This data suggests that CXCR6 and CXCL16 may play a role in T cell recruitment to the lung.

Lactoferrin (Lf) is an iron-binding protein of external secretions and neutrophil secondary granules with antimicrobial and immunomodulatory activities. To further define these properties of Lf, we have investigated the response to Staphylococcus aureus infection in transgenic mice carrying a functional human Lf gene. The transgenic mice cleared bacteria significantly better than congenic littermates, associated with a trend to reduced incidence of arthritis, septicemia, and mortality. We identified two pathways by which S. aureus clearance was enhanced. First, human Lf directly inhibited the growth of S. aureus LS-1 in vitro. Second, S. aureus-infected transgenic mice exhibited enhanced Th1 immune polarization. Thus, spleen cells from infected transgenic mice produced higher levels of TNF-α and IFN-γ and less IL-5 and IL-10 upon stimulation ex vivo with the exotoxin toxic shock syndrome toxin-1 compared with congenic controls. To confirm that these effects of Lf transgene expression could occur in the absence of live bacterial infection, we also showed that Lf-transgenic DBA/1 mice exhibited enhanced severity of collagen-induced arthritis, an established model of Th1-induced articular inflammation. Higher levels of stainable iron in the spleens of transgenic mice correlated with human Lf distribution, but all other parameters of iron metabolism did not differ between transgenic mice and wild-type littermates. These results demonstrate that human Lf can mediate both antimicrobial and immunomodulatory activities with downstream effects on the outcome of immune pathology in infectious and inflammatory disease.

The chemokine receptor CXCR6 is highly expressed on lung-derived T cells compared to blood T cells, especially in inflammatory diseases characterised by T-cell migration to the lung. This suggests that CXCR6 is a candidate lung homing receptor. The sole ligand of CXCR6, CXCL16, has previously been shown to be expressed by alveolar macrophages. The authors hypothesized that also structural lung cells express CXCL16. CXCL16 expression was detected using real-time reverse transcriptase–polymerase chain reaction (RT-PCR), Western blotting, enzyme-linked immunosorbent assay (ELISA), and flow cytometry. Chemotaxis assays were used to test functionality of the secreted protein. Human bronchial epithelial cells secreted relatively high basal levels of CXCL16 (> 1000 pg/mL). Interferon (IFN)-γ, but not tumor necrosis factor (TNF)-α or interleukin (IL)-4, caused a modest but significant up-regulation in secretion. Airway smooth muscle and fibroblasts also expressed CXCL16, but at lower levels. Western blotting detected expression of the full-length (60-kDa) form of the chemokine in cell lysates, and the cleaved (35-kDa) form in culture supernatants. Concentrated supernatants from a bronchial epithelial cell line (BEAS-2B) were chemotactic for CXCR6 expressing T cells from blood. In conclusion, these results suggest that the bronchial epithelium is an important source of constitutively expressed CXCL16, which may be involved in T-cell recruitment to the lung in health and disease.

Objective. To determine whether lactoferrin can modify articular inflammation in murine models of autoimmune and septic arthritis. Methods. Collagen arthritis was induced in DBA/1 mice and Staphylococcus aureus septic arthritis in Swiss mice. Joints with established inflammation were injected periarticularly with 0.5 mg or 1 mg of human lactoferrin, and arthritis was monitored for 3 days. Results. DBA/1 mice injected with lactoferrin showed significantly suppressed local inflammation for up to 3 days, achieving up to 71% of the effect of corticosteroid. Periarticular injection of 125 I-lactoferrin confirmed that 25% of lactoferrin was retained in paws after 6 hours. Serum levels of interleukin-6, however, were not significantly reduced, suggesting a predominantly local antiinflammatory effect. Similarly, local, periarticular administration of lactoferrin into S aureus-infected Swiss mice significantly suppressed paw inflammation and did not enhance bacterial survival. Conclusion. Lactoferrin may have clinical utility in reducing articular inflammation, particularly in septic arthritis, in which antiinflammatory effects may be achieved without promoting bacterial survival.

Liposomes prepared from naturally occurring biodegradable and nontoxic lipids are good candidates for local delivery of therapeutic agents. Treatment of arthritis by intra-articular administration of anti-inflammatory drugs encapsulated in liposomes prolongs the residence time of the drug in the joint. We have previously shown that intra-articular injection of human lactoferrin (hLf), a glycoprotein that possesses anti-inflammatory and antimicrobial activities, into mice with collagen-induced arthritis reduces inflammation. We have now investigated the possibility of using liposome-entrapped hLf as a delivery system to prolong hLf retention at sites of local inflammation such as the rheumatoid joint. Entrapment of hLf in negatively charged liposomes enhanced its accumulation in cultured human synovial fibroblasts from rheumatoid arthritis (RA) patients, compared with positively charged formulations or free protein. However, in the presence of synovial fluid, positively charged liposomes with entrapped hLf were more stable than the negatively charged formulations. In vivo experiments in mice with collagen-induced arthritis showed that the positive liposomes were more efficient in prolonging the residence time of hLf in the inflamed joint as compared with other liposomes. Thus, the amount of hLf retained in the joint after 2 hr was 60% of the injected dose in the case of positive liposomes and only 16% for negative pH-sensitive liposomes. The results suggest that entrapment of hLf in positively charged liposomes may modify its pharmacodynamic profile and be of therapeutic benefit in the treatment of RA and other local inflammatory conditions.

