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LACTOFFERIN

LACTOFERRIN is a naturally-occurring iron-binding protein, and is the second most abundant protein in human colostrum, the first milk secreted at the termination of pregnancy. Lactoferrin is undoubtedly one of the most significant nutritional components of milk, comprising more than 20% of the total colostral protein. Additionally, small amounts of lactoferrin are also found in saliva, tears, and mucous secretions.

Lactoferrin has been shown to influence the composition of the intestinal flora of infants, and in the development of healthy and functional immune systems. Its systemic concentration is down regulated during pregnancy, presumably to allow the maternal immune system to not reject the fetus. Lactoferrin levels are elevated in the mother at term in pregnancy to restore maternal immune responses. Thus, lactoferrin has immune system benefits.

Lactoferrin has been shown to be involved in iron metabolism and biochemical processes in Lymphocytes, white blood cells formed in the lymphoid tissues. White blood cells help fight off infections. Iron metaboIism is an important mechanism by which both animals and plants moderate their growth.

Lactoferrin greatly impacts bacterial growth by regulating iron. It is widely considered to be an important component of the host defense against microbial infections. In order to grow and multiply, most bacteria need Iron. Lactoferrin, with its amazing ability to bind iron. absorbs excess iron in the body, nutritionally depriving the bacteria of iron.

Individuals experiencing dysbiosis probably have a general reduction in Gastrointestinal (Gl) immune function, leaving these individuals more prone to GI disturbances. They are unable to monitor or respond to inappropriate microbial growth. Current evidence suggests this sort of immunosuppresion can involve a decrease in lactoferrin production.


SELECTED ABSTRACTS

1. Regulatory Iron-Binding Proteins And Self-Reactive Antibodies In Pregnancy And In AIDS: A Conceptual Model Of Immune System Pathology And Therapeutic Approaches. Earl M. Ettienne, Ph.D.

An hypothesis is advanced where HIV disease, and concomitant Acquired Immune Deficiency Syndrome (AIDS), is shown to have a distinct similarity in the primary immune suppression, to the cellular and humoral immune-system modulation by iron-binding glycoproteins encountered during pregnancy. A key comparison is drawn between the suppression of the HlV-infected, immune system and the down-regulation of the immune system in pregnancy by a T-cell-derived Iymphokine, placental isoferritin (PLF), which blocks CD4+ T-helper responses to fetal antigen through a CD8+-dependent suppression.

The observations of elevated concentrations of this suppressor Iymphokine in the serum of HlV positive individuals is matched to depressed concentrations of an antagonist Iymphokine, lactoferrin (LF), which acts at term in pregnancy to restore maternal immune responses. These observations and the proposed model suggests new conceptual approaches towards understanding HIV disease and potentially new therapeutic avenues utilizing natural and synthetic inducers and inhibitors of these immune system modulating Iymphokines. Int'l Journal of Biosocial & Medical Research. 1995. 14 (1).


2. Immunostimulatory Activity Of Lactotransferrin And Maturation of CD4-CD8- Murine Thymocytes. Michal Zimecki, Joel Mazurier, Michal Machnicki, Zbigniew Wieczorek, Jean Montreuil and Genevieve Spik.

Summary: Human milk lactotransferrin at a concentration ranging from 1 to 10 mcg/ml stimulated up to 5 times the humoral immune response to sheep red blood cells, expressed as the number of plaque-forming cells, when injected into mice, enhanced the immune response to sheep red blood cells to the same extent as IL-1.

In vitro studies showed that CD4- CD8- thymocytes incubated with lactotransferrin and added to the splenocyte cultures increased the immune response to sheep red blood cells. Flow cytometry analysis studies indicated that, after an overnight incubation with human lactotransferrin, CD4- CD8 thymocytes acquired the CD4 antigen characteristic for the helper cell phenotype. Taken together, these results suggest that lactotransferrin stimulates the immune response by a process which involves the promotion of T cell differentiation. Immunology Letters, 30 (1991) 119-124.


3. Identification Of The Bactericidal Domain Of Lactoferrin Wayne Bellamy, Mitsunori Takase, Koji Yamauchi, Hiroyuki Wakabayashi, Kouzou Kawase and Mamoru Tomita, Nutritional Science Laboratory, Morinaga Milk industry Company Limited, Zama City (Japan).

