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Eosinophils are classically known as proinflammatory cells, as they are equipped with a variety of preformed cytotoxic mediators and have been shown to definitively contribute to asthma. The connection between eosinophils and asthma development has led to a new class of asthma therapeutics based on blocking eosinophils with humanized antibodies that neutralize IL-5, a potent eosinophil growth, activation, and survival factor. Yet, recent studies have led to an increasing appreciation that eosinophils have a variety of homeostatic functions, including immunomodulation. In this issue of the JCI, Mesnil et al. identify a notable population of lung-resident eosinophils and demonstrate that, compared with traditional eosinophils, these cells have distinct characteristics, including nuclear structure, surface markers, IL-5 independence, and immunoregulatory function that is capable of polarizing adaptive immune responses, at least in vitro. Thus, these results reinforce a key homeostatic role for this enigmatic cell population, particularly in residing and regulating immunity in the lung., Eosinophils: traditionally proinflammatory Eosinophils are traditionally viewed as proinflammatory cells, as they are equipped with a variety of preformed cytotoxic mediators, including the granule proteins major basic protein (MBP) and [...]

The ability of corticosteroids to reduce airway inflammation and improve lung function is significantly reduced in asthmatics who are tobacco smokers compared with asthmatics who are nonsmokers. As not only high levels of tobacco smoke exposure in active smokers, but also significantly lower levels of tobacco smoke exposure from passive environmental tobacco smoke (ETS) exposure in nonsmokers can increase both asthma symptoms and the frequency of asthma exacerbations, we utilized a mouse model to determine whether corticosteroids can reduce levels of airway inflammation, airway remodeling, and airway hyperreactivity in mice exposed to the combination of chronic ETS and ovalbumin (OVA) allergen. Chronic ETS exposure alone did not induce increases in eosinophilic airway inflammation, airway remodeling, or airway hyperreactivity. Mice exposed to chronic OVA allergen had significantly increased levels of peribronchial fibrosis, increased thickening of the smooth muscle layer, increased mucus, and increased airway hyperreactivity, which was significantly enhanced by coexposure to the combination of chronic ETS and chronic OVA allergen. Administration of corticosteroids to mice exposed to chronic ETS and OVA allergen significantly reduced levels of eosinophilic airway inflammation, mucus production, peribronchial smooth muscle thickness, airway hyperreactivity, and the number of peribronchial TGF-[beta]1 + cells. Overall, this study demonstrates that corticosteroids can significantly reduce levels of eosinophilic inflammation, mucus expression, airway remodeling, and airway hyperreactivity in chronic ETS-exposed mice challenged with allergen. allergy; eosinophils

Although anticholinergic therapy inhibits bronchoconstriction in asthmatic patients and antigen-challenged animals, administration of atropine 1 h before antigen challenge significantly potentiates airway hyperreactivity and eosinophil activation measured 24 h later. This potentiation in airway hyperreactivity is related to increased eosinophil activation and is mediated at the level of the airway nerves. Since eosinophils produce nerve growth factor (NGF), which is known to play a role in antigeninduced airway hyperreactivity, we tested whether NGF mediates atropine-enhanced, antigen challenge-induced hyperreactivity. Antibody to NGF (Ab NGF) was administered to sensitized guinea pigs with and without atropine pretreatment (1 mg/kg iv) 1 h before challenge. At 24 h after challenge, animals were anesthetized, vagotomized, paralyzed, and ventilated. Electrical stimulation of both vagus nerves caused bronchoconstriction that was increased in challenged animals. Atropine pretreatment potentiated antigen challenge-induced hyperreactivity. Ab NGF did not affect eosinophils or inflammatory cells in any group, nor did it prevent hyperreactivity in challenged animals that were not pretreated with atropine. However, Ab NGF did prevent atropine-enhanced, antigen challenge-induced hyperreactivity and eosinophil activation (assessed by immunohistochemistry). This effect was specific to NGF, since animals given control IgG remained hyperreactive. These data suggest that anticholinergic therapy amplifies eosinophil interactions with airway nerves via NGF. Therefore, therapeutic strategies that target both eosinophil activation and NGF-mediated inflammatory processes in allergic asthma are likely to be beneficial. anticholinergic; asthma; muscarinic receptors; parasympathetic nerves; neurotrophins

Eosinophil counts in the bronchoalveolar lavage fluid of wild-type (WT) mice increased after ovalbumin (OVA) challenge, a response that was diminished in comparably challenged low-expressing coagulation factor VII ([FVII.sup.tTA/tTA]) mice. Levels of T helper type 2 (Th2) cytokines, IL-4, IL-5, and IL-13, and eosinophil-attracting chemokines, eotaxin and RANTES, were also lower in the OVA-challenged [FVII.sup.tTA/tTA] mice. Eosinophils purified from low-FVII mice underwent apoptosis at a faster rate compared with WT eosinophils, and eosinophil migration in response to eotaxin was reduced in eosinophils obtained from [FVII.sup.tTA/tTA] mice. Airway hyperresponsiveness and mucous layer thickness were reduced in OVA-treated [FVII.sup.tTA/tTA] mice, and addition of exogenous coagulation factor X (FX) enhanced mucin production in human epithelial NCI-H292 cells. Correspondingly, incubation of FX with NCI-H292 cells resulted in activated (a) FX production, suggesting that the components required for FX activation were present on NCI-H292 cells. These results demonstrate that FVIIa functions in the asthmatic response to an allergen by stimulating lung eosinophilia, airway hyperresponsiveness, and mucin production, this latter effect through its ability to activate FX in conjunction with tissue factor. coagulation factor X; eosinophilia; T helper type 2 cytokines; chemokines; airway

