Lactoferrin decreases pollen antigen-induced allergic airway inflammation in a murine model of asthma

Lactoferrin regulates an axis involving CD11b and CD49d integrins and the chemokines MIP-1α and MCP-1 in GM-CSF-treated human primary eosinophils

Eosinophils are multifunctional immune cells that contribute to innate and adaptive immune/repair responses. Lactoferrin (LF) is an iron-binding protein indicated to alter cell adhesion and immune function by receptor-mediated interactions or by participating in redox mechanisms. The eosinophil adhesion molecules, αMβ2 and α4β1, are differentially expressed following exposure to the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) and various redox agents. We hypothesized that LF can alter the function and production of proteins involved in adhesion/migration. Utilizing eosinophil peroxidase activity or fluorescent labeling adhesion assays, LF reduced GM-CSF-induced eosinophil adhesion in the presence of fibronectin or vascular adhesion molecule-1 compared with GM-CSF treatment alone. Flow cytometric analysis of eosinophil αM (CD11b) and α4 (CD49d) integrins revealed that cotreatments (24 h) with LF plus GM-CSF induced a significant increase in CD11b compared with control and GM-CSF treatments but a significant decrease in CD49d compared with control and GM-CSF treatments. These changes in CD11b and CD49d levels were significantly correlated with the increased production of chemokines (macrophage inflammatory Protein-1α, monocyte chemotactic protein-1) and an identified increase in S100A9 production. Thus, LF release at sites of inflammation may alter eosinophil recruitment/activation and possibly the progression of diseases such as cancer and asthma where significant eosinophil influx has been described.

The expression of ferritin, lactoferrin, transferrin receptor and solute carrier family 11A1 in the host response to BCG-vaccination and Mycobacterium tuberculosis challenge

Iron is an essential cofactor for both mycobacterial growth during infection and for a successful protective immune response by the host. The immune response partly depends on the regulation of iron by the host, including the tight control of expression of the iron-storage protein, ferritin. BCG vaccination can protect against disease following Mycobacterium tuberculosis infection, but the mechanisms of protection remain unclear. To further explore these mechanisms, splenocytes from BCG-vaccinated guinea pigs were stimulated ex vivo with purified protein derivative from M. tuberculosis and a significant down-regulation of ferritin light- and heavy-chain was measured by reverse-transcription quantitative-PCR (P≤0.05 and ≤0.01, respectively). The mechanisms of this down-regulation were shown to involve TNFα and nitric oxide. A more in depth analysis of the mRNA expression profiles, including genes involved in iron metabolism, was performed using a guinea pig specific immunological microarray following ex vivo infection with M. tuberculosis of splenocytes from BCG-vaccinated and naïve guinea pigs. M. tuberculosis infection induced a pro-inflammatory response in splenocytes from both groups, resulting in down-regulation of ferritin (P≤0.05). In addition, lactoferrin (P≤0.002), transferrin receptor (P≤0.05) and solute carrier family 11A1 (P≤0.05), were only significantly down-regulated after infection of the splenocytes from BCG-vaccinated animals. The results show that expression of iron-metabolism genes is tightly regulated as part of the host response to M. tuberculosis infection and that BCG-vaccination enhances the ability of the host to mount an iron-restriction response which may in turn help to combat invasion by mycobacteria.

Lactoferrin a multiple bioactive protein: an overview

BACKGROUND

Lactoferrin (Lf) is an 80kDa iron-binding glycoprotein of the transferrin family. It is abundant in milk and in most biological fluids and is a cell-secreted molecule that bridges innate and adaptive immune function in mammals. Its protective effects range from anticancer, anti-inflammatory and immune modulator activities to antimicrobial activities against a large number of microorganisms. This wide range of activities is made possible by mechanisms of action involving not only the capacity of Lf to bind iron but also interactions of Lf with molecular and cellular components of both hosts and pathogens.

SCOPE OF REVIEW

This review summarizes the activities of Lf, its regulation and potential applications.