We report the existence of a previously unknown antimicrobial domain near the N-terminus of lactoferrin in a region distinct from its iron-binding sites. A single active peptide representing this domain was isolated following gastric pepsin cleavage of human lactoferrin, and bovine lactoferrin, and sequenced by automated Edman degradation.

The antimicrobial sequence was found to consist mainly of a loop of 19 amino acid residues formed by a disulfide bond between cysteine residues 20 and 37 of human lactoferrin, or 19 and 36 of bovine lactoferrin. Synthetic analogs of this region similarly exhibited potent antibacterial properties. The active peptides of bovine lactoferrin was more potent than that of human lactoferrin having effectiveness against various Gram-negative and Gram-positive bacteria at concentrations between 0.3 ,uM and 3.0 uM, depending on the target strain. The effect of the isolated domain was lethal, causing a rapid loss of colony-forming capability. Our studies suggest this domain is the structural region responsible for the bactericidal properties of lactoferrin. Biochimica et Biophysica Acta, 1121 (1992) 131-136.


4. Proposed Mechanisms for the Involvement of Lactoferrin in the Hydrolysis of Nucleic Acids. Xiao-Yan Zhao and T. William Hutchens. Protein Structure Laboratory USDA/ARS Children `s Nutrition Research Center.

Abstract: Lactoferrin has recently been proposed to have ribonuclease activity in the absence of bound iron. We and others have demonstrated previously that lactoferrin interacts with DNA and will bind a number of transition metal ions via surface-exposed histidyl residues. In the present study, we investigated the possibility that surface-bound copper ions on lactoferrin may catalyze the production of active oxygen species responsible for the hydrolysis of nucleic acids.

Purified lactoferrin (apo- and holo-forms) was incubated with CuCl2 in solution to obtain lactoferrin with surface binding sites saturated by Cu (II) ions. The lactoferrin-Cu (II) complex was purified by Bio-Gel P-6 chromatography columns and tested for hydrolytic activity against DNA and RNA as analyzed by agarose gel electrophoresis. Incubation of lactoferrin-Cu(II) complexes with supercoiled plasmid Bluescript II SK DNA led to the rapid formation of relaxed open circular or linear forms DNA characterized by changed electrophoretic mobility. Lactoferrin with bound Cu (II) also caused extensive degradation of yeast tRNA molecules in the presences of hydrogen peroxide. Covalent modification of surface-exposed histidyl residues by carboxyethylation with diethylpyrocarbonate abolished the lactoferrin-associated hydrolytic activity.

These results indicate that lactoferrin-bound Cu(II) can indeed facilitate the hydrolysis of DNA and RNA molecules. Copper-binding sites on lactoferrin appear to serve as centers for repeated production of hydroxyl radicals via a Fenton-type Haber-Weiss reaction. Enhanced nuclease activity associated with elevated local concentrations of lactoferrin would promote microbial degradation. Lactoferrin: Structure and Function. Edited by T.W. Hutchens et al., Plenum Press, New York, 1994.


5. Lactoferrin Levels in Pure Pancreatic Secretion of Chronic Pancreatitis. Tympner F; Gutmann W.

Abstract: As compared to 20 controls, 14 patients with chronic pancreatitis showed a significantly higher lactoferrin level in pure pancreatic secretion. The determination of lactoferrin levels in pure pancreatic secretion is an important parameter in the diagnosis of chronic pancreatitis. Zeitschrift fur Gastroenterologie, 1979 Dec, 17 (12):858-61.


6. Lactoferrin Contains Structural Motifs of Ribonuclease. A. Sharada Devi, M.R. Das, M. Pandt, Centre for Cellular and Molecular Biology, Uppal road, Hydrabad 500 007, India.

Abstract: A high molecular weight ribonuclease isolated from human milk (hmRNAase) shares identical immunological, physical, structure features and considerable sequence homology with human lactoferrin; and it has been demostrated to be an isoform of lactoferrin. We have analyzed the sequence data of lactoferrin looking for the existence of specific features corresponding to the consensus sequence of pyrimidine-specific ribonucleases.