Eosinophilic inflammation is a cornerstone of chronic asthma that often culminates in subepithelial fibrosis with variable airway obstruction. Pulmonary eosinophils (Eos) are a predominant source of TGF-[beta]1, which drives fibroblast proliferation and extracellular matrix deposition. We investigated the regulation of TGF-[beta]1 and show here that the peptidyl-prolyl isomerase (PPIase) Pin1 promoted the stability of TGF-[beta]1 mRNA in human Eos. In addition, Pin1 regulated cytokine production by both in vitro and in vivo activated human Eos. We found that Pin1 interacted with both PKC-[alpha] and protein phosphatase 2A, which together control Pin1 isomerase activity. Pharmacologic blockade of Pin1 in a rat asthma model selectively reduced eosinophilic pulmonary inflammation, TGF-[beta]1 and collagen expression, and airway remodeling. Furthermore, chronically challenged Pin1-/- mice showed reduced peribronchiolar collagen deposition compared with wild-type controls. These data suggest that pharmacologic suppression of Pin1 may be a novel therapeutic option to prevent airway fibrosis in individuals with chronic asthma., Introduction Persistent asthma is characterized by chronic pulmonary inflammation, which often culminates in airway fibrosis. The development of airway disease is referred to as remodeling and includes the deposition of [...]

INTRODUCTION: We investigated whether markers of airway and systemic inflammation, as well as heart rate variability (HRV) in asthmatics, change in response to fluctuations in ambient particulate matter (PM) in [...]

A PCR-based method was developed to detect Angiostrongylus cantonensis directly from molluscan tissue to control the outbreak of human eosinophilic meningitis.

Lymphopenia and restricted T cell repertoires in humans are often associated with severe eosinophilic disease and a T cell Th2 bias. To examine the pathogenesis of this phenomenon, C57BL/6 Rag2-/-mice received limited (3 x [10.sup.4]) or large (2 x [10.sup.6]) numbers of CD4 T cells. Three to 5 months after transfer, mice that had received 3 x [10.sup.4] T cells, but not those that received 2 x [10.sup.6], developed fulminant macrophage pneumonia with eosinophilia, Ym1 deposition, and methacholine-induced airway hyperresponsiveness, as well as eosinophilic gastritis; esophagitis and other organ damage occurred in some cases. Donor cells were enriched for IL-4, IL-5, and IL-13 producers. When 3 x [10.sup.4] cells were transferred into CD3[epsilon]-/-hosts, the mice developed strikingly elevated serum IgE. Prior transfer of 3 x [10.sup.5] CD25+ CD4 T cells into Rag2-/- recipients prevented disease upon subsequent transfer of CD25- CD4 T cells, whereas 3 x [10.sup.4] regulatory T cells (Tregs) did not, despite the fact that there were equal total numbers of Tregs in the host at the time of transfer of CD25- CD4 T cells. Limited repertoire complexity of Tregs may lead to a failure to control induction of immunopathologic responses, and limitation in repertoire complexity of conventional cells may be responsible for the Th2 phenotype. eosinophils | IgE ILL-4 | macrophages | pneumonia

Asthma is one of the leading causes of childhood hospitalization, and its incidence is on the rise throughout the world. Currently, the standard treatment for asthma is the use of corticosteroids to try to suppress the inflammatory reaction taking place in the bronchial tree. Using a murine model of atopic allergic asthma employing a methacholine-hyperresponsive (A/J) as well as a hyporesponsive (C57BL/6) strain of mice sensitized and challenged with ovalbumin, we show that treatment with a synthetic Toll-like receptor 7 (TLR7) ligand (S-28463, a member of the imidazoquinoline family) prevents development of the asthmatic phenotype. Treatment with S-28463 resulted in a reduction of airway resistance and elastance following ovalbumin sensitization and challenge. This was accompanied by a dramatic reduction in infiltration of leukocytes, especially eosinophils, into the lungs of both C57BL/6 and A/J mice following OVA challenge. Treatment with S-28463 also abolished both the elevation in serum IgE level as well as the induction of IL-4, IL-5, and IL-13 by OVA challenge. The protective effects of S-28463 were also observed in MK2 knockout, but not MYD88 knockout, mice. We did not observe a switch in cytokine profile from [T.sub.H]2 to [T.sub.H]1, as both 1L-12p70 and IFN-[gamma] levels were reduced following S-28463 treatment. These results clearly demonstrate the anti-inflammatory effect of imidazoquinolines in an allergic asthma model as well as the clinical potential of TLR7 ligands in the treatment of allergic diseases. Toll-like receptors; asthma; eosinophils; lung; inflammation; mitogen-activated protein kinase-activated protein-2

Although leukocytes of the innate immune system, including eosinophils, contain within their granules preformed stores of cytokines available for selective and rapid release, little is known about the mechanisms governing the mobilization and secretion of these cytokines. Here we show that a cytokine receptor, the IL-4 receptor [alpha] chain, mediates eotaxin-stimulated mobilization of preformed IL-4 from eosinophil granules into secretory vesicles. Eosinophils contain substantial intracellular quantities of several granule- and vesicle-associated cytokine receptors, including IL-4, IL-6, and IL-13 receptors as well as CCR3. Both IL-4 and IL-4 receptor [alpha] chain colocalized in eosinophil granules; and after eotaxin-stimulation, IL-4 receptor [alpha] chain, bearing bound IL-4, was mobilized into secretory vesicles. These findings indicate that intracellular cytokine receptors within secretory vesicles transport their cognate cytokines requisite for the secretion of cytokines preformed in innate immune leukocytes. intracellular cytokine receptor | intracellular cytokine trafficking piecemeal degranulation | vesicular transport

Abstract: The diagnosis of occupational asthma needs to be made objectively using as many criteria as possible. The latter include laboratory exposure tests with occupational agent(s), which are only available [...]

