Search PubMed⌕ Search

Biomedical subjects

I Kimber

Publications and source records attributed to I Kimber.

At least 19 recordsLinked to original sources
PubMed2006

Proteomic analysis of suction blister fluid isolated from human skin.

The regulation of cutaneous immune responses in health and disease is mediated locally by proteins such as cytokines and chemokines. We used a novel approach involving proteomic profiling of fluid drawn from suction blisters to compare and contrast protein expression in normal skin with that in nonlesional skin from a patient with plaque psoriasis. We also examined the impact of exogenous interleukin-1beta, a proinflammatory cytokine, on protein expression in these tissues. Described here are the results of proteomic profiling of 670 proteins from blister fluid, and the identification by differential expression of nine proteins between one volunteer with psoriasis and one normal volunteer. Although the apparent disease association of these nine proteins will require validation using additional volunteers, the identification of candidate protein biomarkers through proteomic analyses of blister fluid represents a promising approach for monitoring the disease activity and efficacy of therapeutic intervention in human skin diseases.

Biomarkers↗
PubMed2006

The local lymph node assay in practice: a current regulatory perspective.

Following the formal acceptance of the local lymph node assay (LLNA) as an Organization for Economic Cooperation and Development (OECD) guideline in April 2002, the UK Health and Safety Executive (HSE) informed notifiers that this was now the method of choice for the assessment of skin sensitization potential under the EU notification scheme for new industrial chemicals (NONS). This paper summarizes the experience of the HSE for the 2-year period immediately following the issuing of this statement, during which 48 LLNA study reports were assessed for notification purposes. The issues discussed here include adherence to the OECD guideline, interpretation of results, and classification outcomes. Generally, notifying laboratories followed the OECD guideline successfully, with regard to the sex/ strain/numbers of mice used, the precise process used for measurement of cell proliferation, and the use of recommended vehicles and positive controls. Initially, use of the individual animal approach (measuring the cell proliferation in each animal rather than for a pooled dose group) highlighted problems caused by technical inexperience, but these were overcome by practice. Toxicity or irritation were found to be minor factors in dose selection; more important was the choice of vehicle to correctly maximize the test substance concentration, while maintaining appropriate application properties. Contrary to concerns that the LLNA would prove to be less sensitive or more sensitive than the traditionally used Guinea Pig Maximization Test (GPMT), the proportion of new substances classified as skin sensitizers was within the range observed in previous years. Although the sample size is relatively small, the experience of the HSE indicates that the LLNA is satisfactory for routine regulatory use.

Animals↗
PubMed2005

Cytokines and Langerhans cell mobilisation in mouse and man.

A critical event during the development of cutaneous immune responses, including those provoked by contact allergens, is the mobilisation of epidermal Langerhans cells (LC). These cells act as sentinels of the immune system in the skin, responding to a variety of local insults with migration and delivery of potentially foreign signals to draining lymph nodes. Experimental studies have revealed that the regulation of mobilisation and migration of LC display striking similarities in man and mouse. In both species it has been found that the successful induction of migration requires that LC receive (at least) 2 independent cytokine signals; provided by tumour necrosis factor-alpha (TNF-alpha) and interleukin 1beta. In addition, a similar heterogeneity in man and mouse is apparent with regard to the fraction of LC responding rapidly to mobilisation signals, with the same proportion of cells (20%-30%) being stimulated to migrate in each case. Other similarities exist between mice and humans with respect to LC function, including an age-related decrement in both LC frequency and responsiveness to TNF-alpha. Collectively these studies demonstrate that the mouse provides a valuable experimental surrogate for the human skin immune system, particularly with respect to LC biology, and suggest that it is possible to perform extrapolations between species with some confidence.

Animals↗
PubMed2005

Evaluation of an in vitro method for the measurement of specific IgE antibody responses: the rat basophilic leukemia (RBL) cell assay.

