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PubMed2005

Liposomalization of lactoferrin enhanced it's anti-inflammatory effects via oral administration.

It is known that lactoferrin is one of the functional proteins contained in mammalian milk and that it plays an important role in the immune system. In this study, we prepared multi-lamellar liposomal bovine lactoferrin composed of egg yolk phosphatidylcholine and phytosterol for oral delivery, and examined any resulting anti-inflammatory effects. Oral pretreatment of liposomal lactoferrin exhibited more suppressive effects than did non-liposomal lactoferrin on CCl4-induced hepatic injury in rats as well as on lipopolysaccharide-induced TNF-alpha production from mouse peripheral blood mononuclear leukocytes. Further investigation revealed that the liposomalization did not exert influence on the absorbability of lactoferrin to the venous blood or lymph following an intraduodenal administration in rats. Furthermore, there was no significant difference exhibited between the antigenicity of liposomal and non-liposomal lactoferrin, which was measured using the passive cutaneous anaphylaxis reaction following oral sensitization to them in guinea pigs. These results suggest that liposomal lactoferrin might act more effectively than conventional lactoferrin in the intestinal site, which is regarded as an active site of orally administered lactoferrin, although the biological mechanism is not fully understood yet. Consequently we propose that liposomal lactoferrin could be a novel active constituent useful for preventive and therapeutic treatment of inflammatory diseases.

Absorption↗

PubMed2004

Estrogen response element and the promoter context of the human and mouse lactoferrin genes influence estrogen receptor alpha-mediated transactivation activity in mammary gland cells.

A critical step in estrogen action is the recognition of estrogen responsive elements (EREs) by liganded estrogen receptor. Our current studies were designed to determine whether an extended estrogen response element half-site (ERRE) contributes to the differential estrogen responses of the human and mouse lactoferrin overlapping chicken ovalbumin upstream promoter/ERE sequences (estrogen response modules, ERMs) in the context of their natural promoters. Transient transfections of MCF-7 cells show that liganded estrogen receptor alpha (ERalpha) activates transcription of the human lactoferrin ERM fourfold higher than the mouse lactoferrin ERM in the context of their natural promoters. Since the ERRE of the human lactoferrin gene naturally occurs 18 bp upstream from the ERM and is absent in the mouse lactoferrin gene promoter, we created a chimeric mouse lactoferrin CAT reporter, which now encodes the ERRE in the identical location as in the human lactoferrin gene. The addition of the ERRE in the mouse lactoferrin gene rendered this reporter extremely responsive to estrogen stimulation. Using limited protease digestions and electrophoretic mobility shift assays, we showed that the binding and protease sensitivity of ERalpha bound to the mouse ERM with or without the ERRE, differed. Importantly, occupancy of additional nuclear receptors at the ERRE may contribute to ERalpha binding and activation. Furthermore, the presence of ERRE influences the selectivity of coactivators in liganded ERalpha-mediated transcriptional activity. When the receptor is bound to human and mouse plus genes, which contain the ERRE, steroid receptor coactivator (SRC)-2 was preferred, while SRC-1 and SRC-3 coactivators selectively enhanced the mouse lactoferrin gene activity. Moreover, peroxisome proliferator activated receptor-gamma coactivator-1 (PGC-1alpha) and PGC-1-related estrogen receptor coactivator (PERC) robustly increase the transcriptional function of ERalpha in the presence of the ERRE. In conclusion, these data show that the context of the lactoferrin gene influences the ERalpha-mediated transcriptional activity.

Acetyltransferases↗

PubMed2006

Immunolocalization of lactoferrin in healthy and inflamed gingival tissues.

BACKGROUND: It has been reported that lactoferrin prevents biofilm formation and exerts antimicrobial activity. The aim of the present study was to evaluate the cellular source of lactoferrin in healthy and inflamed gingiva. METHODS: Lactoferrin synthesis was examined in relation to disease manifestation in biopsies of the marginal gingiva by immunohistochemistry. The expression of lactoferrin in cell cultures was studied by immunocytochemistry and reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Healthy gingiva demonstrated no immunoreactivity to lactoferrin in epithelial and connective tissue cells. In inflamed specimens, lactoferrin staining was related to inflammatory cells. These results were confirmed by cell cultures of keratinocytes that did not show any immunoreactivity against lactoferrin. No mRNA message for lactoferrin was detected by RT-PCR in keratinocytes. CONCLUSIONS: These data provide evidence that lactoferrin is not synthesized in healthy gingival tissues. Therefore, elevated lactoferrin levels in the crevicular fluid of inflamed tissues originate from invading cells of the inflammatory reaction.