Mucosal eosinophils increase in a number of gastrointestinal diseases that are often associated with altered epithelial barrier function, including food allergic enteropathies and inflammatory bowel diseases. Although eosinophils are known to secrete biologically active mediators including granule proteins, their role in gastrointestinal diseases is uncertain. The aim of this study was to determine the impact of eosinophils on intestinal barrier function. Epithelial barrier function was determined in a coculture of eosinophils and T84 epithelial cells and in a routine model of T helper (Th) type 2-mediated colitis. Coculture conditions resulted in decreased transepithelial resistance (TER) and increased transepithelial flux. Cell-free coculture supematants contained a [greater than or equal to]5-kDa soluble factor that also diminished TER; these supernatants contained the eosinophil-granule proteins major basic protein (MBP) and eosinophil-derived neurotoxin (EDN). T84 barrier function decreased significantly when basolateral surfaces were exposed to native human MBP but not EDN. Additional studies identified downregulation of the tight junctional molecule occludin as at least one mechanism for MBP action. MBP-null mice were protected from inflammation associated with oxazolone colitis compared with wild-type mice. In conclusion, MBP decreases epithelial barrier function and in this manner contributes to the pathogenesis of inflammatory bowel diseases. tight junction; eosinophilic gastroenteritis; food allergy

Ozone hyperreactivity over 24 h is mediated by blockade of inhibitory [M.sub.2] muscarinic autoreceptors by eosinophil major basic protein. Because eosinophil populations in the lungs fluctuate following ozone, the contribution of eosinophils to [M.sub.2] dysfunction and airway hyperreactivity was measured over several days. After one exposure to ozone, [M.sub.2] function, vagal reactivity, smooth muscle responsiveness, and inflammation were measured in anesthetized guinea pigs. Ozone-induced hyperreactivity to vagal stimulation persisted over 3 days. Although hyperreactivity one day after ozone is mediated by eosinophils, AbVLA-4 did not inhibit either eosinophil accumulation in the lungs or around the nerves or prevent hyperreactivity at this time point. Two days after ozone, eosinophils in BAL, around airway nerves and in lungs, were decreased, and neuronal [M.sub.2] receptor function was normal, although animals were still hyperreactive to vagal stimulation. Depleting eosinophils with AbIL-5 prevented hyperreactivity, thus eosinophils contribute to vagal hyperreactivity by mechanisms separate from [M.sub.2] receptor blockade. Three days after ozone, vagal hyperreactivity persisted, eosinophils were again elevated in BAL in lungs and around nerves, and [M.sub.2] receptors were again dysfunctional. At this point, airway smooth muscle was also hyperresponsive to methacholine. Eosinophil depletion with AbIL-5, AbVLA-4, or cyclophosphamide protected [M.sub.2] function 3 days after ozone and prevented smooth muscle hyperreactivity. However, vagal hyperreactivity was significandy potentiated by eosinophil depletion. The site of hyperreactivity, muscle or nerve, changes over 3 days after a single exposure to ozone. Additionally, the role of eosinophils is complex; they mediate hyperreactivity acutely while chronically may be involved in repair. [M.sub.2] muscarinic receptors; vagus nerves

The visualization, by confocal Raman microscopy, of the intracellular distribution of two enzymes important in the immune eosinophil peroxidase (EPO) in eosinophils is reported. The effect of photobleaching of the Raman signal at 413.1 nm excitation on the reconstructed Raman images is discussed.

Byline: Karim Maghni (1), Francois Nantel (2), Chantal Lanoue (1), Solange Cloutier (1), Jean-Paul Cristol (1), Alain Cadieux (1), Pierre Sirois (1,2) Keywords: airway inflammation; hyperresponsiveness; eosinophil; guinea-pig Abstract: The effects of an intravenous injection of Sephadex beads on lung eosinophil infiltration and eosinophil peroxydase activity and its relationship to bronchial hyperresponsiveness was examined in guinea pigs. This Sephadex beads injection led to blood, lung and airway eosinophilia in association with bronchial hyperresponsiveness. Histologic examination of the lower bronchus indicated that the eosinophil number increased markedly in the mucosa and submucosa. In addition, the eosinophils surrounding the bronchioles 1 day after the Sephadex injection migrated further in airway submucosa and mucosa 7 and 14 days after. Moreover, the bronchial hyperresponsiveness is observed without histologic evidence of airway epithelium damage. Therefore, the bronchial hyperresponsiveness seems to be more related to the eosinophil infiltration in the airway epithelium and possibly eosinophil activation rather than to the eosinophil number recovered in the BAL fluid. We conclude that the maintenance of hyperresponsiveness state could be associated with the persistence of blood and airway eosinophilia. Author Affiliation: (1) Institute of Pharmacology of Sherbrooke, Medical School, University of Sherbrooke, Sherbrooke, P.Q., Canada, J1H 5N4 (2) IPS Pharma, 3001 North 12th Avenue, Sherbrooke, P.Q., Canada, J1H 5N4 Article History: Registration Date: 20/12/2004

The symptoms, and identification of eosinophilia are explained with the diagnosis report from a 12-year-old boy with fatigue and eosinophilia. The test report shows the presence of precursor B-cell acute lymphoblastic leukemia with eosinophilia and translocation.

Hypophalous acids (HOX), which are produced by activated neutrophils, monocytes, eosinophils and possibly macrophages are crucial for immune response. However, excessive or misplaced generation can damage host tissues.

The NADPH--oxidase is a plasma membrane enzyme complex that enables phagocytes to generate superoxide in order to kill invading pathogens, a critical step in the host defense against infections. The oxidase transfers electrons from cytosolic NADPH to extracellular oxygen, a process that requires concomitant [H.sup.+] extrusion through depolarization-activated [H.sup.+] channels. Whether [H.sup.+] fluxes are mediated by the oxidase itself is controversial, but there is a general agreement that the oxidase and [H.sup.+] channel are intimately connected. Oxidase activation evokes profound changes in whole-cell [H.sup.+] current ([I.sub.H]), causing an approximately--40-mV shift in the activation threshold that leads to the appearance of inward [I.sub.H]. To further explore the relationship between the oxidase and proton channel, we performed voltage-clamp experiments on inside-out patches from both resting and phorbol-12-myristate-13-acetate (PMA)-activated human eosinophils. Proton currents from resting cells displayed slow voltage-dependent activation, long-term stability, and were blocked by micromolar internal [[Zn.sup.2+]]. [I.sub.H] from PMA-treated cells activated faster and at lower voltages, enabling sustained [H.sup.+] influx, but ran down within minutes, regaining the current properties of nonactivated cells. Bath application of NADPH to patches excised from PMA-treated cells evoked electron currents ([I.sub.e]), which also ran down within minutes and were blocked by diphenylene iodonium (DPI). Run-down of both [I.sub.H] and [I.sub.e], was delayed, and sometimes prevented, by cytosolic ATP and GTP-[gamma]-S. A good correlation was observed between the amplitude of [I.sub.e] and both inward and outward [I.sub.H] when a stable driving force for [e.sup.-] was imposed. Combined application of NADPH and DPI reduced the inward [I.sub.H] amplitude, even in the absence of concomitant oxidase activity. The strict correlation between [I.sub.e] and [I.sub.H] amplitudes and the sensitivity of [I.sub.H] to oxidase-specific agents suggest that the proton channel is either part of the oxidase complex or linked by a membrane-limited mediator. KEY WORDS: physiology * NADPH-oxidase * zinc * phagocyte * patch-clamp