The analysis was done by comparing sequence features with respect to elements which are, in principle, responsible for RNAase activity. This revealed the existence of a ribonuclease-signature pattem in lactoferrin. Further analysis of X-ray data together with molecular modeling studies have revealed close similarities between the spatial geometry of the constituent groups of the active site of pyrimidine-specific ribonucleases and the corresponding groups comprising the potential active sites of lactoferrin. Our results provide the strong structural basis for the existence of ribonuclease activity in lactoferrin. Biochimica et Biophysica Acta 1205 (1994) 275-281.


7. Synergistic Effect of Human Lactoferrin And Recombinant Murine Interferon On Disease Progession in Mice Infected With The Polycythemia-Inducing Strain Ff The Friend Virus Complex. Li Lu, Rong-Nian Shen, Shang Zhen Zhou, Carolyn Srivastava, Maureen Harrington, Keisuke Miyazawa, Bo Wu, Zhong Hua Lin, Sandra Ruseetti and Hal E. Broxmeyer.

Abstract: Mice infected with the polycythemia-inducing strain of the Friend virus complex (FVC-P) have been used as a leukemic mouse model. In the present study, purified iron-saturated human lactoferrin (LF) and recombinant murine (rmu) interferon-y (IFN-y), alone or in combination, were used to influence disease progression in virally infected mice. DBA/2 mice were injected i.v. with FVC-P, and were treated s.c. with 00 micrograms LF at day 7, and/or rmuIFN-y at 5 x 10(4) units/day for 3 days beginning at day 6 after viral inoculation. The mice were killed and spleen extracts were assessed for spleen focus forming virus (SFFV) titers by spleen focus forming (SFFU) assay, SFFV mRNA and genomic DNA expression, and natural killer (NK) cell activity.

Treatment with LF or rmuIFN-y alone had little or no effect on SFFU numbers or SFFV mRNA or genomic DNA expression. However, dramatically decreased SFFV titers and levels of SFFV mRNA and genomic DNA were observed in mice treated with the combination of LF and rmuIFN-. NK cell activity decreased by FVC-P was returned to normal levels by LF and rmulFN-y. The combined treatment also enhanced the survival rates of FVC-P-infected mice. The result suggest synergistic suppresive effects of LF with rmulFN-y on disease progression in FVC-P-infected mice. This information might be of significance as a potential therapy for patients with leukemia and those infected with retroviruses. International Journal of Hemotology, 54 (1991) 117-124.


8. Lactoferrin Promotes Nerve Growth Factor Synthesis/Secretion In Mouse Fibroblast L-M cells. Shinoda I; Takase M; Fukuwatari Y; Shimamura S.

Abstract: Fibroblast cells are known to have an ability to synthesize and secrete nerve growth factor (NGF). To investigate the mechanism of action of the iron-binding protein, lactoferrin (Lf), on cultured animal cells, the effect of bovine Lf (bLf) on NGF synthesis/secretion in mouse fibroblast cells was examined. Both apo- and holo-bLf induced an increase in NGF content in the cell-conditioned medium(CM) of mouse L-M cells, a line derived from L929 fibroblast cells, with similar effectiveness. The increase in NGF content in the CM of L-M cells cultured with bLf was not dependent on the induction of increase in cell numbers, but was due to induction of de novo synthesis of NGF in individual cells by bLf.

Human Lf(hLf) also increased NGF content. However, apo- and holo-bovine transferrin Tf) failed to stimulate the NGF synthesis. The time-dependent induction of NGF in L-M cells by bLf was different from that induced by basic fibroblast growth factor (bFGF) and bLf showed an additive effect with bFGF. These results suggest that the induction of NGF synthesis depends on a mechanism different from iron transport or bFGF. Advances in Experimental Medicine and Biology, 1994, 357:279-85.


9. Anti-lactoferrin Auto-antibodies Associated With HIV Infection. Deter MC; Follezou JY; Picard O; Damais C.

Abstract: Sera from 85 HlV-infected patients were tested for the presence of antilactoferrin antibodies (anti-LF Abs) by specific ELISA. Fifty-seven sera were found positive, including sera from asymptomatic (18/28, 64.3%, mean O.D.: 0.27 +/- 0.05) and symptomatic patients (39/57,68.4%, mean O.D.: 0.82 +/- 0.15). In the control group, only one out of 26 normal donors show any reactivity (mean O.D.: 0.06 +/- 0.01). None of the tested patients had clinical evidence of vasculitis, the previous reported antilactoferrin-associated pathology and if, in both groups, a similar frequency of anti-LF Abs was found, the autoantibody level was significantly higher among the symptomatic patients (p 0.01). However, correlation was found neither with polymorphonuclear cell counts nor with the level of circulating lactoferrin. The characterization and the clinical significance of the autoantibodies are under investigation. Comptes Rendus de L Academie des Sciences. Serie III, Sciences de la Vie, 1994 Jul, 317 (7):675-8.