MAJOR CONCLUSIONS

The extensive uses of Lf in the treatment of various infectious diseases in animals and humans has been the driving force in Lf research however, a lot of work is required to obtain a better understanding of its activity.

GENERAL SIGNIFICANCE

The large potential applications of Lf have led scientists to develop this nutraceutical protein for use in feed, food and pharmaceutical applications. This article is part of a Special Issue entitled Molecular Mechanisms of Iron Transport and Disorders.

Association of the -33C/G OSF-2 and the 140A/G LF gene polymorphisms with the risk of chronic rhinosinusitis with nasal polyps in a Polish population

Nasal polyps are strongly associated with a risk of chronic rhinosinusitis development as well as other obstruction including asthma and allergy. The following study tested the association of the 140A/G polymorphism of lactoferine (LF) encoding gene and the -33C/G polymorphism of osteoblast-specific factor-2 (OSF-2) encoding gene with a risk of chronic rhinosinusitis with nasal polyps in a Polish population. One hundred ninety five patients of chronic rhinosinusitis with nasal polyps as well as 200 sex, age and ethnicity matched control subjects without chronic sinusitis and nasal polyps were enrolled in this study. Among the group of patients 63 subjects were diagnosed with allergy and 65 subjects with asthma, respectively. DNA was isolated from peripheral blood lymphocytes of patients as well as controls and gene polymorphisms were analyzed by restriction fragments length polymorphism polymerase chain reaction (RFLP-PCR). We reported that the 140A/G LF (OR 4.78; 95% CI 3.07-7.24), the -33C/G OSF-2 OR 3.48; 95% CI 2.19-5.52) and the -33G/G OSF-2 (OR 16.45; 95% CI 6.71-40.30) genotypes were associated with an increased risk of chronic rhinosinusitis with nasal polyps among analyzed group of patients. Moreover, the group of patients without allergy or asthma indicated the association of the -33C/G (OR 3.72; 95% CI 2.24-6.19 and OR 15.11; 95% CI 5.91-38.6) and -33G/G (OR 3.73; 95% CI 2.24-6.19 and OR 14.07; 95% CI 5.47-36.16) genotypes of the OSF-2 as wells as 140A/G (OR 3.89; 95% CI 2.40-6.31 and OR 3.62; 95% CI 2.45-5.34) genotype of OSF-2 with an increased risk of chronic rhinosinusitis with nasal polyps. Finally, it was also found that the selected group of patients with allergy or asthma indicated a very strong association of the -33C/G (OR 2.40; 95% CI 1.23-4.69 and OR 2.40; 95% CI 1.23-4.69, respectively) and -33G/G (OR 16.01; 95% CI 5.77-44.41 and OR 17.90; 95% CI 6.53-49.05, respectively) genotypes of the OSF-2 as wells as 140A/G (OR 3.22; 95% CI 1.74-6.11 and OR 3.25; 95% CI 1.75-6.04, respectively) genotypes with an increased risk of chronic rhinosinusitis with nasal polyps. Thus, our results suggest that LF and OSF-2 gene polymorphisms may have deep impact on the risk of rhinosinusitis nasal polyps' formation which may also depend on asthma or allergy. Our results showed that the 140A/G polymorphism of LF gene and the -33C/G polymorphism of the OSF-2 gene may be associated with the risk of chronic rhinosinusitis with nasal polyps in a Polish population.