One immunological component of asthma is believed to be the interaction of eosinophils with parasympathetic cholinergic nerves and a consequent inhibition of acetylcholine muscarinic [M.sub.2] receptor activity, leading to enhanced acetylcholine release and bronchoconstriction. Here we have used an in vitro model of cholinergic nerve function, the human IMR32 cell line, to study this interaction. IMR32 cells, differentiated in culture for 7 days, expressed M2 receptors. Cells were radiolabeled with [[sup.3]H]choline and electrically stimulated. The stimulation-induced release of acetylcholine was prevented by the removal of [Ca.sup.2+]. The muscarinic [M.sub.1]/[M.sub.2] receptor agonist arecaidine reduced the release of acetylcholine after stimulation (to 82 [+ or -] 2% of control at [10.sup.-7] M), and the [M.sub.2] receptor antagonist AF-DX 116 increased it (to 175 [+ or -] 23% of control at [10.sup.-5] M), indicating the presence of a functional [M.sub.2] receptor that modulated acetylcholine release. When human eosinophils were added to IMR32 cells, they enhanced acetylcholine release by 36 [+ or -] 10%. This effect was prevented by inhibitors of adhesion of the eosinophils to the IMR32 cells. Pretreatment of IMR32 cells with 10 mM carbachol, to desensitize acetylcholine receptors, prevented the potentiation of acetylcholine release by eosinophils or AF-DX 116. Acetylcholine release was similarly potentiated (by up to 45 [+ or -] 7%) by degranulation products from eosinophils that had been treated with N-formyl-methionyl-leucyl-phenylalanine or that had been in contact with IMR32 cells. Contact between eosinophils and IMR32 cells led to an initial increase in expression of [M.sub.2] receptors, whereas prolonged exposure reduced [M.sub.2] receptor expression. adhesion molecule; [M.sub.2] receptor; asthma

The adhesion of eosinophils to nerve cells and the subsequent release of eosinophil products may contribute to the pathogenesis of conditions such as asthma and inflammatory bowel disease. In this study we have separately examined the consequences of eosinophil adhesion and degranulation for nerve cell morphology and development. Eosinophils induced neurite retraction of cultured guinea pig parasympathetic nerves and differentiated IMR32 cholinergic neuroblastoma cells. Inhibition of eosinophil adhesion to IMR32 cells attenuated this retraction. Eosinophil adhesion to IMR32 cells led to tyrosine phosphorylation of a number of nerve cell proteins, activation of p38 MAP kinase, and generation of neuronal reactive oxygen species (ROS). Inhibition of tyrosine kinases with genistein prevented both the generation of ROS in the nerve cells and neurite retraction. The p38 MAP kinase inhibitor SB-239063 prevented neurite retraction but had no effect on the induction of ROS. Thus eosinophils induced neurite retraction via two distinct pathways: by generation of tyrosine kinase-dependent ROS and by p38 MAP kinase. Eosinophils also prevented neurite outgrowth during differentiation of IMR32 cells. In contrast to their effect on neurite retraction, this effect was mimicked by medium containing products released from eosinophils and by eosinophil major basic protein. These results indicate that eosinophils modify the morphology of nerve cells by distinct mechanisms that involve adhesion and released proteins. inflammation; cell adhesion molecule; cholinergic nerve; major basic protein

Eosinophils are implicated prominently in allergic diseases and the host response to parasitic infections. Eosinophils may be activated in vitro by diverse classes of agonists such as immunoglobulins, lipid mediators, and cytokines. The leukocyte Ig-like receptors (LIRs) comprise a family of inhibitory and activating cell-surface receptors. Inhibitory MRs down-regulate cellular responses through cytoplasmic immunoreceptor tyrosine-based inhibitory motifs. There are limited data on the action of the activating LIRs, which are thought to signal through the Fc receptor [gamma] chain, which contains an immunoreceptor tyrosine-based activation motif. We now demonstrate the expression of LIR1 (inhibitory), LIR2 (inhibitory), LIR3 (inhibitory), and LIR7 (activating) on eosinophiis from 4, 4, 12, and 11, respectively, of 12 healthy donors. Cross-linking of LIR7 with plate-bound antibody elicited the dose- and time-dependent release of eosinophil-derived neurotoxin and leukotriene [C.sub.4]. Eosinophils activated with antibodies to LIR7 embedded in gelphase EliCell preparations showed leukotriene [C.sub.4] generation at the nuclear envelope and the release of IL-12 but not IL-4 by vesicular transport. Thus, LIR7 is an activating receptor for eosinophils that elicited the release of cytotoxic granule proteins, de novo lipid mediator generation, and cytokine release through vesicular transport.

