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PubMed2004

The efficacy of bovine lactoferrin in the treatment of cows with experimentally induced Escherichia coli mastitis.

The effect of bovine lactoferrin (Lf) was studied in experimental Escherichia coli mastitis, using enrofloxacin as a comparator. Mastitis was induced in six clinically healthy primiparous dairy cows by infusing 1500 colony-forming units of E. coli into a single udder quarter. The challenge was repeated into a contralateral quarter of the same cows 3 weeks later. At the first challenge, three cows were treated with 1.5 g of bovine lactoferrin intramammarily three times (12, 20 and 36 h postchallenge, PC), and the other three cows received 5 mg/kg of enrofloxacin (Baytril) parenterally (12, 36 and 60 h PC). Flunixin meglumine (2.2 mg/kg) was administered to all cows twice at 24-h intervals. During the second challenge, the treatments for the two groups were reversed. Intramammary challenge with E. coli produced clinical mastitis in all cows, but the severity of the disease varied markedly. No statistically significant differences between treatment groups were observed in clinical signs such as rectal temperature, rumen motility and general attitude. Milk somatic cell count, daily milk yield and bacterial counts in cows treated with Lf and those receiving enrofloxacin also did not differ significantly. However, a trend for a more rapid elimination of bacteria was seen in the cows treated with enrofloxacin. Milk NAGase activity also decreased significantly faster in the group treated with enrofloxacin. The concentration of lipopolysaccharide in milk compared with the number of bacteria was significantly lower in Lf than in enrofloxacin-treated cows (20 h PC).

Administration, Oral↗
PubMed1991

Human lactoferrin binding to Porphyromonas gingivalis, Prevotella intermedia and Prevotella melaninogenica.

Human isolates of Porphyromonas gingivalis (n = 16), Prevotella intermedia n = 82) and Prevotella melaninogenica (n = 18) from diseased periodontal pockets were examined for interaction with human lactoferrin (HLf) in a standardized 125I-labeled protein binding assay. The highest HLf binding was found in P. intermedia strains, followed by P. gingivalis and P. melaninogenica. Further characterization of the interaction was performed with 1 representative strain from each species. HLf binding to P. gingivalis reached a saturation instantly and was optimal at pH 5.0-6.5. The corresponding values for P. melaninogenica were 90 min and pH 3.0-5.5. The HLf binding to the 2 strains seem to be nonspecific. In contrast, P. intermedia demonstrated specific binding, and a time-saturability within 60 min with an optimal uptake at pH 6.0-7.5. Scatchard analysis implied 45,000 receptors per cell with an affinity constant of 5.5 x 10(-7) M on P. intermedia strain 4H. The binding capacity in all 3 strains was affected by the culture medium. HLf binding components in these strains were susceptible to heat or proteases. Binding was eliminated in P. gingivalis and was enhanced in P. intermedia and P. melaninogenica by periodate treatment. Unlabeled HLf or bovine lactoferrin effectively displaced labeled HLf binding. Various proteins and carbohydrates did not inhibit HLf binding. Our data suggest that HLf binds to these periodontitis-associated species and that this mechanism is distinct from the previously known ligand interactions in oral bacteria.

Acute-Phase Proteins↗
PubMed1983

Plasma lactoferrin measured by an enzyme-linked immunosorbent assay (ELISA). Measurements on adult and infant plasma.

The lactoferrin content of human plasma has been measured by an enzyme-linked immunosorbent assay. In cord blood the level was 0.02-0.3 mg/l, corresponding to 3-44 X 10-(10) mol/l lactoferrin; in plasma 5 d post partum the level had not changed. In adults the level was 0.02-0.2 in 29 out of 30 plasma samples and above 1 mg/l in 1 sample. Similar results were obtained with EDTA, citrate or heparin as anti-coagulant.

Adult↗
PubMed1984

Immunohistochemical distribution of immunoglobulins, lactoferrin, and lysozyme in human minor salivary glands.