Lactoferrin, a key molecule in immune and inflammatory processes

Lactoferrin (Lf) belongs to the family of antimicrobial molecules that constitute the principal defense line of nonvertebrate organisms. In human immunity, their roles are considerably extended, and actually exceed mere direct antimicrobial properties. As a result, Lf is involved in both innate and adaptive immunities where its modulating effects not only help the host fight against microbes but also protect the host against harmful effects of inflammation. Such beneficial effects have been noticed in studies using dietary Lf, without the experimenters always explaining the exact modes of action of Lf. Effects on mucosal and systemic immunities are indeed often observed, which make the roles of Lf tricky to decipher. It is now known that the immunomodulatory properties of Lf are due to its ability to interact with numerous cellular and molecular targets. At the cellular level, Lf modulates the migration, maturation, and functions of immune cells. At the molecular level, in addition to iron binding, interactions of Lf with a plethora of compounds, either soluble or cell-surface molecules, account for its modulatory properties. This paper reviews our current understanding of the mechanisms that explain the regulatory properties of Lf in immune and inflammatory processes.

Iron administration reduces airway hyperreactivity and eosinophilia in a mouse model of allergic asthma

The prevalence of allergic diseases has increased dramatically during the last four decades and is paralleled by a striking increase in iron intake by infants in affluent societies. Several studies have suggested a link between increased iron intake and the marked increase in prevalence of allergic diseases. We hypothesized that the increased iron intake by infants offers an explanation for the increased prevalence of allergic disease in industrialized societies during the past four decades. A well-established mouse model of ovalbumin (OVA)-driven allergic asthma was used to test the effects of differences in iron intake and systemic iron levels on the manifestations of allergic asthma. Surprisingly, iron supplementation resulted in a significant decrease in airway eosinophilia, while systemic iron injections lead to a significant suppression of both allergen-induced airway eosinophilia and hyperreactivity compared to placebo. In contrast, mice fed on an iron-deprived diet did not show any difference in developing experimentally induced allergic asthma when compared to those fed on an iron-sufficient control diet. In contrast to our hypothesis, airway manifestations of allergic asthma are suppressed by both increased levels of iron intake and systemic iron administrations in the mouse model.

Effective treatment of experimental ragweed-induced asthma with STAT-6-IP, a topically delivered cell-penetrating peptide

BACKGROUND

Treatment of allergic airways disease including asthma remains primarily local immunosuppression with topical corticosteroid and symptomatic management with antihistamines and anti-leucotrienes. We have developed a novel topical therapy designed to specifically inhibit the events associated with Th2 cell activation.

OBJECTIVE

We assessed the efficacy of our cell-penetrating STAT-6 inhibitory peptide (STAT-6-IP), a novel treatment for allergic airways disease, in a model of chronic ragweed-induced asthma.

METHODS

Six- to eight-week-old mice were sensitized over 5 weeks with intranasal (IN) exposures to whole ragweed allergen without adjuvant. Mice were then IN challenged with Amba 1 with and without treatment IN with STAT-6-IP and allergic responses assessed. Two weeks later, some animals were rechallenged with Amba 1 with or without STAT-6-IP.

RESULTS

Animals exposed to IN ragweed developed significant airway hyperresponsiveness and airways inflammation upon challenge. Cell cultures showed increases in Th2 cytokines IL-4 and IL-13. Topical STAT-6-IP treatment reduced production of Th2 cytokines, demonstrated increased expression of IL-10 and reduced frequency of cultured IL-4 positive CD4+ T cells derived from treated mice, suggesting that STAT-6-IP treatment may be immunomodulatory. Airway responsiveness to methacholine challenge in the treatment group was similarly reduced to that of the non-allergic PBS-exposed animals. Importantly, STAT-6-IP-treated mice remained hyporesponsive following second ragweed challenge 2 weeks after treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

These data suggest that topical application of the STAT-6-IP is sufficient to inhibit allergic airways responses in animals chronically sensitized and challenged with ragweed. Data show that a single topical treatment course is sufficient to block signs of allergic responses to ragweed in the airways for at least 2 weeks. STAT-6-IP is a novel potential treatment for chronic allergic asthma.