The evaluation of allergenic potential is a key parameter in the safety assessment of novel proteins, including those expressed in genetically modified crops and foodstuffs. The majority of allergic reactions to food proteins are immediate type hypersensitivity reactions in which the principal biological effector is IgE antibody; the accurate measurement of specific IgE antibody is therefore a critical factor in experimental systems designed to characterize protein allergenic potential. Due to the presence of much higher concentrations of other immunoglobulin isotypes, the assessment of specific serum IgE antibody poses substantial technical challenges. We have examined the utility of the rat basophilic leukemia (RBL) cell line for the measurement of murine IgE responses. RBL cells were sensitized with mouse monoclonal anti-dinitrophenyl (DNP) IgE antibody and challenged with DNP-albumin conjugates with various hapten substitution ratios (SR). Polyclonal anti-OVA IgE antisera were also assessed for activity in the RBL assay. Results were compared with titers measured in homologous passive cutaneous anaphylaxis (PCA) assay. Marked degranulation of RBL cells was induced by conjugates with SRs of between 16 and 32, whereas conjugates with lower SRs (of 10 or 3) failed to elicit significant serotonin release. All conjugates were able to induce mast cell degranulation in vivo in a PCA assay. Anti-OVA antisera with PCA titers of 1/32 to 1/64 failed to stimulate RBL cell degranulation, whereas high titer antibody (1/2048 to 1/4096 by PCA) induced a positive RBL cell response. Successful stimulation of RBL cell degranulation requires not only appropriate epitope densities but also high affinity antibody. These data indicate that this assay is inappropriate for the routine analysis of specific polyclonal IgE antibody responses such as those that are induced by exposure to complex protein allergens.

Allergens↗
PubMed2005

Allergen-induced cytokine phenotypes in mice: role of CD4 and CD8 T cell populations.

BACKGROUND: CD4+ T cells expressing type 2 cytokines have been implicated in the pathogenesis of asthma to high-molecular-weight allergens. Topical exposure of BALB/c strain mice to low-molecular-weight chemical contact and respiratory allergens stimulates type 1 and type 2 cytokine secretion phenotypes, respectively. OBJECTIVE: To examine the relative frequencies of cytokine-positive CD4+ and CD8+ T cells and their contributions to these cytokine secretion profiles. Methods Draining auricular lymph nodes were isolated 13 days after initiation of topical exposure of female BALB/c strain mice to chemical allergen, or to vehicle alone. The frequency of intracellular cytokine (IL-4 and IFN-gamma)-positive CD4+ and CD8+ lymphocytes was enumerated by flow cytometry. The relative contribution of CD4+ and CD8+ cells to cytokine secretion profiles was assessed by negative selection. RESULTS: Exposure to allergen resulted in an increased frequency of both IFN-gamma+ CD4+ and CD8+ lymphocytes, although there were no marked differences between trimellitic anhydride (TMA)- and 2,4-dinitrochlorobenzene (DNCB)-activated lymph node cells. Treatment with TMA induced approximately five times as many IL-4+ CD4+ cells as did exposure to DNCB. This pattern of cytokine staining was also observed for a further pair of contact and respiratory allergens; respectively, formalin and fluorescein isothiocyanate. CONCLUSION: These data demonstrate that the divergent immune responses induced in mice by different classes of chemical allergen are independent of changes in the frequency of IFN-gamma+ cells, but are associated with differential frequencies of IL-4-expressing CD4+ T cells.

Allergens↗
PubMed2005

Epicutaneous exposure to peanut protein prevents oral tolerance and enhances allergic sensitization.

BACKGROUND: Food allergies are an important cause of life-threatening hypersensitivity reactions. Oral tolerance can be considered the default immune response to dietary antigens, with immune deviation resulting in allergic sensitization. However, primary sensitization to food allergens may not solely be through the gastrointestinal mucosa, as strong T-helper type 2 (Th2)-biased immunity can result from exposure to protein allergens on barrier-disrupted skin. OBJECTIVE: The purpose of this study was to examine whether exposure to allergens through the skin may interfere with the normal development of oral tolerance and promote allergic sensitization to food proteins. METHODS: Female BALB/c mice were exposed epicutaneously to peanut protein and induction of systemic oral tolerance through high dose feeds of peanut protein was subsequently assessed. Other mice were rendered tolerant prior to epicutaneous peanut exposure. Sensitivity to peanut was determined by assessing delayed-type hypersensitivity, proliferative, cytokine and antibody responses. RESULTS: Epicutaneous exposure to peanut protein induced potent Th2-type immunity with high levels of IL-4 and serum IgE. Primary skin exposure prevented the subsequent induction of oral tolerance to peanut in an antigen-specific manner. Upon oral challenge, mice became further sensitized and developed strong peanut-specific IL-4 and IgE responses. Furthermore, animals with existing tolerance to peanut were partly sensitized following epicutaneous exposure. CONCLUSION: Epicutaneous exposure to peanut protein can prevent induction of oral tolerance, and may even modify existing tolerance to peanut. Epidermal exposure to protein allergens selectively drives Th2-type responses, and as such may promote sensitization to food proteins upon gastrointestinal exposure.

