BACKGROUND: 5-Oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE) is an arachidonic acid metabolite with potent in vitro chemoattractant effects on eosinophils and neutrophils. It has also been shown to induce pulmonary eosinophilia in Brown Norway rats, but it is not known whether it is active in human beings in vivo. OBJECTIVE: To determine whether 5-oxo-ETE can induce cellular infiltration in patients with atopic asthma and nonatopic control subjects after intradermal administration. METHODS: 5-Oxo-ETE was administered intradermally to 11 patients with atopic asthma and 10 nonatopic control subjects. Skin biopsy specimens were taken 6 or 24 hours later and examined by immunocytochemistry for cells expressing specific markers for eosinophils (major basic protein), neutrophils (elastase), macrophages (CD68), lymphocytes (CD3), and mast cells (tryptase). RESULTS: 5-Oxo-ETE (1.5 and 5 microg) elicited the infiltration of both eosinophils and neutrophils into the skin in both control and atopic asthmatic subjects. Increased numbers of eosinophils were observed at 6 and 24 hours after injection, whereas significantly elevated neutrophil numbers were present only after 24 hours. Eosinophils were >3 times higher in patients with atopic asthma compared with control subjects after injection of the highest dose of 5-oxo-ETE. Macrophage numbers were also elevated, but only at the highest dose of 5-oxo-ETE. No effects were observed on the numbers of either lymphocytes or mast cells. CONCLUSIONS: 5-Oxo-ETE elicits the infiltration of eosinophils and neutrophils into the skin of human beings in vivo after intradermal administration. Asthmatic subjects are more responsive to this substance than nonallergic control subjects. These results suggest that 5-oxo-ETE may be an important mediator of inflammation.
Proteoglycans (PG) have important effects on the mechanical properties of tissues, and the phenotype of various structural cells. Little is known about changes in PG deposition in the airways in animal models of asthma. We studied changes in PG in the airway wall of Brown Norway rats sensitized to ovalbumin (OA) and exposed to repeated OA challenge. Control (Sal) animals were sensitized and challenged with saline. After the 3rd challenge, animals were sacrificed and lungs fixed in formalin. Tissue sections were incubated with antibodies to the small, leucine-rich PG, decorin and biglycan, and collagen type I. Airways were classified according to basement membrane perimeter (Pbm) length (/=3mm). Decorin, biglycan and collagen type I, were increased in the airways of OA vs Sal rats. Remodeling was most prominent in central airways. The distribution of PG differed with respect to the subepithelial vs airway smooth muscle (ASM) vs adventitial layer. Whereas biglycan was readily detected within the ASM, decorin and collagen were detected outside the ASM, and especially in the adventitial layer. Differences in the distribution of these molecules within the layers of the airway wall may reflect their specific functional roles.
BACKGROUND: The function of CD8+ T-cell subsets in mediating late allergic responses is incompletely understood. OBJECTIVE: We sought to test the hypothesis that CD8+ alphabeta T cells are proinflammatory in the airways in vivo by using a well-characterized animal model and the technique of adoptive transfer. METHODS: Brown Norway rats were administered CD8 + alphabeta T cells (10 6 ) intraperitoneally purified from lymph node cells of either naive or ovalbumin (OVA)-sensitized rats and were challenged with aerosolized OVA 2 days later. Control rats were sensitized to 100 mug of OVA in Al(OH) 3 subcutaneously or sham sensitized to saline and were OVA challenged 2 weeks later. RESULTS: The OVA-sensitized and OVA-challenged group and the recipients of OVA-primed CD8+ alphabeta T cells had significant late airway responses calculated from lung resistance measured for an 8-hour period after challenge compared with the naive CD8 + alphabeta T cell-transferred group and the sham-sensitized control group. The number of eosinophils in bronchoalveolar lavage fluid increased in the OVA-sensitized group and the OVA-primed CD8+ alphabeta T-cell recipients compared with numbers in the naive CD8+ alphabeta T-cell recipients and the sham-sensitized control group. IL-4 and IL-5 cytokine mRNA expression in bronchoalveolar lavage fluid increased in the OVA-sensitized group and the OVA-primed CD8+ alphabeta T-cell recipients compared with that in the sham-sensitized group. CONCLUSION: We conclude that antigen-primed CD8 + alphabeta T cells might have a proinflammatory role in allergen-driven airway responses in the rat.
Chronic obstructive pulmonary disease (COPD) is a progressive and irreversible chronic inflammatory disease of the lung. The nature of the immune reaction in COPD raises the possibility that IL-17 and related cytokines may contribute to this disorder. This study analyzed the expression of IL-17A and IL-17F as well as the phenotype of cells producing them in bronchial biopsies from COPD patients.
Bronchoscopic biopsies of the airway were obtained from 16 COPD subjects (GOLD stage 1-4) and 15 control subjects. Paraffin sections were used for the investigation of IL-17A and IL-17F expression in the airways by immunohistochemistry, and frozen sections were used for the immunofluorescence double staining of IL-17A or IL-17F paired with CD4 or CD8. In order to confirm the expression of IL-17A and IL-17F at the mRNA level, a quantitative RT-PCR was performed on the total mRNA extracted from entire section or CD8 positive cells selected by laser capture microdissection.
