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PubMed2002

A novel localized amyloidosis associated with lactoferrin in the cornea.

We report a novel localized amyloidosis associated with lactoferrin. To elucidate the precursor protein of corneal amyloidosis associated with trichiasis, we analyzed amyloid deposits from three patients by histopathology and biochemistry. Amyloid deposits showed immunoreactivity, confirmed by electron microscopy, for only anti-human lactoferrin antibody. Electrophoresis of amyloid fibrils revealed lactoferrin with and without sugar chains; N-terminal sequence analysis revealed full-length lactoferrin and a truncated tripeptide of N-terminal amino acids, Gly-Arg-Arg. Carboxymethylated wild-type lactoferrin formed amyloid fibrils in vitro. Lactoferrin gene analysis in the three patients revealed a Glu561Asp mutation in all of the patients and a compound heterozygote of Ala11Thr and Glu561Asp mutations in one patient. A heterozygotic Glu561Asp mutation appeared in 44.8% of healthy Japanese volunteers, suggesting that the mutation may not be an essential mutation for amyloid formation (p = 0.104). Results thus suggest that lactoferrin is this precursor protein.

Adult↗

PubMed1978

Lactoferrin content of peripheral blood cells.

The peripheral blood of 60 normal adults was separated into plasma, red cells, neutrophils, lymphocytes, monocytes and platelets. Lactoferrin concentrations were measured in the plasma and cell extracts and compared to those of lysozyme. The neutrophil lactoferrin content in males and post-menopausal females was found to be significantly higher than in pre-menopausal females. A small amount of lactoferrin was found in association with monocytes, but not with lymphocytes, erythrocytes and platelets. Neutrophil lysozyme concentrations did not exhibit any variation with sex and age; but the level in monocytes was higher than that in neutrophils. No correlation was observed between individual neutrophil lactoferrin values and the plasma level. Immunofluorescent studies showed neutrophils to have a lobulated pattern suggestive of nuclear staining. Monocytes did not show direct staining, but exhibited a peripheral pattern after prior exposure to lactoferrin--confirming the existence of a surface receptor. Gel chromatography indicated that neutrophil lactoferrin is in a polymerized or complexed form which elutes with the void volume on Sephadex G-200; serum lactoferrin consists of two forms, one of which also elutes with the void volume on Sephadex G-200.

Adult↗

PubMed1989

Localization of lactoferrin in the male reproductive tract.

The immunohistochemical localization of lactoferrin in the normal human prostate, seminal vesicle, vas deferens, epididymis and testis was studied using the peroxidase-antiperoxidase method at the light and electron microscopical level. Lactoferrin immunoreactivity was localized in the glandular epithelial cells and granulocytes in the prostate and seminal vesicle. In the prostate, lactoferrin showed an uneven distribution; some of the glands contained exclusively positive cells and others were completely lactoferrin negative, while the rest contained scattered positive cells. The seminal vesicles were divided into three segments, and their lactoferrin content varied significantly although it was always epithelial. The ductus deferens, epididymis and testis contained no lactoferrin. In conclusion, lactoferrin was found in the prostate and seminal vesicles, but not in the testis.

Aged↗

PubMed1989

Lactoferrin-binding sites at the surface of HT29-D4 cells. Comparison with transferrin.

The binding of 125I-lactoferrin to HT29-D4 cells, a clone of HT29 cells, was studied and compared to the binding of 125I-transferrin to the same cells. The binding of the two iron-transport proteins is saturable and reversible suggesting the presence of specific receptors for each protein. Scatchard analysis suggests the existence of binding sites for lactoferrin with the relatively high equilibrium dissociation constant, Kd1 of 408 nM. Additionally, the cell is capable of binding large amounts of lactoferrin with very low affinity, probably in a non-receptor intermediate fashion. The dissociation constant of transferrin and its receptor was calculated 9.29 nM which corresponds well to values found in the literature. In contrast to lactoferrin, the cell was capable of binding only low amounts of transferrin in a non-receptor intermediate fashion. After chemical crosslinking of lactoferrin to the cell surface, the radiolabeled lactoferrin was found in a complex of molecular mass 300 kDa. Crosslinking of transferrin resulted in a complex of much higher molecular mass. These data clearly show a binding site for lactoferrin different from the transferrin receptor. Only if competition experiments were performed with a high molar excess of both ligand proteins did a small percentage of either of the two ligands crossreact with the receptor for the other, possibly due to a structural similarity of the two glycoproteins.