The immunofluorescence technique was used to examine the distribution of immunoglobulin A and its subclasses, secretory component (SC), J chain, lactoferrin and lysozyme in labial and lingual (von Ebner's) glands. IgA-containing plasma cells were found in the connective tissue around intercalated or intralobular ducts and a few were noted around acini of both glands. IgA was detected in the apical cytoplasm of intercalated and intralobular duct cells and in acini of von Ebner's glands and in demilunes of labial glands. Most IgA-containing cells also stained for J chain. The ratio of IgA1:IgA2-containing cells was approximately equal in von Ebner's and labial glands. Cytoplasmic and surface membrane-related staining for SC was detected in epithelial cells of the intercalated and intralobular ducts in both glands, in the serous acini of von Ebner's gland, and in the demilunes of labial glands. Lactoferrin was found in serous acini, demilunes, intercalated and intralobular ducts. Lysozyme was found in acinar and intercalated ducts, but was rarely seen in intralobular ducts. These results disclose the presence of cells (plasma cells and epithelial cells) and their products (IgA and secretory component) that indicate the local production of secretory IgA in minor salivary glands.

Fluorescent Antibody Technique↗
PubMed1986

Lactoferrin, C-reactive protein, alpha-1-antitrypsin and immunoglobulin GA in cerebrospinal fluid in meningitis.

Cerebrospinal fluid measurements of lactoferrin and alpha-1-antitrypsin showed significant elevation in bacterial meningitis in children. 8 of 10 lactoferrin values and 6 of 11 alpha-1-antitrypsin values were above the upper range of controls. Both proteins correlated well with the total number of leukocytes in the cerebrospinal fluid. C-reactive protein, measured by either agglutination or radial immunodiffusion in the cerebrospinal fluid, failed to demonstrate any usefulness in diagnosing bacterial meningitis. Neither elevated serum C-reactive protein in cases of bacterial meningitis, nor sepsis, gave detectable concentrations of C-reactive protein in the cerebrospinal fluid.

Adolescent↗
PubMed1984

Neutrophil phagocytosis of treponema denticola as indicated by extracellular release of lactoferrin.

Lysosomal enzyme release from viable human neutrophils occurs during phagocytic activity in vivo. Phagocytosis of a strain of T. denticola, an oral spirochete, was indicated by the finding of lactoferrin in the extracellular medium of neutrophils challenged with this organism. The extracellular release of lactoferrin was dependent on duration of bacterial challenge, but peak concentration appeared at a later stage than seen in phagocytosis experiments with Escherichia coli, which served as a control. Neutrophil phagocytosis of T. denticola may be of importance as a defence factor in periodontal disease.

Escherichia coli↗
PubMed1999

Lactoferrin: a multifunctional glycoprotein.

Lactoferrin is an iron-binding glycoprotein found in milk, exocrine secretions of mammals, and in secondary granules from polymorphonuclear neutrophils. This review describes the wide spectrum of functions ascribed to lactoferrin, with special emphasis on the antimicrobial properties of this protein, and its derived peptides.

Animals↗
PubMed2006

Recombinant functional human lactoferrin expressed in baculovirus system.

Human lactoferrin (hLf) is a multifunctional iron-binding glycoprotein. In this study, we amplified hLf cDNA by reverse transcription-polymerase chain reaction from normal human mammary gland. The nucleotide sequence of the hLf was identical to the known hLf. We constructed a recombinant virus, vBm-hLf, harboring the hLf gene and exploited the BmN cells as host to produce recombinant human lactoferrin (rhLf). It was found that a recombinant protein with a molecular mass of approximately 78 kDa was expressed. Approximately 13.5 microg rhLf was purified from 1-2x10(5) BmN cells infected by vBm-hLf and the rhLf proved to be biologically active. This method established in our study will pave the way for efficient production of rhLf for further application of this protein in the future.

Animals↗
PubMed2006

Enteric-formulated lactoferrin was more effectively transported into blood circulation from gastrointestinal tract in adult rats.