Administration, Cutaneous↗
PubMed2005

Altered protein tyrosine phosphorylation in asthmatic bronchial epithelium.

A disease-related, corticosteroid-insensitive increase in the expression of epidermal growth factor (EGF) receptor (EGFR) tyrosine kinase in asthmatic bronchial epithelium has been shown previously by the current authors. To determine whether this is associated with enhanced intracellular signalling, the aim of this study was to evaluate epithelial tyrosine phosphorylation. Bronchial biopsies were analysed for the presence of phosphotyrosine by immunohistochemistry. Bronchial epithelial cells were exposed to EGF, hydrogen peroxide or tumour necrosis factor-alpha in vitro for measurement of tyrosine phosphorylated signalling intermediates and interleukin (IL)-8 release. Phosphotyrosine was increased significantly in the epithelium of severe asthmatics when compared with controls or mild asthmatics; however, in mild asthma, phosphotyrosine levels were significantly decreased when compared with controls. There was no significant difference between phosphotyrosine levels before or after 8 weeks of treatment with budesonide. Stimulation of bronchial epithelial cells resulted in tyrosine phosphorylation of several proteins, including EGFR, Shc and p42/p44 mitogen-activated protein kinase. In the presence of salbutamol, a transient partial suppression of EGFR phosphorylation occurred, whereas dexamethasone was without effect. Neither salbutamol nor dexamethasone inhibited EGF-stimulated IL-8 release. These data indicate that regulation of protein tyrosine kinase activity is abnormal in severe asthma. The epidermal growth factor receptor and/or other tyrosine kinase pathways may contribute to persistent, corticosteroid-unresponsive inflammation in severe asthma.

Administration, Inhalation↗
PubMed2005

Anti-proliferative effect of estrogen in breast cancer cells that re-express ERalpha is mediated by aberrant regulation of cell cycle genes.

Estrogen receptor (ER)-negative breast carcinomas do not respond to hormone therapy, making their effective treatment very difficult. The re-expression of ERalpha in ER-negative MDA-MB-231 breast cancer cells has been used as a model system, in which hormone-dependent responses can be restored. Paradoxically, in contrast to the mitogenic activity of 17beta-estradiol (E2) in ER-positive breast cancer cells, E2 suppresses proliferation in ER-negative breast cancer cells in which ERalpha has been re-expressed. We have used global gene expression profiling to investigate the mechanism by which E2 suppresses proliferation in MDA-MB-231 cells that express ERalpha through adenoviral infection. We show that a number of genes known to promote cell proliferation and survival are repressed by E2 in these cells. These include genes encoding the anti-apoptosis factor SURVIVIN, positive cell cycle regulators (CDC2, CYCLIN B1, CYCLIN B2, CYCLIN G1, CHK1, BUB3, STK6, SKB1, CSE1 L) and chromosome replication proteins (MCM2, MCM3, FEN1, RRM2, TOP2A, RFC1). In parallel, E2-induced the expression of the negative cell cycle regulators KIP2 and QUIESCIN Q6, and the tumour-suppressor genes E-CADHERIN and NBL1. Strikingly, the expression of several of these genes is regulated in the opposite direction by E2 compared with their regulation in ER-positive MCF-7 cells. Together, these data suggest a mechanism for the E2-dependent suppression of proliferation in ER-negative breast cancer cells into which ERalpha has been reintroduced.

Adenoviridae↗
PubMed2004

Assessment of the safety of foods derived from genetically modified (GM) crops.

This paper provides guidance on how to assess the safety of foods derived from genetically modified crops (GM crops); it summarises conclusions and recommendations of Working Group 1 of the ENTRANSFOOD project. The paper provides an approach for adapting the test strategy to the characteristics of the modified crop and the introduced trait, and assessing potential unintended effects from the genetic modification. The proposed approach to safety assessment starts with the comparison of the new GM crop with a traditional counterpart that is generally accepted as safe based on a history of human food use (the concept of substantial equivalence). This case-focused approach ensures that foods derived from GM crops that have passed this extensive test-regime are as safe and nutritious as currently consumed plant-derived foods. The approach is suitable for current and future GM crops with more complex modifications. First, the paper reviews test methods developed for the risk assessment of chemicals, including food additives and pesticides, discussing which of these methods are suitable for the assessment of recombinant proteins and whole foods. Second, the paper presents a systematic approach to combine test methods for the safety assessment of foods derived from a specific GM crop. Third, the paper provides an overview on developments in this area that may prove of use in the safety assessment of GM crops, and recommendations for research priorities. It is concluded that the combination of existing test methods provides a sound test-regime to assess the safety of GM crops. Advances in our understanding of molecular biology, biochemistry, and nutrition may in future allow further improvement of test methods that will over time render the safety assessment of foods even more effective and informative.