10. The Role Of Lactoferrin As An Anti-Inflammatory Molecule. Britigan BE; Serod JS; Cohen MS.

Abstract: The formation of hydroxyl radical via the iron catalyzed Haber-Weiss reaction has been implicated in phagocyte-mediated microbicidal activity and inflammatory tissue injury. The fact that neutrophils contain lactoferrin and mononuclear phagocytes have the capacity to acquire exogenous iron has suggested that iron bound to lactoferrin may influence the nature of free radical products generated by these cells. Over the years the iron-lactoferrin complex has been heralded as both a promoter and inhibitor of hydroxyl radical formation. This manuscript is intended to provide an overview of work performed to date related to this controversy and to present results of a number of preliminary studies which shed further light on the role of lactoferrin in inflammation. Advances in Experimental Medicine and Biology, 1994, 357:143-56.


11. Suggested Models Of Ecotaxopathy In Lymphoreticular Malignancy. A Role For Iron-Binding Proteins In The Control Of Lymphoid Cell Migration. de Sousa M; Smithyman A; Tan C.

Abstract: In the present paper we apply the "ecotaxis hypothesis" to the analysis of Iymphocyte distribution in Hodgkin's disease and other forms of Iymphoid malignancy. The results lead us to consider the possibility that metal-binding proteins, namely ferritin, transferrin and lactoferrin, play a role in Iymphocyte ecotaxopathy. It is suggested that in Hodgkin's disease, a failure of Iymph node and spleen monocytes to handle iron normally could explain most of the hematologic, immunologic, pathologic, and epidemiologic features of the disease. American Journal of Pathology, 1978 Feb, 90(2):497-520.


12. Lactoferrin In Pure Pancreatic Juice In Chronic Pancreatitis. Hayakawa T; Harada H; Noda A; Kondo T.

Abstract: To investigate the role of lactoferrin in intraductal protein precipitates in chronic pancreatitis, lactoferrin was measured in pure pancreatic juice collected by endoscopic retrograde pancreatic cannulation using a sensitive and specific radioimmunoassay. Significant gradual increase in the lactoferrin concentration and output was observed in chronic pancreatitis (mean +/- SE = 1.13 +/- 0.04 microgram/ml, 1.61 +/-0.44 microgram/min for five controls; 4.73 +/- 0.70 microgram/ml, 14.1 +/- 2.86 micrograms/min for 15 patients with noncalcified mild chronic pancreatitis; 23.6 +/- 4.7 micrograms/ml, 28.4 +/- U.
American Journal of Gastroenterology, 1983 Apr, 78(4):222-4.


13. Treatment Of Diarrhea In Human Immunodeficiency Virus-Infected Patients With Immunoglobulins From Bovine Colostrum. Rump JA; Arndt R; Arnold A; Benick C; Dichtelmuller H; Franke M; Helm EB; Jager H; Kampmann B; Kolb P; etal.

Abstract: Diarrhea and weight loss are found in more than 50% of patients with the acquired immunodeficiency syndrome (AIDS). In some patients the symptoms can be very severe, leading to death even in the absence of opportunistic infections. In 30% of these patients, enteric pathogens cannot be identified, and approximately only half of the identifiable aetiologic agents of diarrhea in patients infected with the human immunodeficiency virus (HIV) were treatable with antibiotics. Immunoglobulins from bovine colostrum (Lactobin, Biotest, Dreieich, FRG) contain high titers of antibodies against a wide range of bacterial, viral and protozoal pathogens as well as against various bacterial toxins.

Lactobin (LIG) is quite resistant to 24-h incubation with gastric juice. In a multi-center pilot study 37 immunodeficiency patients with chronic diarrhea [29 HlV-infected patients, 2 patients with common variable immunodeficiency (CVID), one unidentified immunodeficiency, five patients with graft versus host disease (GvHD) following bone marrow transplantation] were treated with oral LIG (10 g/day for 10 days).

