lactoferrin concentrations were high in pancreatic juice from patients with chronic pancreatitis, but they were considerably lower in juice from control subjects and patients with carcinoma of the pancreas. The measurement of lactoferrin concentrations in pure pancreatic juice may be useful in the diagnosis of pancreatic diseases.

Chronic Disease↗
PubMed2001

Antiviral activities of lactoferrin.

Lactoferrin (LF) is an iron binding glycoprotein that is present in several mucosal secretions. Many biological functions have been ascribed to LF. One of the functions of LF is the transport of metals, but LF is also an important component of the non-specific immune system, since LF has antimicrobial properties against bacteria, fungi and several viruses. This review gives an overview of the present knowledge about the antiviral activities and, when possible, the antiviral modes of action of this protein. Lactoferrin displays antiviral activity against both DNA- and RNA-viruses, including rotavirus, respiratory syncytial virus, herpes viruses and HIV. The antiviral effect of LF lies in the early phase of infection. Lactoferrin prevents entry of virus in the host cell, either by blocking cellular receptors, or by direct binding to the virus particles.

Animals↗
PubMed1998

Inhibitory effects of bovine lactoferrin on intestinal polyposis in the Apc(Min) mouse.

Chemopreventive effects of bovine lactoferrin (bLF), previously shown to strongly inhibit intestinal carcinogenesis in rats (K. Sekine, E. Watanabe, J. Nakamura, N. Takasuka, D.J. Kim, M. Asamoto, V. Krutovskikh, T.H. Baba, T. Ota, M.A. Moore, M. Masuda, H. Sugimoto, H. Nishino, T. Kakizoe, H. Tsuda, Inhibition of azoxymethane-initiated colon tumor by bovine lactoferrin administration in F344 rats, Jpn. J. Cancer Res. 88 (1997) 523-526; K. Sekine, Y. Ushida, T. Kuhara, M. Iigo, H. Baba-Toriyama, M.A. Moore, M. Murakoshi, Y. Satomi, H. Nishino, T. Kakizoe, H. Tsuda, Inhibition of initiation and early stage development of aberrant crypt foci and enhanced natural killer activity in male rats administered bovine lactoferrin concomitantly with azoxymethane, Cancer Lett. 121 (1997) 211-216), on spontaneous intestinal polyp development were assessed in the ApcMin mouse, a model for both familial adenomatous polyposis and sporadic colon cancers. In the experiment, 54 mice at 6 weeks of age were given 2% bLF (15 mice), 0.2% bLF (15 mice) and AIN-93G (24 mice) as basal diet ad libitum for 8 weeks. An overall tendency for a reduction in the total number of polyps in the small intestine was evident in the bLF-treated animals, along with significant suppression in the jejunum at the 2% dose (P < 0.05, 68% of the control). In addition, body growth suppression, presumed to be due to anemia and/or intussusception as a consequence of numerous polyps in the intestine, was alleviated. No toxic effects were observed in the intestinal epithelium. Although not as obvious as observed for the rat case, the data suggest that bLF may be a chemopreventor of intestinal polyposis.

Animals↗
PubMed1998

Antiviral effect of bovine lactoferrin saturated with metal ions on early steps of human immunodeficiency virus type 1 infection.

Lactoferrin is a mammalian iron-binding glycoprotein present in many biological secretions, such as milk, tears, semen and plasma and a major component of the specific granules of polymorphonuclear leucocytes. The effect of bovine lactoferrin (BLf) in apo-form or saturated with ferric, manganese or zinc ions, on human immunodeficiency virus type 1 (HIV-1) infection in the C8166 T-cell line was studied. Both HIV-1 replication and syncytium formation were efficiently inhibited, in a dose-dependent manner, by lactoferrins. BLf in apo and saturated forms markedly inhibited HIV-1 replication when added prior to HIV infection or during the virus adsorption step, thus suggesting a mechanism of action on the HIV binding to or entry into C8166 cells. Likewise, the addition of Fe3+BLf prior to HIV infection and during the attachment step resulted in a marked reduction of the HIV-1 DNA in C8166 cells 20 h after infection. The potent antiviral effect and the high selectivity index exhibited by BLf suggest for this protein, in apo or saturated forms, an important role in inhibiting the early HIV-cell interaction, even though a post adsorption effect cannot be ruled out.