Lactoferrin inhibits the growth of nasal polyp fibroblasts

The aim of this study was to evaluate the effects of lactoferrin (LF) on the growth of fibroblasts derived from nasal polyps. We showed that the proliferation of fibroblasts was inhibited in a dose-dependent manner by both native and recombinant LF. The greatest inhibition of proliferation was caused by human milk-derived, iron-saturated LF. The inhibition of fibroblast proliferation was not species specific because bovine LF also was active. The interaction between LFs and a putative cell receptor did not depend on the sugar composition of the glycan moiety of the LF molecule because lactoferrins of different origins were active and the addition of monosaccharides to the cultures did not block proliferation. However, the treatment of fibroblasts with sodium chlorate (an inhibitor of glycosaminoglycan sulfation) or the addition of heparin abolished the inhibitory effect of LF, suggesting that LF binds heparan sulfate-containing proteoglycans. The significance of LF in nasal excretions in controlling polyp formation is discussed.

Pro-oxidant iron in exhaled breath condensate: a potential excretory mechanism

AIMS

Pro-oxidant iron provides a potential measure of iron-catalysed oxidative stress in biological fluids. This study aimed, to investigate if the Bleomycin technique for measurement of pro-oxidant iron in biological fluids could be utilised for determinations in exhaled breath condensate (EBC). Secondly, to measure levels of pro-oxidant iron in EBC from asthmatics after exposure to polluting city environments.

METHODS

Retrospective analysis of samples of EBC and bronchoalveolar lavage fluid (BALF). Pro-oxidant iron levels were determined by the Bleomycin method. Transferrin levels were determined by radial diffusion immunoassay and lactoferrin by ELISA.

SUBJECTS

Patients undergoing surgery necessitating cardiopulmonary bypass, normal healthy controls, "healthy" smokers, and asthmatics (mild and moderate).

RESULTS

Pro-oxidant iron was significantly decreased (p<0.05) post cardiac surgery in both EBC and BALF. In smokers levels of pro-oxidant iron in EBC were significantly (p<0.05) increased verses healthy controls. In asthmatics with more severe disease, there were significant increases in EBC pro-oxidant iron content post exposure to city environments (p<0.001), with levels most elevated after exposure to the most polluted setting.

CONCLUSION

Similar patterns in the levels of pro-oxidant iron detectable in EBC and paired BALF from patients undergoing cardiopulmonary bypass (pre and post surgery) suggest a potential for EBC determinations. Significantly elevated levels in EBC from smokers relative to control subjects provide further support for this technique. In asthma disease severity and environmental exposure influenced levels of pro-oxidant iron measured in EBC indicating a potential for enhanced iron-catalysed oxidative stress.

A critical review of the roles of host lactoferrin in immunity

Lactoferrin (Lf) is an essential element of innate immunity, which refers to antigen-nonspecific defense mechanisms that a host uses immediately or within hours after exposure to an antigen. Following infection, Lf is released from neutrophils (PMNs) in blood and inflamed tissues and, such as other soluble pattern-recognition receptors of the innate immunity, Lf recognizes unique microbial molecules called pathogen-associated molecular patterns (PAMPs): LPS from the gram-negative cell wall and bacterial unmethylated CpG DNA. However, unlike classical PAMPs receptors involved in the activation of immune cells, Lf may act either as a competitor for these receptors or as a partner molecule, depending on the physiological status of the organism. These immunomodulatory properties are explained by the ability of Lf to interact with proteoglycans and receptors on the surface of mammalian cells: cells of the innate (NK cells, neutrophils, macrophages, basophils, neutrophils and mast cells) and adaptive [lymphocytes and antigen-presenting cells (APCs)] immune systems, and also epithelial and endothelial cells. Through these interactions, Lf is able to modulate the migration, maturation and functions of immune cells, and thus to influence both adaptive and innate immunities. The understanding of the roles of the host-expressed Lf in immunity comes from in vivo and in vitro studies with exogenous Lf which, although informative, rarely reflect the pathological, or non-pathological, conditions in the organism. In this review, the data from the literature will be critically analyzed in order to present a real picture of the regulatory roles of host Lf in immunity.