Byline: N. Saito (), Y. Yamada (), S. Sannohe (), K. Honda (), T. Adachi (), H. Kayaba (), J. Chihara () Abstract: Adhesion molecules and C-C chemokines play an important role in the accumulation of eosinophils in allergic inflammation. In the present study, the expression and function of adhesion molecules on eosinophils from asthmatic patients and involvement of RANTES and eotaxin were examined. Eosinophils isolated by the CD16 negative selection method were stimulated with or without RANTES or eotaxin. Expression of b integrins on eosinophils and the functional adherence to recombinant soluble intercellular adhesion molecule-1 (r-sICAM-1)-coated plates were examined. Compared with normal subjects, eosinophils from asthmatic patients showed increased expression of b2 integrins and functional adherence to r-sICAM-1-coated plates. RANTES and eotaxin augmented the functional adherence of eosinophils without a significant upregulation of b2 integrins. Anti-b2 integrin antibody inhibited the augmentative effect on eosinophil adherence of RANTES and eotaxin. Pertussis toxin, wortmannin, and genistein inhibited chemokine-induced adherence. RANTES and eotaxin are closely related to eosinophil accumulation not only as chemotactic agents but also as augmentative agents for eosinophil adherence through involvement in functional eosinophil adherence to ICAM-1 by a possible qualitative change of b2 integrins. Pertussis toxin-sensitive G proteins, PI3 kinase, and tyrosine kinase are involved in signal transduction leading to activation of b2 integrins on eosinophil following stimulation with RANTES and eotaxin. Author Affiliation: () Department of Clinical and Laboratory Medicine, Akita University School of Medicine, 1-1-1 Hondo, Akita, Japan 010-8543, JP Article History: Accepted Date: 13/08/2002

Asthma is a major medical problem but, despite decades of research, the mechanisms that underlie this condition remain elusive. Although the eosinophil has been regarded as a cell that is central to the pathogenesis of asthma, the failure to abrogate asthma symptoms by novel treatments that are designed to suppress the recruitment of eosinophils to the airways challenges this dogma. Our approach to understanding bronchial asthma needs to be broadened to include alterations in the function of afferent nerves that supply airways. Changes in the activity of these nerves offer a possible mechanism by which asthmatic subjects are uniquely responsive to a wide range of physiological and chemical stimuli. Here, we review the current status of asthma research.

Byline: Elizabeth Kudlacz (1), Carrie Whitney (1), Catharine Andresen (1), Maryrose Conklyn (1) Keywords: Eosinophil; chemokine; lung; rodent; eotaxin; adhesion molecules Abstract: Synergistic interactions between cytokines, chemokines and adhesion molecules may facilitate the selective recruitment of eosinophils into sites of allergic inflammation. Ovalbumin-sensitized IL5TG mice responded to antigen challenge with robust airway eosinophilia 24 and 72 hr post-exposure. Adhesion molecule expression and functional responsiveness of immune cells derived from IL5TG mice to various inflammatory mediators were evaluated. IL5TG-derived eosinophils, but not neutrophils, expressed higher levels of CD49d and CD11b relative to WT. Functional responsiveness to eotaxin was increased in IL5TG eosinophils as demonstrated by a 10x increase in its potency in producing actin polymerization and 3x increase in CD11b upregulation relative to WT. These data are consistent with increased CCR3 expression on IL5TG eosinophils. Responsiveness of eosinophils to LTB4 or MIP-1[alpha] was similar between WT and IL-5TG mice. These data provide evidence of synergy between eosinophil-specific cytokines and chemokines that may promote accumulation of this cell type under conditions of allergic inflammation in vivo. Author Affiliation: (1) Pfizer Global Research and Development, Eastern Point Road, Groton, CT, 06340 Article History: Registration Date: 12/10/2004

Byline: K. Fujimoto (), T. Tsunoda (), T. Koizumi (), K. Kubo () Abstract: Eosinophils have been shown to play a role in allergen-induced airway responses. The aim in this study was to examine the effects of TAK-661, a newly developed product as a specific inhibitory agent of eosinophil chemotaxis, on antigen-induced asthmatic responses in allergic sheep model. Seven Ascaris-sensitive, "dual-respondent" allergic sheep were provocated by an Ascaris suum antigen or phosphate-buffered saline 2 hrs after intra-stomach administration of TAK-661 or a placebo. Pulmonary resistances were measured throughout the experiment, and airway responsiveness to methacholine, bronchoalveolar lavage (BAL), and histological examination were performed 8 hrs after the antigen challenge. Antigen provocation induced dual-phase bronchoconstriction, eosinophilia in BAL and eosinophil infiltration into the airway wall, and an increase in airway responsiveness in placebo-treated sheep. The administration of TAK-661 significantly reduced the bronchoconstriction during the late phase, along with the inhibition of eosinophilia in BAL and the eosinophil infiltration into the airway wall. TAK-661 had a tendency to reduce early-phase bronchoconstriction and airway hyperresponsiveness, but there were no significant differences. These findings suggest that the eosinophil accumulation into the airway induced by antigen provocation may contribute to the development of late-phase bronchoconstriction, however, the development of airway hyperresponsiveness during late asthmatic response may not always be due to only eosinophilic inflammation in the airway. Author Affiliation: () The First Department of Internal Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390 Japan, JP Article History: Accepted Date: 23/04/2002

Byline: J. Gregory Noel (1), Denise A. Wells (1), Xialing Guo (1), Fansheng Kong (2), Glenda J. Lovell (1), Cora K. Ogle (1,2) Keywords: Thermal injury; myelopoiesis; eosinophils; GM-CSF; IL-5 Abstract: We have investigated the effects of thermal injury upon myelopoiesis. IL-3, GM-CSF, and IL-5 were used to stimulate myeloid colony formation. IL-3 induces early myeloid progenitors and a more developed myeloid progenitor, the granulocyte-macrophage colony-forming unit (GM-CFU), to multiply and develop into mature myeloid cells. GM-CSF induces GM-CFU to become mature myeloid cells, while IL-5 induces eosinophil progenitors to become mature eosinophils. Stem Cell Factor (SCF) + IL-6 and FLT3 ligand, which have no effect on colony formation by themselves, were used to enhance the effects of IL-3 and GM-CSF, respectively. We found that thermal injury increased the number of early myeloid progenitors and GM-CFU in the spleen with either IL-3 or GM-CSF as a stimulant. Thermal injury increased the number of early myeloid progenitors in the bone marrow when GM-CSF, but not IL-3, was used to stimulate colony growth. Also, thermal injury increased the numbers of eosinophil progenitors in rat spleen and bone marrow and increased splenic levels of IL-5 mRNA. Author Affiliation: (1) Shriners Hospital for Children, Cincinnati, OH (2) Department of Surgery, University of Cincinnati, Cincinnati, OH Article History: Registration Date: 17/10/2004