Good therapeutic effects were observed. Out of 31 treatment periods in 29 HlV-infected patients 21 gave good results leading to transient (10 days) or long-lasting (more than 4 weeks) normalization of the stool frequency. The mean daily stool frequency decreased from 7.4 to 2.2 at the end of the treatment. Eight HlV-infected patients showed no response. The diarrhea recurred in 12 patients within 4 weeks (32.4%), while 19 patients were free of diarrhea for at least 4 weeks (51.3%). In 5 patients intestinal cryptosporidiosis disappeared following oral LIG treatment. LIG treatment was also beneficial in 4 out of 5 GvHD patients. Clinical Investigator, 1992 Jul, 70(7).588 94.


14. Suggested Models Of Ecotaxopathy In Lymphoreticular Malignancy. A Role For Iron-Binding Proteins In The Control Of Lymphoid Cell Migration. de Sousa M; Smithyman A; Tan C.

Abstract: In the present paper we apply the "ecotaxis hypothesis" to the analysis of Iymphocyte distribution in Hodgkin's disease and other forms of Iymphoid malignancy. The results lead us to consider the possibility that metal-binding proteins, namely ferritin, transferrin and lactoferrin, play a role in Iymphocyte ecotaxopathy. It is suggested that in Hodgkin's disease, a failure of Iymph node and spleen monocytes to handle iron normally could explain most of the hematologic, immunologic, pathologic, and epidemiologic features of the disease. American Journal of Pathology, 1978 Feb, 90(2):497-520.


15. Lactoferrin In Pure Pancreatic Juice In Chronic Pancreatitis. Hayakawa T; Harada H; Noda A; Kondo T.

Abstract: To investigate the role of lactoferrin in intraductal protein precipitates in chronic pancreatitis, lactoferrin was measured in pure pancreatic juice collected by endoscopic retrograde pancreatic cannulation using a sensitive and specific radioimmunoassay. Significant gradual increase in the lactoferrin concentration and output was observed in chronic pancreatitis (mean +/- SE = 1.13 +/- 0.04 microgram/ml, 1.61 +/-0.44 microgram/min for five controls; 4.73 +/- 0.70 microgram/ml, 14.1 +/- 2.86 micrograms/min for 15 patients with noncalcified mild chronic pancreatitis; 23.6 +/- 4.7 micrograms/ml, 28.4 +/- U. American Journal of Gastroenterology, 1983 Apr, 78(4):222-4.


16. Treatment Of diarrhea In Human Immunodeficiency Virus-Infected Patients With Immunoglobulins From Bovine Colostrum. Rump JA; Arndt R; Arnold A; Benick C; Dichtelmuller H; Franke M; Helm EB; Jager H; Kampmann B; Kolb P; etal.

Abstract: Diarrhea and weight loss are found in more than 50% of patients with the acquired immunodeficiency syndrome (AIDS). In some patients the symptoms can be very severe, leading to death even in the absence of opportunistic infections. In 30% of these patients, enteric pathogens cannot be identified, and approximately only half of the identifiable aetiologic agents of diarrhea in patients infected with the human immunodeficiency virus (HIV) were treatable with antibiotics. Immunoglobulins from bovine colostrum (Lactobin, Biotest, Dreieich, FRG) contain high titers of antibodies against a wide range of bacterial, viral and protozoal pathogens as well as against various bacterial toxins.

Lactobin (LIG) is quite resistant to 24-h incubation with gastric juice. In a multi-center pilot study 37 immunodeficiency patients with chronic diarrhea [29 HlV-infected patients, 2 patients with common variable immunodeficiency (CVID), one unidentified immunodeficiency, five patients with graft versus host disease (GvHD) following bone marrow transplantation] were treated with oral LIG (10 g/day for 10 days). Good therapeutic effects were observed. Out of 31 treatment periods in 29 HlV-infected patients 21 gave good results leading to transient (10 days) or long-lasting (more than 4 weeks) normalization of the stool frequency. The mean daily stool frequency decreased from 7.4 to 2.2 at the end of the treatment. Eight HlV-infected patients showed no response. The diarrhea recurred in 12 patients within 4 weeks (32.4%), while 19 patients were free of diarrhea for at least 4 weeks (51.3%). In 5 patients intestinal cryptosporidiosis disappeared following oral LIG treatment. LIG treatment was also beneficial in 4 out of 5 GvHD patients. Clinical Investigator, 1992 Jul, 70(7).588 94.