We have previously demonstrated that intestinally infused bovine lactoferrin (bLF) is transported into the blood circulation via the lymphatic pathway, not via the portal circulation. Therefore, in the present study, we further investigated whether intragastrically infused enteric-formulated bLF (EF-bLF) was more efficiently absorbed than bLF from the intestine in adult rats. The rats were randomly divided into three groups: 30 and 300 mg kg(-1) non-enteric-formulated bLF (non-EF-bLF) groups and a 30 mg kg(-1) EF-bLF group. Thoracic lymph was collected from a thoracic lymph duct under general anaesthesia. Bovine lactoferrin was infused into the stomach or duodenal lumen via a needle for a period of over 1 min in a volume of 1 ml kg(-1). The bLF transported into the lymph was assayed quantitatively by double-antibody enzyme-linked immunosorbent assay (ELISA). Following the intragastric administration of bLF, the three groups showed almost the same lymph flow, but the bLF concentration in the lymph fluid in the EF-bLF group increased significantly and peaked 3 h after administration. With intraduodenal administration, the bLF concentration in the lymph fluid of the higher non-EF-bLF group was significantly higher than those of the other groups. The amount of absorbed bLF in the EF-bLF group was, however, about 10 times higher than that in the lower non-EF-bLF group, when it was administered intragastrically. These data show that enteric-formulated bLF is less susceptible to gastric pepsin and is more efficiently absorbed from the intestine than is non-enteric-formulated bLF.

Absorption↗
PubMed1977

A bactericidal effect for human lactoferrin.

Streptococcus mutans and Vibrio cholerae, but not Escherichia coli, were killed by incubation with purified human apolactoferrin. Concentrations of lactoferrin below that necessary for total inhibition resulted in a marked reduction in viable colony-forming units. This bactericidal effect was contingent upon the metal-chelating properties of the lactoferrin molecule.

Apoproteins↗
PubMed2000

Candidacidal activities of human lactoferrin peptides derived from the N terminus.

In light of the need for new antifungal agents, the candidacidal activities of human lactoferrin (hLF) and synthetic peptides representing the first, hLF(1-11), and second, hLF(21-31), cationic domains of its N terminus were compared. The results revealed that hLF(1-11) was more effective in killing fluconazole-resistant Candida albicans than hLF(21-31) and much more effective than lactoferrin, as determined microbiologically and by propidium iodide (PI) staining. By using hLF(1-11) and various derivatives, it was found that the second and third residues of the N terminus of hLF(1-11) were critical for its candidacidal activity. Detailed investigation to elucidate the mechanism of action of hLF(1-11) revealed a dose-dependent release of ATP by Candida upon exposure to hLF(1-11). Our observations that sodium azide reduced the PI uptake and candidacidal activity of hLF(1-11) and that, upon exposure to hLF(1-11), the fluorescent dye rhodamine 123 first accumulated inside the mitochondria and later was released into the cytoplasm indicate that the peptide triggers the energized mitochondrion. Furthermore, oxidized ATP, which interferes with the interaction of ATP with its extracellular receptors, blocked the candidacidal action of hLF(1-11), as measured microbiologically and by PI staining. Addition of ATP (or analogues) was not a sufficient stimulus to kill C. albicans or to act synergistically with suboptimal concentrations of the peptide. The main conclusions are that the first two arginines at the N terminus of hLF are critical in the candidacidal activity of hLF(1-11) and that extracellular ATP is essential but not sufficient for the peptide to exert its candidacidal activity.

Adenosine Triphosphate↗
PubMed2003

Bovine lactoferrin inhibits adenovirus infection by interacting with viral structural polypeptides.

We recently demonstrated that lactoferrin, an antimicrobial glycoprotein, can inhibit adenovirus infection by competing for common glycosaminoglycan receptors. This study further characterizes the antiadenovirus activity of the protein, thus demonstrating that lactoferrin neutralizes infection by binding to adenovirus particles and that its targets are viral III and IIIa structural polypeptides.

Adenoviridae↗
PubMed1983

Lactoferrin and transferrin fragments react with nitrite to form an inhibitor of Bacillus cereus spore outgrowth.

Tryptone is a pancreatic digest of casein which contains a heterogeneous mixture of substances that react with nitrite when heated in the presence of sodium thioglycolate to form a bacteriostatic agent which inhibits outgrowth of Bacillus cereus T spores. The substances which are precursors to the bacteriostatic agent can be fractionated on the basis of molecular size and charge and have properties which indicate that they are fragments of lactoferrin, an iron-binding glycoprotein. The bacteriostatic agent could also be formed directly from purified lactoferrin after it had been subjected to proteolysis. Transferrin, an analogous iron-binding protein found in animal serum, also showed these same properties. This system may be a useful model for studies of the mechanism and site of nitrite bacteriostatic action.