Adult↗

PubMed1989

Gel electrophoresis of human tears reveals various forms of tear lactoferrin.

Lactoferrin is a metal binding protein, which is present in high concentrations in human tears. Little is known concerning the exact molecular shape of lactoferrin in tears. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting experiments showed that this protein is present in multiple forms in tear fluid. SDS-PAGE analysis of human tears under non reducing conditions and pretreatment of tears in sample buffer at room temperature revealed lactoferrin in a major form of 60 kD, a minor form of 64 kD and a third form of 52 kD. Pretreatment of tears at elevated temperatures prior to sample application resulted in the loss of this third form. Disruption of intrachain disulfide bridges prior to SDS-PAGE analysis resulted in a shift in the apparent molecular weight of lactoferrin to 78 kD and 83 kD for the major and minor form, respectively. Chromatography of human tears on ConA-Sepharose as well as enzymatic deglycosylation showed that the difference in molecular weight of the major and minor lactoferrin form was not due to a variation in the carbohydrate side chains. The presence of the minor form could also not be ascribed to iron saturation. Instead we found that addition of iron ions to human tears resulted in a shift of tear lactoferrin to a lower molecular weight species of about 52 kD, coinciding with the third lactoferrin form mentioned above and a small protein band of approximately 57 kD, representing the iron saturated minor lactoferrin form. Similar findings were observed using purified milk lactoferrin. Increasing the temperature prior to sample application or disruption of disulfide bridges dissociated the iron-lactoferrin complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1976

Lactoferrin concentration during involution of the bovine mammary gland.

Electroimmunodiffusion assay was used to quantitate changes in lactoferrin concentration in mammary secretions during involution of the bovine mammary gland. Concentration of lactoferrin began to increase 2 to 4 days after cessation of regular milking and continued to increase linearly at a rate of 1.15 mg/ml per day as a result of increased net synthesis of lactoferrin during the first 14 to 21 days of involution. Maximum lactoferrin concentration (approximately 20 mg/ml) was attained after 3 to 4 wk of involution. These changes represent a 100-fold increase in lactoferrin concentration over that in normal milk. Maximum lactoferrin concentration was variable between cows. In some cows, the concentration of lactoferrin plateaued at less than 10 mg/ml after 10 days of involution. In others, much higher lactoferrin concentrations of 75 to 100 mg/ml were measured. Lactoferrin concentration decreased markedly prior to parturition and onset of lactation. The increase in lactoferrin concentration during mammary gland involution appeared to be related closely to the process of involution.

Animals↗

PubMed1991

Bovine lactoferrin receptors in Staphylococcus aureus isolated from bovine mastitis.

A total of 103 Staphylococcus aureus strains isolated from bovine mastitis were tested for bovine lactoferrin binding in a 125I-labeled protein binding assay. More than 85% of the strains demonstrated high to moderate and a few showed little or no binding. Bovine lactoferrin binding to S. aureus cells was high when grown on blood, nutrient, or proteose-peptone agar, but the binding capacity was low with cells grown on salt rich media, in skim milk, or in broth. The kinetics of 125I-labeled bovine lactoferrin binding required approximately 90 min for complete saturation with optimal interaction in the pH range 4.0 to 7.0. The lactoferrin-staphylococci interaction was specific with a high affinity (association constant, Ka 14 x 10(6) L/mol). Scatchard plot analysis estimated the number of binding sites per cell at 7200 on strain SA-340. Unlabeled bovine lactoferrin effectively displaced the binding of the labeled ligand to strain SA-340 in a dose-dependent manner. Bovine lactoferrin binding was inhibited or displaced by human lactoferrin. Various plasma, connective tissue, or mucosal secretory proteins tested did not inhibit lactoferrin-staphylococci interaction. Bovine lactoferrin binding components on SA-340 were resistant to glycolytic enzymes and moderately susceptible to proteolytic digestion. Two proteins with an estimated molecular weight of approximately 92 and 67 kDa were identified as bovine lactoferrin binding components of S. aureus strain SA-340.