Adsorption↗
PubMed2000

Ribonuclease, cell-free translation-inhibitory and superoxide radical scavenging activities of the iron-binding protein lactoferrin from bovine milk.

The purpose of this study was to characterize the ribonuclease (RNase) and cell-free translation-inhibitory activities of lactoferrin isolated from bovine milk. It was found that bovine lactoferrin exhibited ribonucleolytic activity toward yeast transfer RNA in a dose-dependent manner. The pH optimum for this RNase activity was in the vicinity of 7.5. Lactoferrin exerted RNase activity on poly C with an activity of 2.15 U/mg. No activity was detected toward poly A, poly G, and poly U. The milk protein inhibited cell-free translation in rabbit reticulocyte lysate with an IC50 of 9.6 microM. The protein was devoid of N-glycosidase activity characteristic of ribosome inactivating proteins which also possess RNase and cell-free translation-inhibitory activities. It inhibited superoxide radical formation.

Animals↗
PubMed2006

Camel (Camelus dromedarius) immunoglobulin G, alpha-lactalbumin, serum albumin and lactoferrin in colostrum and milk during the early post partum period.

Colostrum and milk samples from twelve Tunisian camels were analysed for concentration of immunoglobulin G (IgG), alpha-lactalbumin (alpha-la), serum albumin (CSA) and lactoferrin throughout the first 14 milkings post partum (7 days of lactation) using single radial immunodiffusion assay. Concentrations (mg/ml, means+/-SD) at first milking were IgG, 100.7+/-60.4; alpha-la, 2.2+/-0.7; CSA, 8.5+/-3.6 and lactoferrin, 1.2+/-0.3. Large variations were recorded for IgG and CSA concentrations (11.8-211.1 mg/ml and 2.9-13.8 mg/ml respectively) Concentrations of IgG and CSA dropped abruptly in the subsequent milkings while alpha-la concentration increased until milking 5 and then decreased slowly. Lactoferrin dropped only from milking 7. Mean IgG concentrations were 3.6 and 2.5 mg/ml at milking 9 and 13 respectively. However, IgG concentration did not differ significantly, at the 1% level, from milkings 11 to 14. The contribution of CSA to the increase in whey proteins in early milks was greater than that described in the bovine and caprine species.

Animals↗
PubMed1998

Three-dimensional solution structure of lactoferricin B, an antimicrobial peptide derived from bovine lactoferrin.

The solution structure of bovine lactoferricin (LfcinB) has been determined using 2D 1H NMR spectroscopy. LfcinB is a 25-residue antimicrobial peptide released by pepsin cleavage of lactoferrin, an 80 kDa iron-binding glycoprotein with many immunologically important functions. The NMR structure of LfcinB reveals a somewhat distorted antiparallel beta-sheet. This contrasts with the X-ray structure of bovine lactoferrin, in which residues 1-13 (of LfcinB) form an alpha-helix. Hence, this region of lactoferricin B appears able to adopt a helical or sheetlike conformation, similar to what has been proposed for the amyloidogenic prion proteins and Alzheimer's beta-peptides. LfcinB has an extended hydrophobic surface comprised of residues Phe1, Cys3, Trp6, Trp8, Pro16, Ile18, and Cys20. The side chains of these residues are well-defined in the NMR structure. Many hydrophilic and positively charged residues surround the hydrophobic surface, giving LfcinB an amphipathic character. LfcinB bears numerous similarities to a vast number of cationic peptides which exert their antimicrobial activities through membrane disruption. The structures of many of these peptides have been well characterized, and models of their membrane-permeabilizing mechanisms have been proposed. The NMR solution structure of LfcinB may be more relevant to membrane interaction than that suggested by the X-ray structure of intact lactoferrin. Based on the solution structure, it is now possible to propose potential mechanisms for the antimicrobial action of LfcinB.

Amino Acid Sequence↗