Byline: K. Hara (1), T. Hasegawa (1), H. Ooi (1), T. Koya (1), Y. Tanabe (1), H. Tsukada (1), K. Igarashi (1), E. Suzuki (1), M. Arakawa (1), F. Gejyo (1) Keywords: Key words: Eosinophil--Transforming growth factor [beta]--Plasmin--Plasminogen activator--Bronchial asthma. Abstract: Eosinophilic bronchitis is an essential component of bronchial asthma, and eosinophils play an important role. We studied the effect of eosinophils on cell surface plasmin generation by bronchial epithelial cells, because plasmin is thought to be involved in bronchial tissue repair/remodeling by means of fibrinolysis and the activation of proteases such as matrix metalloproteases. Plasmin was generated from exogenous plasminogen on the cell surface of cultured bronchial epithelial cells, NCI-H292. Transforming growth factor [beta] (TGF-[beta]) treatment resulted in reduced cell surface plasmin generation and a large increase in plasminogen activator inhibitor-type 1 (PAI-1) antigen production in NCI-H292 cells, whereas no conspicuous effects were observed with IL-1[beta] and TNF[alpha] treatment (regulators in pulmonary epithelial cells). On the other hand, this cell surface plasmin generation was reduced by co-incubation with Eol-1, an eosinophil cell line. The addition of TGF-[beta] antisense and anti-TGF-[beta] antibodies attenuated this adverse effect of Eol-1 cell co-incubation. These data suggest that eosinophils play an inhibitory role on cell surface plasmin generation by bronchial epithelial cells by means of the up-regulation of PAI-1 expression induced by TGF-[beta]. Therefore, the accumulation of eosinophils in bronchial walls is thought to be involved in bronchial tissue repair/remodeling in asthma through this protease network. Author Affiliation: (1) Department of Medicine (II), Niigata University School of Medicine, Niigata, Japan, JP Article note: Accepted for publication: 10 January 2001

Byline: David M. Hammerbeck (1), Sean M. Mcgurran (1), Pam L. Radziszewski (1), Elaine A. Egging (1), David D. Johnson (1), Ann M. Hupperts (1), Gary W. Gullikson (1) Abstract: Representative glucocorticosteroids (GCS) and phosphodiesterase IV (PDE4) inhibitors were compared in several models of pulmonary inflammation ranging in severity. Lung tissue eosinophil peroxidase (EPO) levels rather than bronchoalveolar lavage fluid (BALF) EPO or eosinophil percentages were used to indicate eosinophil recruitment after intratracheal instillation of sephadex beads in rats or nebulized ovalbumin in sensitized guinea pigs. A single oral or intratracheal administration of a GCS was effective against mild and robust sephadex-induced eosinophilia whereas the PDE.sub.4 inhibitors evaluated appeared more effective in the milder sephadex models. The GCS were also more effective against sephadex-induced than ovalbumin-induced eosinophilia. The effectiveness of the GCS and PDE.sub.4 inhibitors improved when the severity of the ovalbumin-induced eosinophilia was decreased. Multiple day dosing also improved activity. These studies indicated that activity was influenced greatly by administration protocols, the severity of the inflammatory response and possibly the method used for estimating eosinophil recruitment. Author Affiliation: (1) 3M Pharmaceuticals, 3M Company, St. Paul, Minnesota, 55144 Article History: Registration Date: 09/10/2004

Byline: Eva Fernvik (1), Joachim Lundahl (1), Gunilla Hallden (1) Abstract: Eosinophils accumulate at sites of allergic inflammation, and play important roles in asthma/allergic disorders. The mechanism of eosinophil recruitment into tissues is not fully understood. In this study, we evaluated whether adhesion and/or transmigration, in the presence of IL-5 and eotaxin, alter the expression of CD9, CD11b, the [beta].sub.1[alpha].sub.4-integrin, and the EG2-epitope on intracellular ECP. We also investigated whether CD9 is involved in the adhesion process. With flow cytometry the surface expression of CD9, CD11b and the [beta].sub.1[alpha].sub.4-integrin, and the intracellular expression of EG2, were analyzed before, and after transmigration/adhesion to fibronectin. To evaluate the eventual role of CD9 in adhesion, eosinophils were preincubated with monoclonal antibodies to CD9. We observed decreased expression of CD9, and increased expression of CD11b on eosinophils, after adhesion and transmigration. The transmigration did not change the expression of the [beta].sub.1[alpha].sub.4-integrin or EG2, whereas the adhesion resulted in a decreased EG2 expression. Antibodies to CD9 decreased the adhesion property of eosinophils. The eosinophils are activated after both adhesion and transmigration by means of decreased CD9 and increased CD11b expression. The expression of the EG2-epitope on intracellular ECP was decreased when eosinophils adhered to fibronectin, probably due to degranulation. Our results also indicate that CD9 is involved in the adhesion of eosinophils to fibronectin. Author Affiliation: (1) Department of Laboratory Medicine, Division of Clinical Immunology, Karolinska Hospital and Institute, Stockholm, Sweden Article History: Registration Date: 09/10/2004

The Charcot-Leyden crystal (CLC) protein has been one of the most interesting subjects of biochemistry research due to its undetermined link with eosinophil functions. Diffraction data derived from a sample of CLC cyrstals, however, suggest that these proteins do not actually have affinity for beta-galactosides. Results further indicate that CLC proteins bind with mannose in a manner distinct with other galectin compounds.