Animals↗

PubMed1989

[Tear lactoferrin in keratoconjunctivitis sicca].

Keratoconjunctivitis sicca is a commonly encountered disease with decreased lacrimal gland activity. There are several tests to determine the lacrimal gland function, but all have limitations in accuracy, sensitivity or technical difficulty. At present, there is no reliable objective test to render a firm diagnosis of dry eye. Lactoferrin is one of the major proteins secreted by the lacrimal gland. Its concentration was found to correlate well to lacrimal gland activity. In this study we tried to evaluate the diagnostic value of lactoferrin measurement in comparison with other tests for keratoconjunctivitis sicca. Tests including the measurement of tear lactoferrin, Schirmer's-1 test, Schirmer's basal test, tear film break-up time, and rose bengal stain of the cornea were done on 60 healthy eyes and 56 eyes with keratoconjunctivitis sicca. The lactoferrin level was measured by a commercially available "Lactoplate" (Eagle Vision, U.S.A.). It is a plate containing gel loaded with rabbit anti-human-lactoferrin antiserum. Tear-moistened filter paper discs containing lactoferrin were placed on the gel. The lactoferrin concentration could be determined by measuring the concentric ring of precipitate after 72 hours incubation at room temperature. The average concentration of lactoferrin was 1.9 +/- 0.51 mg/ml in the normal group and 1.4 +/- 0.93 mg/ml in the keratoconjunctivitis sicca group. They were significantly different from each other (t-test: p less than 0.05). The results of the other 4 tests also showed a significant difference between the normal and keratoconjunctivitis sicca group, but the lactoferrin measurement had the highest specificity among these 5 tests. Because of the technical simplicity of measurement and its high specificity, lactoferrin measurement could be a valuable tool for the early and accurate diagnosis of keratoconjunctivitis sicca.

Adult↗

PubMedDate not supplied

Lactoferrin: a general review.

Lactoferrin is a 703-amino acid glycoprotein originally isolated from milk. Plasma lactoferrin is predominantly neutrophil derived but indications are that it may also be produced by other cells. Lactoferrin in body fluids is found in the iron-free form, the monoferric form and in the diferric form. Three isoforms of lactoferrin have been isolated, ie two with RNase activity (lactoferrin-beta and lactoferrin-gamma) and one without RNase activity (lactoferrin-alpha). Receptors for lactoferrin can be found on intestinal tissue, monocytes/macrophages, neutrophils, lymphocytes, platelets, and on certain bacteria. A wide spectrum of functions are ascribed to lactoferrin. These range from a role in the control of iron availability to immune modulation. More research is necessary however to obtain clarity with regard to the exact mechanism of action of lactoferrin.

Lactoferrin↗

PubMed1998

Reoxygenation injury in a cultured corneal epithelial cell line protected by the uptake of lactoferrin.

PURPOSE: To investigate whether reoxygenation after extended hypoxia causes cellular damage in cultured corneal epithelial cells and to demonstrate the protective effects of lactoferrin. METHODS: Immortalized human corneal epithelial cells (T-HCECs) were cultured to confluence in 96-well culture plates, subjected to stringent hypoxia (1% O2, 5% CO2, 94% N2 at 37 degrees C) for 24 hours, and returned to normoxic conditions (5% CO2, 95% air at 37 degrees C). Cell viability was observed by 1 microM propidium iodide staining 0, 2, 4, and 6 hours after reoxygenation. Inhibition studies were performed after 2 hours' reoxygenation, using 2 mM iron chelator desferrioxamine and 0.2 mg/ml lactoferrin. Confocal immunocytochemistry for human lactoferrin and western blot analysis for lactoferrin-induced ferritin were performed in cultured T-HCECs to demonstrate the internalization of lactoferrin after application. RESULTS: After 2 hours, reoxygenation of T-HCECs after hypoxia produced an increase in cell death that was significantly greater than that observed in normoxic control cells or in cells subjected to hypoxia for the same time span without reoxygenation. The addition of desferrioxamine and lactoferrin at the time of reoxygenation significantly attenuated cellular damage. Confocal immunocytochemistry revealed that lactoferrin is taken into the cytoplasm of T-HCECs as early as 30 minutes after application. This was also demonstrated in western blot analysis by the upregulation of intracellular ferritin at 18 hours by the addition of iron-bound lactoferrin but not by iron-free lactoferrin. CONCLUSION: Reoxygenation is responsible for increased cellular damage after extensive hypoxia, which is attenuated by chelators of free iron in the cytosol, including the major tear protein lactoferrin.