Adenocarcinoma↗

PubMed1996

Cryptic domains of a 60 kDa heat shock protein of Helicobacter pylori bound to bovine lactoferrin.

Bovine lactoferrin binds to a 60 kDa heat shock protein of Helicobacter pylori. Binding ability was related to human immunoglobulin G because bovine lactoferrin binding proteins were isolated by extraction of cell surface associated proteins with distilled water, applied on IgG-Sepharose and nickel sulphate chelate affinity chromatography. Binding was demonstrated by Western blot after purified protein was digested with alpha-chymotrypsin and incubated with peroxidase-labeled bovine lactoferrin. Binding was inhibited by bovine lactoferrin, lactose, rhamnose, galactose, and two iron-containing proteins, ferritin and haptoglobin. Helicobacter pylori binds ferritin and haptoglobin via charge or hydrophobic interactions because this binding was not inhibited by specific and various glycoproteins or carbohydrates. Carbohydrate moieties of bovine lactoferrin molecules seem to be involved in binding because glycoproteins with similar carbohydrate structures strongly inhibited binding. Scatchard plot analysis of the binding of peroxidase-labeled bovine lactoferrin to H. pylori cells yielded a kd 2.88 x 10(-6) M. In addition, binding of H. pylori cells to bovine lactoferrin was enhanced when bacteria treated with pepsin or alpha-chymotrypsin after isolation from iron-restricted and iron-containing media.

Animals↗

PubMed1997

Augmented inhibition of growth of Candida albicans by neutrophils in the presence of lactoferrin.

The combined inhibitory effects of neutrophils and lactoferrins on the growth of Candida albicans were examined. Murine or human neutrophils partially inhibited growth of C. albicans when cultured with C. albicans in vitro. The growth inhibition was augmented by a combination of neutrophils and more than 30 microg/ml of bovine lactoferrin or 1 microg/ml of human lactoferrin, concentrations less than 1/10-1/200 their inhibiting concentrations when used alone. The inhibition of C. albicans was also enhanced by combination of neutrophils and bovine apolactoferrin or iron-bound holo-lactoferrin, but not by transferrin. Combination effects of neutrophils and lactoferrin were also observed in a condition where there was no contact between neutrophils and Candida cells. These results suggest that neutrophils inhibit the growth of C. albicans regardless of whether there is direct contact between them and Candida cells: neutrophil growth inhibition effects were augmented in the presence of a physiological concentration of lactoferrin, perhaps through some action of lactoferrin other than chelation of ferric ion.

Animals↗

PubMed1996

Degradation of lactoferrin by periodontitis-associated bacteria.

The degradation of human lactoferrin by putative periodontopathogenic bacteria was examined. Fragments of lactoferrin were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and measured by densitometry. The degradation of lactoferrin was more extensive by Porphyromonas gingivalis and Capnocytophaga sputigena, slow by Capnocytophaga ochracea, Actinobacillus actinomycetemcomitans and Prevotella intermedia, and very slow or absent by Prevotella nigrescens, Campylobacter rectus, Campylobacter sputorum, Fusobacterium nucleatum ssp. nucleatum, Capnocytophaga gingivalis, Bacteroides forsythus and Peptostreptococcus micros. All strains of P. gingivalis tested degraded lactoferrin. The degradation was sensitive to protease inhibitors, cystatin C and albumin. The degradation by C. sputigena was not affected by the protease inhibitors and the detected lactoferrin fragments exhibited electrophoretic mobilities similar to those ascribed to deglycosylated forms of lactoferrin. Furthermore a weak or absent reactivity of these fragments with sialic acid-specific lectin suggested that they are desialylated. The present data indicate that certain bacteria colonizing the periodontal pocket can degrade lactoferrin. The presence of other human proteins as specific inhibitors and/or as substrate competitors may counteract this degradation process.

Aggregatibacter actinomycetemcomitans↗

PubMed1997

Human lactoferrin receptor activity in non-encapsulated Haemophilus influenzae.

Since the ability of bacteria to compete with lactoferrin for iron contributes to the pathogenesis of mucosal infections, the presence of lactoferrin receptor activity in non-encapsulated Haemophilus influenzae was investigated. The growth of 18 H. influenzae isolates from the sputum samples of chronic bronchitis patients and of six of seven H. influenzae throat isolates from healthy adults was stimulated by iron saturated human lactoferrin. Apo-lactoferrin did not stimulate the growth of H. influenzae. Human lactoferrin binding to iron limited bacteria was detected for 16 H. influenzae strains from chronic bronchitis patients and for five of seven isolates from healthy adults. We conclude that the majority of H. influenzae isolates tested bind human lactoferrin and that the iron from lactoferrin is used for growth.