Byline: S. Lantero (1), S. Oddera (1), M. Silvestri (1), R. Gonzalez Rodriguez (1), M. C. Morelli (2), G. A. Rossi (1) Keywords: Key words: Allergic asthma--T-lymphocytes--Cytokines--Granulocytes--Chemotaxis--Interleukin-5--Corticosteroids. Abstract: Treatment of allergic asthma with inhaled corticosteroids results in local down-regulation of proinflammatory cytokine synthesis and in marked decrease in tissue eosinophilia. Blood concentrations of inhaled corticosteroids, although significantly lower than those measured in the lung, may still have antiinflammatory effects on circulating eosinophils, reducing their ability to migrate. The aim of our study was to evaluate in vitro the activity of budesonide on blood eosinophils by measuring their chemotactic response, eosinophil cationic protein (ECP) release, and hydrogen peroxide ([H.sub.2]O.sub.2) production in the presence of different drug concentrations similar to those obtained at airway level (10.sup.-8 and 10.sup.-7 M) and at blood level (10.sup.-10 and 10.sup.-9 M). Partially purified blood eosinophils, isolated from 23 asthmatic subjects, were used to evaluate the activity of budesonide on: (1) chemotaxis toward the activated fifth component of complement (C5a, 0.1 ug/ml) or recombinant human (rh) interleukin (IL)-5 (200 pg/ml), (2) ECP release by cells stimulated with tetradecanoylphorbol acetate (TPA) and (3) [H.sub.2]O.sub.2 production by TPA-activated cells. The chemotactic response to C5a was down-regulated significantly by budesonide only by the highest concentrations tested (10.sup.-8 and 10.sup.-7 M) differently, budesonide was effective in inhibiting eosinophil migration toward rhIL-5, at all concentrations tested (p &lt 0.01, each comparison). By contrast, no drug-induced modifications were observed in ECP release or in [H.sub.2]O.sub.2 production (p &gt 0.05, each comparison). We conclude that concentrations of budesonide similar to those obtained in vivo are effective in inhibiting eosinophil locomotion but not in down-regulating the release of reactive oxygen species and granule-associated proteins. Author Affiliation: (1) Pulmonary Division, G. Gaslini Institute, Genoa, Italy, IT (2) Astra Farmaceutici, Milan, Italy, IT Article note: Accepted for publication: 11 February 1999

Eosinophils are known to play a vital role in allergic conditions such as asthma. Their action is linked to the release of cytotoxic proteins and other mediators that trigger hyperreactivity in respiratory muscle cells. Eosinophils have also been shown to increase phosphatidylcholine (PC) secretion in primary cultures of rat type II pneumocytes. Further examination of the role of eosinophil major basic protein (MBP) shows that MBP induces PC secretion and provides mechanical stability in rat type II pneumocytes, thereby helping to protect against lung atelectasis.

Byline: S. Oddera (1), M. Silvestri (1), R. Penna (2), G. Galeazzi (2), E. Crimi (3), G. A. Rossi (1) Keywords: Key words: Eosinophils--Eosinophil cationic protein--Asthma--Atopy--Bronchial hyperresponsiveness--Methacholine--Bronchoalveolar lavage--Inflammation. Abstract: Allergen exposure in atopic asthmatic patients is associated with recruitment and activation of eosinophils in the airways. Once activated, eosinophils release toxic products, including the eosinophil cationic protein (ECP), able to damage bronchial structures and to increase bronchial hyperresponsiveness. With this background, the present study was designed to evaluate whether ECP levels in bronchoalveolar lavage (BAL) fluid could reflect, better than BAL eosinophil counts, the cellular activation that follows allergen exposure in atopic asthmatics. Twenty-two atopic patients attended the laboratory on two separate days. On the 1st day, they underwent methacholine (MCh) inhalation challenge to detect the degree of nonspecific bronchial hyperresponsiveness. On the 2nd day, they underwent fiberoptic bronchoscopy and BAL, at baseline or 4--6 h after allergen inhalation challenge. In this latter patient group, MCh challenge was repeated 3--5 h after allergen challenge, 1 h before fiberoptic bronchoscopy. The analysis of the mean baseline FEV.sub.1 values and the degree of bronchial reactivity to MCh (MCh Pd.sub.20) on the 1st study day did not demonstrate differences between the two patient groups (p &gt 0.1, each comparison). In addition, in the allergen-challenged group, MCh Pd.sub.20 was decreased significantly after allergen challenge (151.4 ug/ml and 67.6 ug/ml, respectively, before and after challenge p &lt 0.05). Evaluation of the different BAL cell types demonstrated that the proportions of eosinophils and epithelial cells were increased significantly in the allergen-challenged group compared with the group evaluated at baseline (p &lt 0.01 and p &lt 0.05, respectively). Moreover, ECP levels, corrected by the correspondent albumin levels (ECP/Alb), were higher in the allergen-challenged group compared with the group evaluated at baseline (p &lt 0.05). In addition, although a positive correlation was demonstrated between BAL eosinophil percentages and ECP/Alb values (r= 0.72, p &lt 0.05) in the group evaluated at baseline, no links were found between these parameters in the allergen-challenged group (p &gt 0.1). However, in this latter group, a weak positive correlation was demonstrated between eosinophil percentages and IMch, i.e., the increased nonspecific bronchial reactivity, which is observed after allergen challenge (r= 0.55 p &lt 0.05). Thus, in stable asthmatic patients an ongoing activation of eosinophils parallels their migration, but this eosinophilic inflammation is not strictly related to bronchial reactivity to Mch. By contrast, after allergen inhalation challenge, eosinophil recruitment and activation seem to follow different temporal kinetics, and eosinophilic inflammation may be partially associated with the degree of airway hyperresponsiveness. Author Affiliation: (1) Divisione di Pneumologia, Istituto G. Gaslini, Universita di Genova, Genova, Italy, IT (2) Laboratorio di Analisi, Istituto G. Gaslini, Universita di Genova, Genova, Italy, IT (3) Cattedra di Fisiopatologia Respiratoria, Universita di Genova, Genova, Italy, IT Article note: Accepted for publication: 15 September 1997