Mast cell-derived prostaglandin D2 (PGD2) is the major prostanoid found within the airway of asthmatics immediately following allergen challenge. PGD2 has been shown to have chemokinetic effects on eosinophils and T helper type 2 (Th2) cells in vitro. This occurs through the interaction of PGD2 with the G-protein-coupled chemokine receptor homologous molecule expressed on Th2 lymphocytes (CRTH2). The expression of CRTH2 has been shown to be highly selective for Th2 cells. Using flow cytometry we have studied the expression of CRTH2 on T cells in blood and bronchoalveolar lavage fluid in asthmatics and normal subjects. CRTH2 expression was confined to a small percentage of blood T cells in asthmatics (1·8% ± 0·2) and normal (1·6% ± 0·2) subjects. CRTH2 was enriched significantly on interleukin (IL)-4+/IL-13+ T cells compared to interferon (IFN)-γ+ T cells (P < 0·001). There was a small population of CRTH2+ T cells in the bronchoalveolar lavage (BAL) of asthmatics (2·3% ± 0·6) and normal subjects (0·3% ± 0·1), and there was a significant difference between the two groups (P < 0·05). There were similar amounts of PGD2 in the BAL of asthma and normal subjects. Within paired blood–BAL samples from the same subject there was no increase in CRTH2+ T cells in the BAL compared to blood in asthmatics. Enrichment of CRTH2 on IL-4+ and IL-13+ T cells compared to IFN-γ+ T cells was also seen in BAL from asthmatics (P < 0·001). CRTH2 is expressed preferentially by IL-4+/IL-13+ T cells compared to IFN-γ+ T cells. However, given their small numbers they are unlikely to have a significant involvement in the pathogenesis of asthma. CRTH2 antagonism may not diminish T cell accumulation in the asthmatic lung.

BackgroundChemokines and their receptors could play key roles in the recruitment of T cells to the asthmatic lung. CCR8 is preferentially expressed on T-helper type 2 cells, and is thought to play a role in the pathogenesis of human asthma.ObjectiveDetermine the expression of CCR8 on T cells in blood, bronchoalveolar lavage (BAL) and bronchial mucosa from asthmatics and normal subjects.MethodsCCR8 expression in blood and BAL from asthma and normal subjects was studied using flow cytometry. CCR8 expression on IFN-γ+ and IL-4+/IL-13+ blood and BAL T cells was studied following stimulation with Phorbol–Myristate–Acetate and Calcium Ionophore. Paraffin-embedded bronchial biopsies were used to study CCR8 in bronchial epithelium.ResultsThe percentage of CD3+ cells expressing CCR8 in the blood was higher in asthmatics (4.7±0.4%) compared with normal subjects (3.0±0.4%; P<0.01). There was an approximately sixfold enrichment of CCR8 on IL-4+/IL-13+ cells compared with IFN-γ+ T cells (P<0.001) in both asthmatic and normal subjects in both blood and BAL. Significantly more BAL T cells expressed CCR8 in asthmatic (8.6±0.8%) compared with normal subjects (3.9±0.7%) (P<0.01). In paired blood-BAL samples from asthmatics, significantly more CCR8+CD3+ T cells were present in BAL (9.0±0.9%) than in blood (5.6±0.9%; P<0.05). There were more CCR8-positive cells in bronchial biopsies from asthmatic (93±11 cells/mm2) compared with normal subjects (30±16 cells/mm2) (P<0.05). The ligand CCL1 was increased in the BAL of asthmatics compared with normal subjects (35±6 vs. 12.9±7 pg/mL; P<0.05).ConclusionThere may be a role for CCR8 in the recruitment of T cells to the lung in asthmatics.Cite this as: K. Mutalithas, C. Guillen, C. Raport, R. Kolbeck, D. Soler, C. E. Brightling, I. D. Pavord and A. J. Wardlaw, Clinical & Experimental Allergy, 2010 (40) 1175–1185.

Objectives-To determine the ability of lactoferrin in rheumatoid arthritis (RA) synovial fluid to bind "free" iron, and to study the regulatory mechanisms therein that control iron homeostasis. Methods-"Free" iron was determined by the bleomycin assay and lactoferrin concentrations by enzyme linked immunosorbent assay. The activities of iron regulatory protein (IRP) and NF-B in synovial fluid cells were assayed by mobility shift assay. Results-30% of synovial fluids contained "free" iron and in these, lactoferrin concentrations were significantly lower than in those with no "free" iron (p<0.01).