17. In Vitro Screening Of Therapeutic Agents Against Cryptosporidium: Hyperimmune Cow Colostrum Is Highly Inhibitory. Flanigan T; Marshall R; Redman D; Kaetzel C; Ungar B.

Abstract: An in vitro model of Cryptosporidium parvum infection was developed utilizing an adherent human intestinal epithelial cell line HT29.74. The efficacy of potential immunologic therapy in the form of Cryptosporidium-specific hyperimmune bovine colostrum was evaluated for the ability to inhibit in vitro infection. Oocysts were purified from stool of chronically infected AIDS patients. Hyperirnmune colostrum obtained from cows immunized with Cryptosporidium and nonimmune conventional colostrum were evaluated. Oocysts (10(5)-10(6)) were pre-incubated with either hyperirnmune colostrum, conventional colostrum, or saline as control, for 15 min at room temperature than applied to a 70% confluent monolayer of HT29.74 cells.

Cryptosporidium schizonts were identified and counted per 1,000 HT29.74 cells under oil immersion after 24 hours. In the presence of hyperimmune colostrum, parasite infection was inhibited by 82% (p less than 0.001), and in the presence of conventional colostrum, infection was inhibited by 67% (p less than 0.001). Treatment with the soluble fraction of hyperimmune colostrum resulted in 69% inhibition (p less than 0.001) compared to the soluble fraction of conventional colostrum which resulted in only 17% inhibition (p=NS) . In vitro Cryptosporidium parvum infection of the differentiated human enterocyte cell line HT29.74 is a viable method for screening immunologic therapies. Hyperimmune bovine colostrum was highly inhibitory of Cryptosporidium infection in vitro and its soluble fraction remained significantly inhibitory while the soluble fraction of conventional colostrum did not. Journal of Protozoology, 1991 Nov-Dec, 38(6):2255-2275.


18. Filtration And Local Synthesis Of Lacrimal Proteins In Acquired Immunodeficiency Syndrome. Meillet D; Hoang PL; Unanue F; Kapel N; Dmert MC; Rousselie; Galli A; Galli J.

Abstract: In AIDS the onset of the ocular dry syndrome, characterized by lacrimal hyposecretion and deterioration of the corneal and conjunctival epithelium, generally accompanies the clinical aggravation of immunodepression. The study of serum and lacrimal proteins contributes to our knowledge of the pathophysiology of this syndrome. The lacrimal clearance of albumin indicates changes in the permeability of the haemato-lacrimal and conjunctival barrier. Lacrimal monomeric IgA and IgG are mainly of plasmatic origin, while polymeric IgA and IgM are synthesized in situ. The concentrations of these analytes thus reflect ocular humoral immune status. They show a strong humoral protein response in patients with cytomegalovirus retinitis. Lacrimal concentrations of lactoferrin and Iysozyme were found to be significantly decreased in AIDS patients with ocular dryness, reflecting a decrease in the secretory activity of the lacrimal gland. Moreover, ocular Iympho-plasmocyte infiltration was observed in several patients, with an increase in acrimal beta 2-microglobulin concentrations. These various lacrimal proteins could be good markers of the ocular dry syndrome in AIDS. European Journal of Clinical Chemistry and Clinical Biochemistry, 1992 Jun, 30(6):3123.


19.The Fungicidal Effect Of Human Lactoferrin On Candida Albicans And Candida Krusei. Nikawa H; Samaranayake LP; Tenovuo J; Pang KM; Hamada T.

Abstract: Five oral isolates each of Candida albicans and Candida krusei were studied for their sensitivity to the fungicidal effect of human lactoferrin. Significant inter- and intraspecies variations were observed and with most isolates the sensitivity of C. krusei to lactoferrin was greater than that of C. albicans. Fungicidal activity of lactoferrin was dose-dependent and observable only with the iron-free form of the molecule (apo-lactoferrin). Iron-saturated lactoferrin was ineffective against all isolates. Supernatant protein assays and scanning electron microscopy indicated cell surface alterations-leakage of proteins and formation of surface blebs-only in those Candida isolates that were sensitive to apo-lactoferrin. As lactoferrin is a common, non-immune, mucosal defense protein, its varying mode of action against C. albicans and C. krusei may be related to their different oral carriage rates. Archives of Oral Biology, 1993 Dec, 38 (12):1057-63.