Inhibition of eosinophil migration by lactoferrin

Eosinophilic granulocytes are innate effector cells that are important in immune responses against helminth parasitic infections and contribute towards the pathology associated with allergic inflammatory conditions, including allergic rhinitis and asthma. Their recruitment to inflammatory sites occurs in response to chemotactic and activation signals, such as eotaxin and interleukin-5, and is a tightly controlled process. However, the mechanisms that counterbalance these positive chemoattractive processes, thereby preventing excessive eosinophil infiltration, have received little attention. Here, we show that, lactoferrin (LTF), a pleiotropic 80-kDa glycoprotein with iron-binding properties, acts as a powerful inhibitor of eosinophil migration. Irrespective of its source (milk or neutrophil derived), LTF inhibits eotaxin-stimulated eosinophil migration with no effects on eosinophil viability. Transferrin, a closely related cationic glycoprotein, failed to produce an analogous effect. Furthermore, the iron-saturation status of LTF did not influence the observed inhibitory effect on migration, proving that LTF exerts its effect on eosinophil chemotaxis independent of its iron-chelating activity. These results highlight LTF as one of the few molecules reported to negatively regulate eosinophil migration. Thus, through its ability to inhibit eosinophil migration, LTF has potential as an effective therapeutic in the control of eosinophil infiltration in atopic inflammatory conditions.

Lactoferrin decreases LPS-induced mitochondrial dysfunction in cultured cells and in animal endotoxemia model

Lactoferrin is a non-heme iron-binding glycoprotein, produced by mucosal epithelial cells and granulocytes in most mammalian species. It is involved in regulation of immune responses, possesses anti-oxidant, anti-carcinogenic, anti-inflammatory properties, and provides protection against various microbial infections. In addition, lactoferrin has been implicated in protection against the development of insult-induced systemic inflammatory response syndrome (SIRS) and its progression into septic conditions in vivo. Here we show a potential mechanism by which lactoferrin lessens oxidative insult at the cellular and tissue levels after lipopolysaccharide (LPS) exposure. Lactoferrin pretreatment of cells decreased LPS-mediated oxidative insults in a dose-dependent manner. Lipopolysaccharide-induced oxidative burst was found to be of mitochondrial origin, and release of reactive oxygen species (ROS) was localized to the respiratory complex III. Importantly, lactoferrin nearly abolished LPS-induced increases in mitochondrial ROS generation and the accumulation of oxidative damage in the DNA. In vivo, pretreatment of experimental animals with lactoferrin significantly (P<0.05) lowered LPS-induced mitochondrial dysfunction as shown by both decreased release of H(2)O(2) and DNA damage in the mitochondria. In contrast, deferoxamine, an iron chelating compound, provided only partial protection in LPS-treated animals. Together, these data suggest that lactoferrin protects against oxidative insult at the mitochondrial level, and indicate a potential utility of lactoferrin in prevention and treatment of SIRS.

A novel recombinant human lactoferrin augments the BCG vaccine and protects alveolar integrity upon infection with Mycobacterium tuberculosis in mice

Lactoferrin, an iron binding glycoprotein, possesses multiple immune modulatory activities, including the ability to promote antigen specific cell-mediated immunity. Previous studies showed that adding bovine lactoferrin to the BCG vaccine (an attenuated strain of Mycobacterium bovis Bacillus Calmette Guerin) resulted in increased host protective responses upon subsequent challenge with virulent Erdman Mycobacterium tuberculosis (MTB) in mice. The studies outlined here investigate utility of a novel recombinant human lactoferrin to enhance the BCG vaccine and protect against alveolar injury during experimental MTB infection in mice. Sialylated and non-sialylated forms of the recombinant human lactoferrin (rhLF), glycoengineered in yeast (Pichia pastoris) and expressing humanized N-glycosylation patterns, were examined for their ability to enhance efficacy of the BCG vaccine in a murine TB model system. Results indicated that the sialylated form of the recombinant human lactoferrin generated increased antigen specific recall responses to BCG antigens. Furthermore, augmented protection was demonstrated using the sialylated lactoferrin adjuvant with BCG, resulting in significant reduction in associated pathology following challenge with virulent organisms.