Bacillus cereus↗
PubMed2006

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

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

Animals↗
PubMed1983

Role of antibody and enterobactin in controlling growth of Escherichia coli in human milk and acquisition of lactoferrin- and transferrin-bound iron by Escherichia coli.

Growth of Escherichia coli NCTC 8623 in human milk was slow during the first 10 h of incubation, but this bacteriostatic effect had disappeared by 24 h. The bacteriostatic phase could be abolished by adding sufficient iron to saturate the lactoferrin in human milk, and also by adding supernatant from a 24-h milk culture or by adding enterobactin, an enterobacterial iron chelator. Growth in the presence of enterobactin was even more rapid than in the presence of excess iron. Partial loss of bacteriostatic activity could be achieved by absorbing the milk with bacterial antigens, but no clear correlation with removal of antibodies to O, K, or H antigens was apparent. When E. coli was grown in human serum trace-labeled with 59Fe, the organisms acquired iron from transferrin during growth. Cultivation of E. coli in a minimal medium supplemented with transferrin or lactoferrin doubly labeled with 125I and 59Fe showed that iron acquisition occurred without either assimilation or degradation of the iron-binding proteins.

Antibodies, Bacterial↗
PubMed1986

Immunohistochemical distribution of ferritin, lactoferrin, and transferrin in granulomas of bovine paratuberculosis.

Granulomatous lesions of bovine paratuberculosis contained ferritin, lactoferrin, and a small amount of transferrin, as demonstrated by the immunohistochemical method. Macrophages in the normal bovine ileum did not contain lactoferrin and transferrin; however, ferritin was found in individual macrophages of Peyer's patches. These results may help elucidate the relationship between intracellular growth of Mycobacterium paratuberculosis and the presence of iron-binding proteins in the granulomas.

Animals↗
PubMed1991

Identification and purification of transferrin- and lactoferrin-binding proteins of Bordetella pertussis and Bordetella bronchiseptica.

Bordetella pertussis and Bordetella bronchiseptica were both able to grow in iron-deficient medium when supplemented with iron-saturated human lactoferrin or transferrin but not with human apotransferrin. Direct contact between the transferrins and the Bordetella cells did not appear to be required for growth but considerably improved the growth of the organisms. Analysis of B. pertussis and B. bronchiseptica whole-cell lysates from cultures carried out in iron-deficient or iron-replete media revealed iron-repressible proteins (IRPs) of 27 kDa in B. pertussis and of 30, 32, 73.5, and 79.5 kDa in B. bronchiseptica. Iron-inducible proteins of 16, 23.5, 36.5, and 92.5 kDa and of 17, 23.5, 70, 84, and 91 kDa were also identified in B. pertussis and B. bronchiseptica, respectively. By use of affinity chromatography with iron-saturated human lactoferrin or transferrin as ligands, the 27- and 32-kDa IRPs from B. pertussis and B. bronchiseptica, respectively, were specifically isolated. By using iron-chelated affinity columns, we showed that these proteins exhibit an affinity for iron. Cell fractionation experiments indicated that both of these proteins are probably associated with the outer membrane. Growth of the organisms under modulating conditions showed that the production of these IRPs is not under the genetic transcriptional control of vir or bvg, the general virulence regulon in Bordetella spp.

Bacterial Outer Membrane Proteins↗
PubMed1993

A siderophore production mutant of Bordetella bronchiseptica cannot use lactoferrin as an iron source.

Bordetella bronchiseptica secreted a hydroxamate siderophore when grown in Fe-depleted medium. A Tn5lac insertion mutant of B. bronchiseptica, DBB22, did not produce this hydroxamate siderophore and was incapable of using lactoferrin as an Fe source. Our data suggest that B. bronchiseptica uses a siderophore for removal of Fe from lactoferrin and transferrin rather than relying upon a receptor for these host Fe-binding proteins.

Animals↗