Animals↗
PubMed2004

Dendritic cells and skin sensitisation hazard assessment.

Allergic contact dermatitis is an important occupational and environmental health disease. There is a need, therefore, to identify skin sensitisation hazard, and to assess accurately likely risks to human health. During the past 15 years very significant advances have been made in our understanding of the cellular and molecular mechanisms that serve to initiate and regulate cutaneous immune responses, including the acquisition of skin sensitisation. This has facilitated parallel advances in the identification and characterisation of skin sensitising chemicals and the development of more robust approaches to risk assessment. It is relevant to consider whether advances in immunobiology provide opportunities also for the design of alternative approaches to the toxicological evaluation of skin sensitisation, including the development of in vitro methods. Here we review the potential use of strategies based on analysis of responses induced in Langerhans cells and dendritic cells; professional antigen processing and presenting cells that are known to play pivotal roles during the induction phase of adaptive immune responses.

Animals↗
PubMed2004

Differential regulation of mast cell cytokines by both dexamethasone and the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580.

Activated mast cells generate multiple cytokines but it is not known if these can be differentially regulated by pharmacological agents. We report here that the glucocorticoid dexamethasone (DEX) preferentially inhibited Ag-induced expression of IL-4 and IL-6 mRNA relative to TNF-alpha mRNA in RBL-2H3 cells. Likewise, the drug more readily inhibited release of IL-4 than TNF-alpha protein. SB203580, an inhibitor of p38 mitogen-activated protein kinase (MAPK), enhanced Ag-induced TNF-alpha mRNA expression without affecting IL-4 or IL-6 mRNA. At the protein level, SB203580 exerted little effect on TNF-alpha release but inhibited IL-4 release; notably, the ratio of TNF-alpha : IL-4 increased markedly with the concentration of SB203580, confirming the differential regulation of these cytokines. PD98059, an inhibitor of MAPK kinase (MEK), a component of the p44/42 MAPK pathway, partially inhibited Ag-induced expression of mRNA for all three cytokines while cyclosporin A inhibited Ag-induced IL-4 and IL-6 mRNA more readily than TNF-alpha mRNA. Ag activation of the cells led to phosphorylation of p38 and p44/42 MAPK but this was not influenced by DEX. In conclusion, mast cell cytokines can be differentially regulated pre- and post-translationally by DEX and SB203580 but there does not appear to be a direct mechanistic link between the actions of these two drugs.

Cells, Cultured↗
PubMed2003

Inhalation exposure to methylene chloride does not induce systemic immunotoxicity in rats.

Methylene chloride (dichloromethane) is used in a variety of industrial applications. To date, there has been no formal assessment of immunotoxicity attributed to methylene chloride. Studies were undertaken to examine whether methylene chloride has any potential to influence the integrity of immune function. For this purpose, Sprague-Dawley rats of both genders were exposed by inhalation to a single high dose (5000 ppm) of methylene chloride for 6 h/d, 5 d/wk for 28 d. This was considered the relevant route of administration, as not only is inhalation a primary route for human exposure to methylene chloride, but, also, the chemical is absorbed rapidly via the lungs. Under these conditions of exposure, methylene chloride failed to influence absolute or relative thymus weights in either gender and produced a significant reduction in relative, but not absolute, spleen weight in female rats only. Immunocompetence was measured as a function of the ability of treated animals to mount immunoglobulin M (IgM) antibody responses to sheep red blood cells (SRBC) as determined by enzyme-linked immunosorbent assay (ELISA). Exposure to methylene chloride did not affect antibody production. Evidence indicates that under these conditions of exposure, methylene chloride did not compromise immune function.

Administration, Inhalation↗
PubMed2003

Induction of IgE antibody responses by protein allergens: inter-laboratory comparisons.