Lactoferrin and cancer disease prevention

Lactoferrin (LF) is an iron-binding glycoprotein that is composed of the transferrin family and is predominantly found in the products of the exocrine glands located in the gateways of the digestive, respiratory, and reproductive systems, suggesting a role in the non-specific defence against invading pathogens. Additionally, several physiological roles have been attributed to LF, namely regulation of iron homeostasis, host defence against infection and inflammation, regulation of cellular growth, and differentiation and protection against cancer development and metastasis. These findings have suggested LF's great potential therapeutic use in cancer disease prevention and/or treatment, namely as a chemopreventive agent. This review looks at the recent advances in understanding the mechanisms underlying the multifunctional roles of LF and future perspectives on its potential therapeutic applications.

Lactoferrin as a natural immune modulator

Lactoferrin, an iron-binding glycoprotein, is a cell-secreted mediator that bridges innate and adaptive immune function in mammals. It is a pleiotropic molecule that directly assists in the influence of presenting cells for the development of T-helper cell polarization. The aim of this review is to provide an overview of research regarding the role of lactoferrin in maintaining immune homeostasis, in particular as a mediator of immune responses to infectious assault, trauma and injury. These findings are critically relevant in the development of both prophylactic and therapeutic interventions in humans. Understanding these particular effects of lactoferrin will provide a logical framework for determining its role in health and disease.

The effect of air pollution on asthma and allergy

Air pollution exposure is associated with increased asthma and allergy morbidity and is a suspected contributor to the increasing prevalence of allergic conditions. Observational studies continue to strengthen the association between air pollution and allergic respiratory disease, whereas recent mechanistic studies have defined the prominent role of oxidative stress in the proallergic immunologic effects of particulate and gaseous pollutants. The identification of common genetic polymorphisms in key cytoprotective responses to oxidative stress has highlighted the importance of individual host susceptibility to pollutant-induced inflammation. Future therapy to reduce the adverse effects of air pollution on allergic respiratory disease will likely depend on targeting susceptible populations for treatment that reduces oxidative stress, potentially through enhancement of phase 2 enzymes or other antioxidant defenses.

Role of pollen NAD(P)H oxidase in allergic inflammation

PURPOSE OF REVIEW

Plant pollens are one of the most common outdoor allergens. Pollen grains and subpollen particles can reach lower airways and induce symptoms of seasonal asthma and allergic rhinitis. Plants possess NAD(P)H oxidase activity that generates reactive oxygen species for physiological functions such as root-hair and pollen-tube growth, defense against microbial infections and cell signaling. The presence of NAD(P)H oxidases in pollens and their role in induction of airway inflammation have not been described until recently.

RECENT FINDINGS

We discovered the presence of NAD(P)H oxidase in ragweed and other plant pollens. These oxidases induce reactive oxygen species in mucosal cells (signal 1) independent of adaptive immunity. This reactive oxygen species facilitates antigen (signal 2)-induced allergic inflammation. Inhibiting signal 1 by administration of antioxidants attenuated ragweed extract-induced allergic inflammation. Likewise, abrogating signal 2 by antigen challenge in mice lacking T cells failed to induce allergic inflammation.

SUMMARY

Reactive oxygen species generated by pollen NAD(P)H oxidase play a major role in pathogenesis of allergic airway inflammation and airway hypersensitivity. Based on our findings, we propose a 'two signal hypothesis of allergic inflammation' in which both signal 1 (reactive oxygen species) and signal 2 (antigen presentation) are required in order to induce full-blown allergic inflammation.

Oxidative stress and the eye

Oxidative and particularly photo-oxidative processes are critical factors many ocular conditions but are often poorly recognized by those investigating ocular disease. The author discusses oxidative stress in inflammatory processes of the conjunctiva, cornea, and uvea; in cataract formation in the lens; in retinal degeneration; and in optic nerve pathologic conditions, inflammatory in optic neuritis and degenerative in glaucoma.