IL-17F immunoreactivity was significantly higher in the bronchial biopsies of COPD patients compared to control subjects (P
BACKGROUND: Gamma-delta (gammadelta) T cells regulate immune responses to foreign protein at mucosal surfaces. Whether they can modify allergen-induced early (EAR) and late airway responses (LAR) is unknown. OBJECTIVE: We have tested the hypothesis that the CD8+ subtype of gammadelta T cells decreases allergen-induced LAR and airway eosinophilia in the rat. METHODS: Brown Norway rats were administered, intraperitoneally, 3.5 x 10(4) lymph node CD8+gammadelta T cells from naive or sensitized rats. The recipients were sensitized to ovalbumin (OVA) in Al(OH)(3) 3 days after cell transfer and challenged with aerosolized OVA 14 days later. Serum IgE was measured before allergen challenge. After challenge, lung resistance was monitored for 8 hours and then bronchoalveolar lavage (BAL) was analyzed for eosinophil major basic protein (MBP), IL-4, IL-5, IL-13, and IFN-gamma messenger RNA-expressing cells. RESULTS: gammadelta T cells from naive donors significantly decreased LAR in OVA-challenged sensitized rats, whereas MBP(+) eosinophils were decreased by both gammadelta T cells from naive and sensitized donors. EAR and serum IgE levels were unchanged. The expression of IL-4, IL-5, and IL-13 by BAL cells of gammadelta T cell recipients was attenuated compared with OVA-challenged controls. This was accompanied by an increase in the expression of IFN-gamma. CONCLUSIONS: Our results are consistent with a suppressive role of CD8+gammadelta T cells on allergic airway responses. However, only gammadelta T cells from naive donors inhibit LAR.
BACKGROUND: There is evidence that the cytokine IL-5 is a prominent feature of airway inflammation in asthma. OBJECTIVE: The aim of this study was to determine whether exogenous IL-5 could cause changes in lung physiology, the early and late airway response after antigen challenge, and airway inflammation in rats that do not have a propensity to develop these changes after sensitization and challenge. METHOD AND RESULTS: Intratracheal administration of IL-5 to ovalbumin sensitized Brown Norway SSN rats increased the airway responsiveness to methacholine (AHR) 20 hours after administration of IL-5 at the same time as an increase in neutrophils occurred in the lung lavage. This effect was dose dependent and was not caused by endotoxin. Concurrent intratracheal administration of 50 ng of anti-IL-5 monoclonal antibody with 10 microg of recombinant human IL-5 decreased the AHR and neutrophil influx. Pretreatment with 3 microg of IL-5 had no effect on the early and late airway response or on AHR after ovalbumin challenge. However, IL-5 increased lung re-sistance 20 hours after antigen challenge. Although total lung cells and differential counts did not differ significantly 8 hours after antigen challenge, the blood lymphocyte CD4/CD8 ratio decreased in IL-5 pretreated rats (P
Heaves is a common condition of horses of cold climate that is characterized by small airway inflammation and obstruction following exposure of susceptible horses to moldy hay and straw. It has been shown that helper T lymphocytes (Th) orchestrate the inflammatory response in asthma and in various animal models of allergic lung diseases by the release of Th2-type cytokines. Results of previous studies indicate that a predominant expression of Th2-type response by airway cells may also be present in heaves. To evaluate the temporal mRNA expression of Th1 (IFN-gamma) and Th2 (IL-4, IL-5) type cytokines in heaves and their relationship to clinical disease, we studied the pulmonary mechanics and cytokine mRNA expression (IL-4, IL-5 and IFN-gamma) in bronchoalveolar lavage lymphocytes of horses with heaves (n=6) and control (n=6) before and after 24h and 9 days of continuous natural inhalation challenge. Starting 24h after challenge horses with heaves, but not control horses, had a significant increase in pulmonary elastance and the number of lymphocytes expressing mRNA for IL-4 and IL-5. These changes were further increased at 9 days, at which time the number of cells positive for IFN-gamma mRNA was decreased. In this study we have shown that BAL lymphocytes of horses with heaves during clinical exacerbation have a predominant Th2-type cytokine response and that this response coincides in time with the presence of airway obstruction.
BACKGROUND: The role of CD8+ T cells in the immune response to airway challenge with an allergen is poorly understood. OBJECTIVE: The aim of this study was to test the hypothesis that resident naive CD8+ T cells modulate the magnitude of CD4+ T cell-dependent allergic airway responses. METHODS: Cervical lymph node CD4+ T cells (2 x 10(6)) were harvested from ovalbumin (OVA)- or sham-sensitized rats and injected intraperitoneally into naive Brown Norway recipients. The recipients were treated with a CD8alpha mAb (OX-8) to deplete the resident CD8+ T cells (n = 12) or mouse ascites (n = 12). Two days after adoptive transfer, the recipient animals were OVA challenged, lung resistance was measured for 8 hours, and bronchoalveolar lavage (BAL) was performed. RESULTS: After OVA challenge, primed CD4-transferred CD8-depleted rats had larger early airway responses and late airway responses compared with primed CD4-transferred CD8-nondepleted rats (early airway responses: 158.6% +/- 19.2% vs 115.7% +/- 5.9%, P