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Background: Although eosinophils have been detected in several human skin diseases in the vicinity of basophils, how eosinophils infiltrate the skin and the role of eosinophils in the development of skin inflammation have yet to be examined., Objective: Using murine irritant contact dermatitis (ICD) as a model, we sought to clarify the roles of eosinophils in ICD and the underlying mechanism of eosinophil infiltration of the skin., Methods: We induced croton oil-induced ICD in eosinophil-deficient ΔdblGATA mice with or without a reactive oxygen species (ROS) inhibitor. We performed cocultivation with fibroblasts and bone marrow-derived basophils and evaluated eosinophil migration using a chemotaxis assay., Results: ICD responses were significantly attenuated in the absence of eosinophils or by treatment with the ROS inhibitor. ROS was produced abundantly by eosinophils, and both basophils and eosinophils were detected in human and murine ICD skin lesions. In coculture experiments, basophils attracted eosinophils, especially in the presence of fibroblasts. Moreover, basophils produced IL-4 and TNF-α in contact with fibroblasts and promoted the expression of eotaxin/CCL11 from fibroblasts in vitro., Conclusion: Eosinophils mediated the development of murine ICD, possibly through ROS production. Recruitment of eosinophils into the skin was induced by basophils in cooperation with fibroblasts. Our findings introduce the novel concept that basophils promote the recruitment of eosinophils into the skin through fibroblasts in the development of skin inflammation., (Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

The influence of a once-a-day sustained-release theophylline (Uniphyl) on lymphocytes and eosinophils in the peripheral blood and sputum of patients with bronchial asthma was investigated. The peripheral blood lymphocytes included CD4, CD8, CD25 and HLA-DR. The sputum lymphocytes and eosinophils included CD4, CD8, CD25 and HLA-DR, and EG2, respectively. The results revealed that theophylline administration did not affect the numbers of activated CD4 and CD8 T lymphocytes in peripheral blood. No significant change in the lymphocyte count was observed in sputum, but the eosinophil count in the sputum decreased significantly after theophylline administration. EG2-positive eosinophils also decreased in number. CD4+HLA-DR+ and CD4+CD25+ T lymphocytes were significantly decreased, whereas CD8+ T lymphocytes in the sputum were not significantly reduced in number. Respiratory function test showed that forced expiratory volume in 1 s was significantly increased after theophylline administration. The results suggest that a new once-a-day sustained-release theophylline formulation would be useful in the treatment of chronic respiratory tract inflammation.

The effects of an oral anti-allergic agent, TMK-688, which inhibits 5-lipoxygenase, at doses of 3.2 and 10 mg/kg were studied in guinea pigs with dual-phase asthmatic response. We previously observed that pretreatment with TMK-688 inhibited the late asthmatic response (LAR) induced by ovalbumin inhalation exposure. The present study focused on the effect of TMK-688 on infiltration by T-cells and eosinophils. TMK-688 inhibited both T-cell and eosinophilic infiltration. These findings suggest that TMK-688 is effective in inhibiting infiltration of T-cells and eosinophilic chemotaxis, and thereby suppresses LAR.

In recent years, bronchial asthma has come to be regarded as a chronic inflammatory disease of the respiratory tract, with mast cells, lymphocytes and eosinophils playing important roles in its pathogenesis. Proteins contained in eosinophil granules, especially major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN) and eosinophil peroxidase (EPO), can cause tissue injury. When stimulated, eosinophils release mediators such as leukotriene C4 (LTC4) and platelet activating factors (PAF). Thus, they are recognized as effector cells that are actively involved in the development of allergic inflammation. In this study, eosinophils from healthy volunteers were used to investigate the effects of Saiboku-to on eosinophils whose survival had been prolonged through stimulation with eosinophil-activating cytokines such as interleukin (IL)-3, IL-5 and granulocyte macrophage colony stimulating factors (GM-CSF). As a result, the cytokine-enhanced survival of eosinophils was significantly shortened by the addition of Saiboku-to. These findings suggest that Saiboku-to has the potential to inhibit allergic responses by directly affecting eosinophils which are related to allergic inflammation.