Adult↗

PubMed1977

Myeloperoxidase and lactoferrin of blood neutrophils and plasma in chronic granulocytic leukaemia.

Myeloperoxidase, restricted to primary granules, and lactoferrin, restricted to secondary granules, were determined in plasma and neutrophils of peripheral blood in chronic granulocytic leukaemia (CGL). Plasma myeloperoxidase was increased 2-3 times while plasma lactoferrin increased 2-8 times. This discrepancy indicates different modes of release or elimination. A correlation was found between the leucocyte count and plasma myeloperoxidase or lactoferrin. A correlation was also found between cellular and plasma levels of lactoferrin but not for myeloperoxidase indicating the source for plasma lactoferrin to be circulating leucocytes, which may not be the case for plasma myeloperoxidase. Decreased neutrophil lactoferrin was found in 71% of the CGL cases while myeloperoxidase was decreased in 18%. Serial studies on individual CGL subjects showed low cellular lactoferrin during phases with rapidly expanding leucocytosis indicating defective maturation of neutrophils or abnormal release because of prolonged intravascular life-span.

Adult↗

PubMed1986

Lack of correlation between iron stores and plasma lactoferrin concentration.

Plasma lactoferrin concentration and indices of iron nutrition including P-Ferritin, P-iron, total iron binding capacity and percentage saturation were measured in 75 otherwise normal females. This was done in order to evaluate previous reports that neutrophil lactoferrin content was altered by variations in iron storage status. Since P-Lactoferrin is derived from and hence reflects neutrophil lactoferrin content it would seem reasonable to assume that P-Lactoferrin would vary in accordance with iron stores. However, there was no statistically significant difference in P-Lactoferrin concentration between iron deficient subjects and those who were iron replete. Furthermore, there was no statistically significant correlation between any iron related parameter and P-Lactoferrin concentration.

Female↗

PubMed1995

The relationship between elastase and lactoferrin in healthy, gingivitis and periodontitis sites.

OBJECTIVES: To compare the relative amounts of elastase (primary polymorphonuclear leucocyte granule constituent) and lactoferrin (secondary PMN granule constituent) in the gingival crevicular fluid (GCF) of healthy, gingivitis and periodontitis sites. DESIGN: This cross-sectional study looked at the two GCF constituents in three categories of disease status within the same subject. MATERIALS AND METHODS: Patients with chronic adult periodontitis were screened and those exhibiting all three types of sites ie periodontally healthy, gingivitis and periodontitis sites were recruited (n=10) and had GCF collected from the three sites. Lactoferrin and elastase were measured in eluates of GCF by enzyme-linked immunosorbent assay. RESULTS: The absolute amount of lactoferrin measured in ng per 30 s samples was significantly lower in healthy and gingivitis sites as compared to periodontitis sites; however this difference failed to reach significance when the concentration of lactoferrin in GCF was used as the analytical unit. No significant differences were found for elastase levels at any sites when expressed as either absolute amounts or concentrations. Secondary granule release, as evidenced by lactoferrin levels, occurs during cell migration and the process is independent of primary granule release, which is thought to correlate with PMN activation. The relationship between granule constituents in the samples showed significant differences, the highest lactoferrin/elastase ratio being at periodontitis sites (P<0.001). CONCLUSIONS: These findings imply a change in the relative amounts of elastase and lactoferrin released at different disease level sites, wth an almost 10-fold increase in the proportion of lactoferrin to elastase in periodontitis sites over healthy and gingivitis sites. This variation in the release by PMNs of primary and secondary granule constituents may indicate alterations in PMN function in different disease environments.

Adult↗

PubMed1987

The nutritional role of breast-milk IgA and lactoferrin.