Byline: Joachim Lundahl (1), Ali Moshfegh (1), Reidar Gronneberg (2), Gunilla Hallden (1) Abstract: A selective recruitment of eosinophils to sites of inflammation is claimed to be controlled by regulation of cytokines, chemokines and adhesion molecules. In animal models, eotaxin has been suggested to be a potent chemokine since it in cooperation with interleukin-5 induce selective chemotaxis and infiltration of eosinophils to lung tissue after an allergen provocation. We have investigated the in vitro effect of eotaxin on human peripheral blood eosinophils with respect to CD11b/CD18 expression and adhesion properties to the matrix protein fibronectin. We did not find any effect of eotaxin per se on CD11b/CD18 expression, neither on eosinophils from healthy subjects nor from patients with asymptomatic pollen related asthma. However, eotaxin significantly upregulated the quantitative level of CD11b/CD18 and increased the adhesion to fibronectin in eosinophils from healthy subjects preincubated in vitro with interleukin-5, but not in eosinophils preincubated with fMLP. Moreover, eosinophils harvested 24 hours after an in vivo allergen inhalation provocation in asthmatics, upregulated CD11b/CD18 after in vitro incubation with eotaxin alone. Author Affiliation: (1) Department of Laboratory Medicine, Division of Clinical Immunology, Karolinska Hospital, Sweden (2) Department of Medicine, Division of Respiratory and Allergic Diseases, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden Article History: Registration Date: 03/10/2004

Insights into structure-function relations of many proteins opens the possibility of engineering peptides to selectively interfere with a protein's activity. To facilitate the use of peptides as probes of cellular processes, we have developed caged peptides whose influence on specific proteins can be suddenly and uniformly changed by near-UV light. Two peptides are described which, on photolysis of a caging moiety, block the action of calcium-calmodulin or myosin light chain kinase (MLCK). The efficacy of theses peptides is demonstrated in vitro and in vivo by determining their effect before and after photolysis on activities of isolated enzymes and cellular functions known to depend on calcium-calmodulin and MLCK. These caged peptides each were injected into motile, polarized eosinophils, and when exposed to light promptly blocked cell locomotion in a similar manner. The results indicate that the action of calcium-calmodulin and MLCK, and by inference myosin II, are required for the ameboid locomotion of these cells. This methodology provides a powerful means for assessing the role of these and other proteins in a wide range of spatio-temporally complex functions in intact living cells.

Eosinophil migration in vivo is markedly attenuated in rats treated chronically with the NO synthase (NOS) inhibitor [N.sup.[Omega]]-nitro-L-arginine methyl ester (L-NAME). In this study, we investigated the existence of a NOS system in eosinophils. Our results demonstrated that rat peritoneal eosinophils strongly express both type II (30.2 [+ or -] 11.6% of counted cells) and type III (24.7 [+ or -] 7.4% of counted cells) NOS, as detected by immunohistochemistry using affinity purified mouse mAbs. Eosinophil migration in vitro was evaluated by using 48-well microchemotaxis chambers and the chemotactic agents used were N-formyl-methionyl-leucyl-phenylalanine (fMLP, 5 x [10.sup.-8] M) and leukotriene [B.sub.4] ([LTB.sub.4], [10.sup.-8] M). L-NAME (but not D-NAME) significantly inhibited the eosinophil migration induced by both fMLP (54% reduction for 1.0 mM; P < 0.05) and [LTB.sub.4] (61% reduction for 1.0 mM; P < 0.05). In addition, the type II NOS inhibitor 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine and the type I/II NOS inhibitor 1-(2-trifluoromethylphenyl) imidazole also markedly (P < 0.05) attenuated fMLP- (52% and 38% reduction for 1.0 mM, respectively) and [LTB.sub.4]- (52% and 51% reduction for 1.0 mM, respectively) induced migration. The inhibition of eosinophil migration by L-NAME was mimicked by the soluble guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3,-a] quinoxalin-1-one (0.01 and 0.1 mM) and reversed by either sodium nitroprusside (0.1 mM) or dibutyryl cyclic GMP (1 mM). We conclude that eosinophils do express NO synthase(s) and that nitric oxide plays an essential role in eosinophil locomotion by acting through a cyclic GMP transduction mechanism.

The CC chemokines regulated on activation normal T expressed and secreted (RANTES) and monocyte chemotactic protein 3 (MCP-3), and the anaphylatoxin C5a, induce activation, degranulation, chemotaxis, and transendothelial migration of eosinophils. Adhesion assays on purified ligands showed differential regulation of [Beta]1 and [Beta]2 integrin avidity in eosinophils. Adhesiveness of VLA-4 ([Alpha]4[Beta]1, CD29/CD49d) for vascular cell adhesion molecule 1 or fibronectin was rapidly increased but subsequently reduced by RANTES, MCP-3, or C5a. The deactivation of VLA-4 lead to cell detachment, whereas phorbol 12-myristate 13-acetate induced sustained activation of VLA-4. In contrast, chemoattractants stimulated a prolonged increase in the adhesiveness of Mac-1 ([Alpha]M[Beta]2, CD11b/CD18) for intercellular adhesion molecule 1. Inhibition by pertussis toxin confirmed signaling via G protein-coupled receptors. Chemoattractants induced transient, while phorbol 12-myristate 13-acetate induced sustained actin polymerization. Disruption of actin filaments by cytochalasins inhibited increases in avidity of VLA-4 but not of Mac-1. Chemoattractants did not upregulate a [Mn.sup.2+]-inducible [Beta]1 neoepitope defined by the mAb 9EG7, but induced prolonged expression of a Mac-1 activation epitope recognized by the mAb CBRM1/5. This mAb inhibited chemoattractant-stimulated adhesion of eosinophils to intercellular adhesion molecule 1. Thus, regulation of VLA-4 was dependent on the actin cytoskeleton, whereas conformational changes appeared to be crucial for activation of Mac-1. To our knowledge, this is the first demonstration that physiological agonists, such as chemoattractants, can differentially regulate the avidity of a [Beta]1 and a [Beta]2 integrin expressed on the same leukocyte.