Blotting, Western↗

PubMed1991

Influence of lactoferrin on the function of human polymorphonuclear leukocytes and monocytes.

Polymorphonuclear leukocytes (PMN) exposed to highly purified human lactoferrin (from colostrum) exhibit an increased random motility (at least 2.5-fold) and are primed to produce more superoxide [12.1 +/- 1.2 nmol O2-/min/10(6) PMN preincubated with lactoferrin (0.5 mg/ml) against 6.4 +/- 2.3 with cells without lactoferrin after FMLP stimulation]. The action of lactoferrin seemed to be specific, because it could be abolished by simultaneous addition of antilactoferrin antibody. Addition of transferrin and iron salts to PMN was without effect. Between iron-poor and iron-saturated lactoferrin there was no difference in influence on PMN function except for a higher FMLP stimulated superoxide production by iron-saturated lactoferrin. Aggregation, degranulation (beta-glucuronidase, lysozyme), and bacterial killing were not influenced by lactoferrin. Incubation of monocytes and monocyte-derived macrophages with lactoferrin did not alter their motility or their superoxide production rates. Our findings indicate that PMN become more effective after exposure to lactoferrin by having a greater motility and producing superoxide at a faster rate.

Cell Aggregation↗

PubMed1994

P-selectin-dependent leukocyte recruitment and intestinal mucosal injury induced by lactoferrin.

Plasma concentrations of lactoferrin relevant to an inflammatory response are known to elicit leukocyte-endothelial cell adhesion in mesenteric venules. The objectives of this study were (1) to determine whether exogenously administered lactoferrin causes microvascular and mucosal injury in rat intestine and (2) to assess the contribution of adherent leukocytes to a lactoferrin-mediated injury process. Mucosal myeloperoxidase (MPO) activity and vascular protein clearance were monitored in the distal intestine of male Sprague-Dawley rats. Macroscopic erosive lesions of the mucosa and increases in mucosal MPO and intestinal vascular protein were observed 2 h following the lactoferrin infusion, results consistent with granulocyte accumulation and microvascular protein leakage. These lactoferrin-induced alterations were significantly attenuated in animals pretreated with a monoclonal antibody (mAb) directed against P-selectin but not by an E-selectin-specific mAb. In another series of experiments, leukocyte adherence/emigration and leakage of fluorescein isothiocyanate (FITC)-labeled albumin were measured in rat mesenteric venules using intravital video microscopy. Lactoferrin elicited increases in both leukocyte adhesion/emigration and albumin extravasation, which were attenuated by mAbs directed against P-selectin but not E-selectin. These observations indicate that (1) the lactoferrin released by activated neutrophils may lead to significant microvascular and mucosal injury or dysfunction and (2) the lactoferrin-induced injury is related to P-selectin-mediated adhesion of leukocytes to microvascular endothelium. Our results raise the possibility that neutrophil-derived lactoferrin contributes to the inflammatory response by promoting further granulocyte accumulation and activation and that mAbs to P-selectin may be therapeutically beneficial in inflammatory disorders.

Animals↗

PubMed1997

Characterization of human lactoferrin produced in the baculovirus expression system.

Lactoferrin, an iron-binding 80-kDa glycoprotein, is a major component of human milk whose structure is now well defined. The binding site of lactoferrin to the membrane receptor of lymphocyte has been located in the region 4-52, but the amino acids directly involved in the interaction have not been identified yet. To gain further insights into the structure-function relationships of the lactoferrin binding site, we first expressed the cDNA encoding human lactoferrin in the lepidoptera Spodoptera frugiperda cells (Sf9) using a recombinant baculovirus. The selected transformant secreted and N-glycosylated protein of 78 kDa which was immunoprecipitated by specific anti-lactoferrin antibodies. To confirm the structure and the function of the recombinant lactoferrin, the protein was purified by ion-exchange chromatography and its physical, biochemical, and biological properties were compared with those of the native protein. In particular, the N-terminal amino acid sequence and the iron-binding stability as a function of pH, of both proteins, were identical. The main difference concerns the glycosylation which leads to glycans of lower molecular masses as detected by the electrophoretic mobility of lactoferrin after N-glycosidase F treatment and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. Despite the different glycosylation features, the recombinant lactoferrin retained the binding property to the Jurkat human lymphoblastic T-cell line of the native lactoferrin. On the basis of these analyses, production of protein mutants generated by site-directed mutagenesis is now in process.