The nutritional enigma concerning the extent to which breast-milk immune proteins are digested has been investigated by measuring the intakes and faecal outputs of IgA and lactoferrin over 7 days in 10 exclusively breast-fed (BF) and 9 formula-fed (FF) fullterm infants at 6 and 12 weeks post-partum. BF outputs (mg/day) greatly exceeded FF values (p less than 0.001): at 6 weeks secretory-IgA BF = 160 +/- 28, FF = 14 +/- 2, lactoferrin BF = 14 +/- 2, FF = 0.9 +/- 0.1; at 12 weeks secretory-IgA BF = 94 +/- 17, FF = 25 +/- 5, lactoferrin BF = 7 +/- 1, FF = 1 +/- 0.3. Secretory-IgA represented 42% and 27% of BF faecal protein at 6 and 12 weeks compared with 6% for FF infants at both ages. BF secretory-IgA outputs were highly correlated with intakes (r = 0.83, p less than 0.001). IgA and lactoferrin outputs and the presence of faecal secretory-IgA fragments in BF and FF infants were influenced by defaecation rate, suggesting that partial degradation occurred in the large intestine. By 6 weeks post-partum only 1% lactoferrin and 17% secretory-IgA intakes appeared in the faeces and 95% breast-milk protein could be regarded as nutritionally available. The elevated BF outputs of IgA and lactoferrin relative to endogenous excretion suggest, however, that breast-milk may still make a considerable contribution to intestinal defence mechanisms after the neonatal period despite the small proportion of daily intake which escapes digestion. The protective action of IgA and lactoferrin may also depend on their site of degradation and the nature of fragments.

Feces↗

PubMedDate not supplied

Supplementation of an adapted formula with bovine lactoferrin. 2. Effects on serum iron, ferritin and zinc levels.

Breast milk provides an excellent supply of most nutrients for newborn infants. Infant formulae should be nutritionally comparable to breast milk especially with regard to critical nutrients like iron and other trace elements. Infant formulae supplemented with various amounts of bovine lactoferrin were given to two groups of infants. These infants were compared with infants receiving unsupplemented formula and breast-fed infants. The effects of these diets on levels of haemoglobin, haematocrit, serum iron, ferritin and zinc were examined for a study period of 150 days. At birth, concentrations of iron, haemoglobin, haematocrit and zinc were comparable in all four feeding groups. The fact that the serum zinc level was not altered by lactoferrin supplementation appears to rule out an in-vivo effect of lactoferrin on zinc nutrition of infants. Ferritin levels of breast-fed infants were significantly higher than in non-supplemented formula-fed infants at day 30 and day 90. This difference was seen only at day 30, when comparing breast-fed infants to lactoferrin-supplemented formula-fed infants. Comparing the infants receiving formulae, the formula supplemented with the higher amount of bovine lactoferrin induced significantly higher serum ferritin levels compared to the unsupplemented formula at day 90 and day 150. These observations favour the idea that lactoferrin may be involved in iron absorption. Since this effect was pronounced only after 90 days, it has to be discussed as to whether this effect is a convincing argument for supplementing infant formulae with bovine lactoferrin.

Animals↗

PubMed2001

Lactoferrin protects against development of hepatitis caused by sensitization of Kupffer cells by lipopolysaccharide.

BALB/c mice were intravenously injected with lipopolysaccharide (LPS) (0.05 microg/g of body weight) 7 days after being primed with zymosan. Recombinant human lactoferrin (250 microg/g of body weight), intravenously administered 1 day before the injection of LPS, significantly lessened the severity of hepatitis, as assessed by levels of serum alanine transaminase compared to those seen when casein was administered. The transient rise of serum tumor necrosis factor alpha (TNF-alpha) after LPS treatment was also significantly lowered by the intravenous administration of lactoferrin, suggesting that the effect of lactoferrin was due to the suppression of TNF-alpha production. The following results indicate that the sites of action of lactoferrin for the suppression of the development of this type of hepatitis are Kupffer cells. Gadolinium chloride, a substance known to eliminate Kupffer cells, administered 1 day before LPS, inhibited the transient rise of TNF-alpha and protected against the development of hepatitis. Kupffer cells isolated from mice intraperitoneally injected with recombinant human lactoferrin became refractory to LPS. The specific interaction of recombinant human lactoferrin with the Kupffer cells was shown by a binding assay, which revealed two types of binding sites on mouse Kupffer cells. Of the two dissociation constants determined in this way, the lower dissociation constant, 0.47 x 10(-6) M, was within the range of the 50% effective doses for the suppression of TNF-alpha production. These results suggest that recombinant human lactoferrin administered to mice suppresses the production of TNF-alpha by Kupffer cells by directly associating with the binding sites on these cells.

Alanine Transaminase↗

PubMed1980

Bactericidal activity of human lactoferrin: sensitivity of a variety of microorganisms.