20. Killing Of Candida Albicans By Lactoferricin B, A potent Antimicrobial Peptide Derived From The N-terminal Region Of Bovine Lactoferrin. Bellamy W; Wakabayashi H; Takase M;Kawase K;Shimamura S; Tomita M.

Abstract: Candida albicans was found to be highly susceptible to inhibition and inactivation by lactoferricin B, a peptide produced by enzymatic cleavage of bovine lactoferrin. Effective concentrations of the peptide varied within the range of 18 to 150 micrograms/ml depending on the strain and the culture medium used. Its effect was lethal, causing a rapid loss of colony-forming capability. 14C-labeled lactoferricin B bound to C. albicans and the rate of binding appeared to be consistent with the rate of killing induced by the peptide. The extent of binding was diminished in the presence of Mg2+ or Ca2+ ions which acted to reduce its anticandidal effectiveness. Binding occurred optimally at pH 6.0 and killing was maximal near the same pH. Such evidence suggests the lethal effect of lactoferricin B results from its direct interaction with the cell surface. Cells exposed to lactoferricin B exhibited profound ultrastructural damage which appeared to reflect its induction of an autolytic response. These findings suggest that active peptides of lactoferrin could potentially contribute to the host defense against C. albicans. Medical Microbiology and lmmunology, 1993 May, 182(2).97-105.


21. Inhibition With Lactoferrin Of In Vitro Infection With Human Herpes Virus. Hasegawa K:, Mosucbi W; Tanaka S; Dosako S.

Abstract: Human lactoferrin (hLF) as well as bovine lactoferrin (bLF) inhibited infection of tissue culture cells with human cytomegalovirus (HCMV) and human herpes simplex virus-1 (HSV-l). The addition of lactoferrin (LF) inhibited both in vitro infection and replication of HCMV and HSV-l in human embryo lung host cells. The maximum inhibition by more than six exponentials of TCID50 for HCMV and four exponentials for HSV-l was obtained at a concentration in a range from 0.5 to 1 mg of LF per ml of medium. The antiviral activity of LF was associated with its protein moiety, but not with its iron molecule or sialic acid. None of other transferrin gene family members bound to ferrous ions or sialic acid possessed significant antiviral activity. Additionally, we found that LF prevented virus adsorption and/or penetration into host cells, indicating an effect on the early events of virus infection. Preincubation of host cells with LF for 5 to 10 min. was sufficient to prevent HCMV infection, even when LF was removed after addition of virus. These results suggest that LF possesses a potent antiviral activity and may be useful in preventing HCMV and HSV-l infection in humans. Japanese Journal of Medical Science and Biology, 1994 Apr, 472):735.


22. Antiviral Effects Of Plasma And Milk Proteins: Lactoferrin Shows Potent Activity Against Both Human Immunodeficiency Virus And Human Cytomegalovirus Replication In Vitro. Martin C. Harmsen, Pieter J. Swart, Marie-Pierre de Bethune, Rudi Pauweis, Erik De Cleroq, Hanw Tbe, and Dirk K F. Meljer.

Native and chemically derivatized proteins purifies from serum and milk were assayed in vitro to access their inhibiting capacity on the cytopathic effect of human immunodeficiency virus (HIV)-1 and human cytomegalovirus (HCMV) on MT4 cells and fibroblasts, respectively. Only native and conformationally intact lactoferrin from bovine or human milk, colostrum, or serum could completely block HCMV infection (IC50 = 35 -100 ug/mL). Moreover, native lactoferrin also inhibited the HlV-1-induced cytopathic effect (IC50 = 40 40 ug/mL). When negatively charged groups were added to lactoferrin by succinylation, there was a 4-fold stronger antiviral effect on HIV-1, but the antiviral potency to HCMV infection was mostly decreased. Lactoferrin likely exerts its effects at the level of virus adsorption or penetration (or both), because after HCMV penetrated fibroblasts, the ongoing infection could not be further inhibited. The Journal of Infectious Diseases 1995;172.383

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