Animals↗

PubMed1994

Lactoferrin and the inflammatory response.

Polyclonal antibodies were prepared to purified breast milk lactoferrin and used in an ELISA to measure plasma concentrations in investigations of various aspects of the inflammatory response. They were also used, in situ, to evaluate granulocyte lactoferrin content in disease states. The first series of studies addressed the putative role of lactoferrin in the pathogenesis of the hypoferremic, hyperferritinemic response to acute inflammation. Dissociation between the lactoferrin response and the iron related changes in rheumatoid arthritis and after alpha-interferon administration suggested that the relationship observed in acute and chronic bacterial infection may reflect coincidental effects of inflammatory cytokines. That lactoferrin does not mediate the inflammatory hypoferremic response was established by the finding that bone marrow transplant recipients, post-myeloablation, developed a hypoferremic response during septic episodes despite virtually undetectable plasma lactoferrin concentrations. The second series of investigations employed the plasma lactoferrin concentration as an index of granulocyte activation and function in a number of inflammatory conditions. Markedly increased initial plasma concentrations in acute pneumonia reflecting profound intravascular granulocyte activation were documented to predict sepsis related mortality. Plasma and granulocyte lactoferrin studies established that viral infection is associated with an acquired granulocyte lactoferrin deficiency. Plasma measurements indicated that asthmatics, even when clinically asymptomatic, have evidence of persistent granulocyte activation.

Animals↗

PubMed1986

Plasma lactoferrin in patients with neutropenia.

This study examines the role of plasma lactoferrin in the assessment of neutropenia. In particular, we have studied lactoferrin as an inhibitor of granulopoiesis and as an indicator of the size of the total blood granulocyte pool (TBGP). Plasma lactoferrin concentration was determined in a heterogeneous group of 30 patients with neutropenia. Serial plasma lactoferrin levels in a patient with cyclic neutropenia correlated with the cycles of the neutrophil count. Patients with splenomegaly had a grossly elevated lactoferrin:neutrophil ratio. Most chronic idiopathic neutropenia patients had no real clinical problems and a normal plasma lactoferrin level. The results provide further evidence to support the concept that plasma lactoferrin indicates the size of the TBGP and the lactoferrin: neutrophil ratio indicates the degree of granulocyte margination. There was no evidence to suggest that lactoferrin acting as a feedback inhibitor of granulopoiesis caused neutropenia in these patients.

Agranulocytosis↗

PubMed1982

Lactoferrin, lysozyme, and beta 2-microglobulin levels in cerebrospinal fluid: differential indices of CNS inflammation.

The CSF levels of lactoferrin, lysozyme, and beta 2-microglobulin (beta 2 mu) were measured in patients with evident, probable, or possible inflammatory CNS reactions and compared to those found in neurologically apparently healthy patients. Patients with viral CNS infections had significantly raised beta 2 mu and lysozyme levels but normal lactoferrin levels, indicating a local activation of lymphocytes and monocytes but not of granulocytes. Patients with bacterial CNS infections had significantly raised levels of all three cell markers, but the increase of lysozyme and lactoferrin was relatively more pronounced than that of beta 2 mu, indicating that the inflammatory response to bacterial agents is dominated by monocytes and granulocytes. Patients with primary or secondary malignant brain tumors were characterized by a moderate increase of beta 2 mu and a considerable increase in both lysozyme and lactoferrin, i.e., the same protein pattern as observed in bacterial CNS infection. The lysozyme levels were moderately increased in half the patients with benign cerebral tumors while the levels of beta 2 mu and lactoferrin were normal, indicating that benign and malignant brain tumors induce different local inflammatory CNS reactions. Half the patients with pituitary gland adenoma had elevated beta 2 mu and lysozyme levels but normal lactoferrin levels, suggesting that immunological mechanisms are associated with the adenoma development. Patients with MS had moderately but significantly raised CSF levels of beta 2 mu and lysozyme and a third of them also had raised levels of lactoferrin, a protein pattern suggesting a low-active inflammatory process in CNS involving mononuclears and granulocytes. A similar protein pattern was found in Guillain-Barré syndrome. In cerebrosarcoidosis we noted considerably increased lysozyme and beta 2 mu but normal lactoferrin levels, consistent with the idea that the sarcoid granuloma mass is dominated by monocytic inflammatory cells. The data obtained indicate a clinical value of lactoferrin, lysozyme, and beta 2 mu as differential indices of inflammatory cell reactions taking place in various CNS processes.