There is a growing interest in the development of methods for the evaluation of the allergenic potential of novel proteins. One approach is the measurement of specific IgE antibody production stimulated by systemic (intraperitoneal; i.p.) exposure of BALB/c strain mice. In the current investigations, inter-laboratory comparisons have been performed of IgE antibody production induced in mice by food proteins of differing sensitizing potential. Female BALB/c strain mice (n=5) were exposed to 0.1% peanut agglutinin, an allergenic constituent of peanuts, to 2% ovalbumin (OVA), a major allergenic constituent of hens' egg, or to a protein considered to lack significant allergenicity, potato agglutinin (5%). Specific IgE antibody was measured by homologous passive cutaneous anaphylaxis assay and IgG and IgG1 antibody production was analysed by enzyme-linked immunosorbent assay (ELISA). Two independent experiments were conducted in each laboratory, but with all serological analyses conducted in one of the laboratories. Each of the proteins induced vigorous IgG and IgG1 antibody responses, with no statistically significant differences in titres recorded between laboratories. Furthermore, OVA and potato agglutinin induced responses of equivalent immunogenicity with respect to both IgG and IgG1 antibody titres. Administration of peanut agglutinin and OVA each stimulated marked IgE antibody responses in every experiment. In the two laboratories, titres ranged from 1:32 and 1:64 for peanut agglutinin, and from 1:8 and 1:32 for OVA. In contrast, exposure to potato agglutinin failed to induce vigorous IgE production, with no detectable IgE (negative with neat serum), or titres of 1 (positive with neat serum only) recorded. These data demonstrate that the induction of IgE antibody by food proteins of differing allergenic potential is a relatively robust phenomenon and transferable between laboratories. Furthermore, these results provide additional evidence that the measurement of antibody (IgE) responses in BALB/c mice may allow discrimination between allergens and those materials that apparently lack allergenicity.

Allergens↗
PubMed2003

Classification of contact allergens according to potency: proposals.

It is clear that contact allergens vary substantially with regard to the relative potency with which they are able to induce skin sensitisation. Considerations of potency will in the future become a significant factor in the classification of skin sensitising chemicals. It is therefore appropriate to establish what is known of potency and thresholds in the induction of skin sensitisation and the elicitation of allergic contact dermatitis, and to identify approaches that might be available for assessment of relative potency for the purposes of categorising chemical allergens. This paper was prepared by an ECETOC (European Centre for Ecotoxicology and Toxicology) Task Force that had the objective of recommending approaches for the measurement of potency and definition of thresholds for both the induction and elicitation of contact sensitisation. The deliberations recorded here build upon recommendations made previously by an ECETOC Task Force that considered the conduct of standard skin sensitisation test methods for the purposes of hazard identification and risk assessment (ECETOC, Monograph No. 29, Brussels, 2000). The emphasis in this present paper is also on standard and accepted methods for the assessment of skin sensitisation, and for which OECD guidelines are available: the local lymph node assay (LLNA), the guinea pig maximisation test and the occluded patch test of Buehler. For various reasons, discussed in detail herein, attention focused primarily upon consideration of categorisation of chemical allergens and the identification of thresholds with respect to the induction of skin sensitisation, rather than the elicitation of allergic contact dermatitis. It is concluded that although the LLNA is the method of choice for the determination of skin sensitisation potency for the purposes of categorisation, if data are already available from appropriate guinea pig tests then their judicious interpretation may provide information of value in determinations of potency and categorisation. Included here are detailed and specific recommendations for how best the results of the three test methods considered can be used for the categorisation of chemical allergens as a function of skin sensitisation potency.

Allergens↗
PubMed2003

The role of the epidermal growth factor receptor in sustaining neutrophil inflammation in severe asthma.

BACKGROUND: The extent of epithelial injury in asthma is reflected by expression of the epidermal growth factor receptor (EGFR), which is increased in proportion to disease severity and is corticosteroid refractory. Although the EGFR is involved in epithelial growth and differentiation, it is unknown whether it also contributes to the inflammatory response in asthma. OBJECTIVES: Because severe asthma is characterized by neutrophilic inflammation, we investigated the relationship between EGFR activation and production of IL-8 and macrophage inhibitory protein-1 alpha (MIP-1alpha) using in vitro culture models and examined the association between epithelial expression of IL-8 and EGFR in bronchial biopsies from asthmatic subjects. METHODS: H292 or primary bronchial epithelial cells were exposed to EGF or H2O2 to achieve ligand-dependent and ligand-independent EGFR activation; IL-8 mRNA was measured by real-time PCR and IL-8 and MIP-1alpha protein measured by enzyme-linked immunosorbent assay (ELISA). Epithelial IL-8 and EGFR expression in bronchial biopsies from asthmatic subjects was examined by immunohistochemistry and quantified by image analysis. RESULTS: Using H292 cells, EGF and H2O2 increased IL-8 gene expression and release and this was completely suppressed by the EGFR-selective tyrosine kinase inhibitor, AG1478, but only partially by dexamethasone. MIP-1alpha release was not stimulated by EGF, whereas H2O2 caused a 1.8-fold increase and this was insensitive to AG1478. EGF also significantly stimulated IL-8 release from asthmatic or normal primary epithelial cell cultures established from bronchial brushings. In bronchial biopsies, epithelial IL-8, MIP-1alpha, EGFR and submucosal neutrophils were all significantly increased in severe compared to mild disease and there was a strong correlation between EGFR and IL-8 expression (r = 0.70, P < 0.001). CONCLUSIONS: These results suggest that in severe asthma, epithelial damage has the potential to contribute to neutrophilic inflammation through enhanced production of IL-8 via EGFR- dependent mechanisms.