Lactoferrin is an iron-binding protein that has been detected in secretions that bathe human mucosal tissues. Previous studies have shown that, when this protein is in the iron-free state, it is capable of a direct bactericidal effect on Streptococcus mutans and Vibrio cholerae. The present study demonstrates variable susceptibilities for a variety of different microorganisms. The list of susceptible organisms includes gram-positive and gram-negative microbes, rods and cocci, facultative anaerobes, and aerotolerant anaerobes. Similar morphological and physiological types are represented among the lalctoferrin-resistant bacteria. S. mutans was more resistant to lactoferrin when grown on a sucrose-contaning medium than when it was grown on brain heart infusion broth without added scurose. When a lactoferrin-sensitive, avirulent strain of Streptococcus pneumoniae was passed through mice, the resultant virulent culture became lactoferrin resistant. Since organisms of the same species and even of the same strain (S. pneumoniae) can differ in susceptibility to lactoferrin, it appears that accessibility to the lactoferrin target site may account for differences in susceptibility. It appears that there may be a relation between virulence and resistance to lactoferrin.

Bacteria↗

PubMed1986

Bactericidal effect of lactoferrin on Legionella pneumophila.

Lactoferrin, an iron-binding protein found in mucosal secretions and in specific granules of polymorphonuclear leukocytes, has been shown to be bactericidal for a variety of organisms. In this study, the effect of lactoferrin on Legionella pneumophila was investigated. Purified human apolactoferrin was bactericidal for the Knoxville 1 strain (serogroup 1), with a 4-log decrease in viability within 2 h at 37 degrees C. Killing was dependent on the iron-free state since iron-saturated lactoferrin had no activity. Guinea pig passage of this strain did not affect its sensitivity to lactoferrin. Treatment of the cells with dilutions of the lactoferrin resulted in correspondingly reduced killing. Activity was temperature dependent; there was no loss of viability at 1 or 22 degrees C and slightly enhanced killing at 41 degrees C. Addition of Mg2+ blocked bactericidal activity. In addition, mature human milk, a lactoferrin-containing mucosal secretion, was also bactericidal for L. pneumophila. As demonstrated with the purified lactoferrin, bactericidal activity was lost when the milk was iron saturated.

Animals↗

PubMed2000

Identification of a human lactoferrin-binding protein in Gardnerella vaginalis.

Previous studies have shown that Gardnerella vaginalis can utilize iron-loaded human lactoferrin as a sole source of iron. In this study, G. vaginalis cells were shown to bind digoxigenin (DIG)-labeled human lactoferrin in a dot blot assay. Using the DIG-labeled human lactoferrin, a 120-kDa human lactoferrin-binding protein was detected by Western blot analysis of G. vaginalis proteins. The lactoferrin-binding activity of this protein was found to be heat stable. Competition studies indicated that this binding activity was specific for human lactoferrin. Treatment of G. vaginalis cells with proteases suggested that this protein was surface exposed. An increase in lactoferrin binding by the 120-kDa protein was observed in G. vaginalis cells grown under iron-restrictive conditions, suggesting that this activity may be iron regulated.

Bacterial Proteins↗

PubMed2003

Iron status in mice carrying a targeted disruption of lactoferrin.

Lactoferrin is a member of the transferrin family of iron-binding glycoproteins present in milk, mucosal secretions, and the secondary granules of neutrophils. While several physiological functions have been proposed for lactoferrin, including the regulation of intestinal iron uptake, the exact function of this protein in vivo remains to be established. To directly assess the physiological functions of lactoferrin, we have generated lactoferrin knockout (LFKO(-/-)) mice by homologous gene targeting. LFKO(-/-) mice are viable and fertile, develop normally, and display no overt abnormalities. A comparison of the iron status of suckling offspring from LFKO(-/-) intercrosses and from wild-type (WT) intercrosses showed that lactoferrin is not essential for iron delivery during the postnatal period. Further, analysis of adult mice on a basal or a high-iron diet revealed no differences in transferrin saturation or tissue iron stores between WT and LFKO(-/-) mice on either diet, although the serum iron levels were slightly elevated in LFKO-/- mice on the basal diet. Consistent with the relatively normal iron status, in situ hybridization analysis demonstrated that lactoferrin is not expressed in the postnatal or adult intestine. Collectively, these results support the conclusion that lactoferrin does not play a major role in the regulation of iron homeostasis.

Animals↗