Adult↗

PubMed1996

Structure and biological actions of lactoferrin.

Lactoferrin is an iron-binding glycoprotein of the transferrin family, first isolated from milk but also found in most exocrine secretions as well as in the secondary granules of neutrophils. The many reports on its antimicrobial and antiinflammatory activity in vitro identify lactoferrin as important in host defense against infection and excessive inflammation. Most if not all lactoferrin actions are mediated through iron sequestration and/or interaction with a large variety of ligands including microbial cell wall components and cellular receptors, through its highly positively charged N-terminus. Lactoferrin exerts its effects on glandular epithelia, secretions, mucosal surfaces as well as in the interstitium and vascular compartments where it has been postulated to participate in iron metabolism, disease defense, and modulation of inflammatory and immune responses. A need to understand the diverse biological actions of lactoferrin and the prospect of a wide variety of potential applications in human health care have stimulated studies of the relation between lactoferrin structure and function, the regulation of lactoferrin secretion and development of large scale production of recombinant human lactoferrin (hLf). This review provides a synthesis of our current understanding of lactoferrin. Space limitations have led us to refer to review articles whenever possible; the reader is advised to use these articles for access to the primary experimental literature.

Anti-Infective Agents↗

PubMed1992

Different profiles of induced cotton effects of human and bovine lactoferrin by cibacron blue F3GA binding.

1. The properties of complex formation of lactoferrin with Cibacron Blue F3GA dye have been studied by circular dichroic spectral analyses. The Cotton effects were induced by the interaction of lactoferrin with the dye and occurred in the wavelength range from 300 to 450 nm. 2. The patterns of changes in circular dichroic spectra of lactoferrin induced by the dye were different in bovine and human lactoferrin. 3. Iron ions bound to lactoferrin affected the profiles of induced Cotton effects in human lactoferrin but not in bovine lactoferrin. 4. While the dye bound co-operatively to human apo-lactoferrin, such co-operativeness was not observed in iron-saturated human lactoferrin.

Animals↗

PubMed2006

Lactoferrin expression in the canine uterus during the estrous cycle and with pyometra.

The expression of lactoferrin, a non-specific antimicrobial defence, in the canine uterus during the normal estrous cycle and in bitches with pyometra was examined. Using polymerase chain reaction analysis, lactoferrin gene transcripts were detected in the endometrium at all stages of the estrous cycle, with the highest levels in estrus. In normal bitches, endometrial lactoferrin mRNA increased from proestrus to estrus (P<0.05). Thereafter, it dramatically decreased from estrus to Day 10 of diestrus (P<0.05), and stayed low at Day 35 of diestrus and anestrus; this was consistent with blood estrogen concentrations. Levels of lactoferrin mRNA were higher in bitches with pyometra than in normal diestrus (P<0.05). With immunohistochemistry, distinct staining of lactoferrin was detected in the luminal and glandular epithelial cells of the endometrium at proestrus and estrus, but little staining was detected at Day 10 of diestrus. At Day 35 of diestrus and anestrus, a partial and weak reaction was present in the same region. In bitches with pyometra, the glandular epithelial cells and many cells in the uterine stroma were strongly stained. Staining cells in the stroma were morphologically similar to neutrophils. No lactoferrin staining was seen in the uterine stromal cells or myometrium in any section. These results suggest that, in the canine uterus, lactoferrin expression is related to the blood concentration of estrogen, and that the dramatic reduction in lactoferrin observed at the early stage of diestrus may impair antimicrobial defense. Also, enhanced expression of lactoferrin mRNA in the endometrium with pyometra may be associated with neutrophil invasion into the uterus to combat the infection.

Amino Acid Sequence↗