Adult↗
PubMed2003

Evaluation of protein allergenic potential in mice: dose-response analyses.

BACKGROUND: With the increasing interest in novel foods derived from transgenic crop plants, there is a growing need for the development of approaches for the characterization of the allergenic potential of proteins. Whereas immunogenicity is a common property of foreign proteins, including food proteins, relatively few are significant dietary allergens with the inherent capacity to provoke IgE antibody production and immediate-type hypersensitivity responses. OBJECTIVE: In order to evaluate an approach for the measurement of the allergenic potential of proteins, detailed dose-response analyses of humoral immune responses induced following systemic exposure of BALB/c strain mice to proteins known to differ in terms of sensitizing activity have been conducted. RESULTS: Mice were exposed to a range of concentrations of ovalbumin, a major allergenic constituent of hen's egg, a purified peanut allergen, Arachis hypogea agglutinin, or to the milk allergen bovine serum albumin, and to materials considered to lack significant allergenicity: a crude potato protein extract and a purified potato protein, potato agglutinin. The specific IgE antibody was measured by homologous passive cutaneous anaphylaxis assay, and the specific IgG antibody was measured by enzyme-linked immunosorbent assay. Each of the five proteins was immunogenic in mice, inducing IgG antibody responses at all doses tested, although there was some variation with respect to the vigour of IgG responses. Marked differences in the capacity of these proteins to induce IgE responses were observed, however, with relatively high-titre IgE antibody provoked by all three allergens over the dose ranges examined, whereas the potato proteins stimulated low-titre IgE antibody at the highest dose (10%) only. Importantly, differences in IgE antibody production have been observed against a background of equivalent immunogenicity (IgG antibody responses). CONCLUSION: The data presented here suggest that the measurement of antibody (IgE) responses in BALB/c mice appears to identify allergens accurately and to distinguish them from those materials that apparently lack allergenicity.

Allergens↗
PubMed2003

IL-1beta-induced Langerhans' cell migration and TNF-alpha production in human skin: regulation by lactoferrin.

In mice, the roles of cytokines in the initiation of epidermal Langerhans' cell (LC) migration are well documented; however, the mechanism of this response in humans is less well defined. The purpose of the present investigation was to examine the contribution of interleukin (IL)-1beta to human epidermal LC migration and to define further the mechanisms of this response. We demonstrate here that homologous recombinant IL-1beta administered intradermally to healthy human volunteers provides a stimulus for LC migration, with significant (P < 0.01) reductions in LC densities being observed at both 2 h and 4 h following treatment. At the later time-point of 4 h, injection of IL-1beta was also accompanied by activation of those LC remaining in the epidermis. Analysis of fluid aspirated from suction blisters formed at injection sites revealed significant (P < 0.01) tumour necrosis factor (TNF)-alpha production (2.99 +/- 1.18 pg TNF-alpha/mg protein; mean +/- s.d. of n = 10) in response to IL-1beta treatment compared with saline control injections (0.90 +/- 1.05 pg TNF-alpha/mg protein). Prior topical application of human recombinant lactoferrin (LF), an iron-binding protein found in exocrine secretions and skin, inhibited IL-1beta-mediated LC migration and also compromised the production of TNF-alpha protein as measured in suction blister fluids derived from each of the treatment sites. Taken together, these data demonstrate that IL-1beta is associated with both the stimulation of human epidermal LC migration and local TNF-alpha production. Topical treatment with LF compromises both these responses. These data suggest that topical LF may potentially represent a novel therapeutic in the treatment of skin inflammation where TNF-alpha is an important mediator.

Adult↗