Bovine lactoferrin potently inhibits liver mitochondrial 8-OHdG levels and retrieves hepatic OGG1 activities in Long-Evans Cinnamon rats

BACKGROUND/AIMS

To assess the effect of lactoferrin on oxidative liver damage and its mechanism, we used Long-Evans Cinnamon (LEC) rats that spontaneously develop fulminant-like hepatitis and lethal hepatic failure.

METHODS

Four-week-old female LEC rats were divided into the untreated and treated groups. The latter was fed bovine lactoferrin at 2% mixed with conventional diet.

RESULTS

The cumulative survival rates were 75.0% vs. 100% at 14 weeks, 37.5% vs. 91.7% at 15 weeks, and 12.5% vs. 91.7% at 16 weeks, respectively, for untreated and treated rats (P=0.0008). The 8-OHdG levels in liver mitochondrial DNA and malondialdehyde in plasma and liver tissues were significantly lower in treated than untreated rats (P<0.001, =0.017 and 0.034, respectively). Mitochondrial DNA mutations were more common in untreated rats. OGG1 mRNA and protein expression levels were significantly lower in untreated than treated rats (P=0.003 and 0.007, respectively). Hypermethylation of the second CpG island located upstream of OGG1 gene was observed in untreated rats.

CONCLUSIONS

Our findings indicated that lactoferrin inhibits oxidative liver damage in LEC rats. Lactoferrin could be potentially useful for the treatment of oxidative stress-induced liver diseases.

Inflammatory effect of environmental proteases on airway mucosa

Proteases--both endogenous proteases from the coagulation cascade, mast cells, and respiratory epithelial trypsin, and exogenous proteases from parasites, insects, mites, molds, pollens, and other aeroallergens--stimulate a tissue response that includes attraction and activation of eosinophils and neutrophils, degranulation of eosinophils and mast cells, increased response of afferent neurons, smooth muscle contraction, angiogenesis, fibrosis, and production of immunoglobulin E. This response to exogenous proteases can be considered a form of innate immunity directed against multicellular organisms. The response of the airways to environmental proteases very closely resembles the response to airborne allergens. Although clinical research in this area is just beginning, the response to environmental proteases appears to be important in the pathogenesis of rhinitis and asthma developing from damp, water-damaged buildings, and intrinsic asthma with its associated rhinosinusitis and polyps.

Lactoferrin modulation of IL-12 and IL-10 response from activated murine leukocytes

Lactoferrin possesses a wide range of immunomodulatory activities, including promotion of the delayed type hypersensitivity response (DTH) towards BCG (Bacillus Calmette Guerin) antigens. Addition of Lactoferrin as an adjuvant to the BCG vaccine was previously demonstrated to augment protection against subsequent mycobacterial challenge, with concomitant development of a strong T cell helper type 1 (TH1) immunity. Because generation of TH1 immunity is in large part dependent on the balance of monocytic pro- and anti-inflammatory cytokines, the effect of Lactoferrin on leukocytes was investigated. Lactoferrin enhanced proinflammatory responses in a dose-dependant manner from splenocyte and adherent (F4/80+) splenocyte populations, bone marrow derived monocytes (BMM), and J774A.1 cultured cells. In all scenarios tested, Lactoferrin induced a strong increase in the ratio of IL-12:IL-10 production from LPS stimulated cells. Examination of Lactoferrin effects on BCG infected J774A.1 cells and on BMM revealed similar immunomodulatory effects, with particularly strong increase in IL-12 production. Furthermore, immunization of mice with BCG admixed with Lactoferrin led to increased generation of CD4+ cells expressing IFN-gamma upon restimulation with BCG antigens. These results provide molecular evidence to support the role of Lactoferrin as an adjuvant candidate to augment development of DTH response to vaccine antigens.