Background: Adhesion molecules may play an important role in eosinophilic activation as well as adherence of extracellular matrix (ECM) including fibronectin (FN) in the inflamed focus. Tissue eosinophils expressed inter-cellular adhesion molecule-1 (ICAM-1, CD54), whereas peripheral blood eosinophils did not. The molecular mechanisms of ICAM-1 expression on eosinophils are not clear. We immunologically examined the effect of adherence to FN on the expression of adhesion molecules in an eosinophilic cell line (EoL-1)., Methods: EoL-1 cells, suspended at a concentration of 2 x 10(6) cells/ml, were cultured at 37 degrees C in BSA or FN-coated 24-well plates. After 4 h, the cells were removed by pipetting, and the expression of adhesion molecules was evaluated by immunofluorescence., Results: Adherence of EoL-1 to FN enhanced ICAM-1 (CD54) expression on EoL-1 (FN vs. BSA: 84.76 +/- 17.90 vs. 43.73 +/- 7.60, mean fluorescent intensity). Regarding other adhesion molecules on EoL-1 (CD11a, CD18, CD49d), the expression was not significantly augmented by adherence to FN., Conclusions: We concluded that the signal via adhesion of FN regulates the expression of ICAM-1 on eosinophilic cells. This study suggests that eosinophilic adhesion to ECM via adhesion molecules plays an important role in the pathogenesis of allergic inflammation through eosinophilic functional changes, including regulation of expressive adhesion molecules such as ICAM-1.

It was recently reported that theophylline has an anti-inflammatory and bronchodilating effect on bronchial asthma. Accordingly, to examine the anti-inflammatory effect of theophylline on asthma, especially its effect on eosinophil activation, a sustained-release theophylline preparation (Theolong) was administered (daily dose: 400 mg) to 18 patients with mild to moderate bronchial asthma. This was done in order to study the preparation's effects on lung function, blood and sputum eosinophils and ECP four weeks pre- and post-administration. Lung function was determined by spirometry and sputum by induced sputum. Blood and sputum ECP levels were determined using an ECP RIA kit. In lung function, there were no differences in vital capacity (VC) or in forced expiratory volume 1 s (FEV 1.0) pre- and post-administration. There were also no differences in the number of blood and sputum eosinophils, but serum and sputum ECP levels decreased. Theophylline is thus expected to exert an inhibitory effect on eosinophil activation and it is suggested as an effective therapeutic drug for bronchial asthma.

Background: TMK688 is being developed as an anti-allergic drug having both 5-lipoxygenase inhibitory activity and anti-histamine activity., Method: We compared the inhibition of the late asthmatic responses by TMK688 with that by other anti-allergic agents in actively sensitized guinea pigs, and examined the relationship between 5-lipoxygenase inhibition and the late asthmatic responses., Results: At 1-3.2 mg/kg, TMK688 inhibited the increases in respiratory resistance, leukotriene (LT) B4 and C4 production in the lungs and eosinophil infiltration into the alveoli during the late asthmatic response, whereas the effects tended to lessen at the dose of 10 mg/kg. These effects are thought to be caused by the 5-lipoxygenase inhibitory activity of TMK688 because Azelastine, an anti-allergic drug having potent antihistamine activity, exhibited no effect. ONO-1078, a peptide LT antagonist, inhibited the late-phase bronchoconstriction at a dose of 100 mg/kg p.o., but not the increase in the infiltration of inflammatory cells into the alveoli, suggesting that the late-phase bronchoconstriction is induced, in part, by peptide LTs, i.e. LT C4, D4 and E4 and that the inflammatory cell infiltration may be caused by LTB4. TMK688 inhibited the immediate bronchoconstriction dose-dependently, and the effect was significant at a dose of 10 mg/kg orally. Since Azelastine, Ketotifen and Oxatomide suppressed the bronchoconstriction at far lower doses than did TMK688, the inhibitory effect was mainly caused by its antihistamine activity., Conclusions: TMK688 appears to be a novel anti-allergic drug having inhibitory effects on both the bronchoconstriction and the infiltration of inflammatory cells during late asthmatic responses.

The relationship between human T-lymphotropic virus I (HTLV-I) infection and strongyloidiasis has recently become an important problem. This study compared the expression of CD23, CD32, Mac-1 and other adhesion molecules in eosinophils of patients with strongyloidiasis positive for anti-(HTLV-I) antibodies and in those negative for the antibodies. The expression of CD23, Mac-1 and intercellular adhesion molecule-1 (ICAM-1) on eosinophils of patients with strongyloidiasis was augmented in comparison with normal subjects and HTLV-I carriers. There were no significant differences, however, in the expression of CD23, CD32, Mac-1 and adhesion molecules (ICAM-1, leukocyte function-associated antigen-1 alpha (LFA-1 alpha), LFA-1 beta, very late antigen-4) on eosinophils of patients with strongyloidiasis positive for anti-HTLV-I antibodies in comparison with those negative for these antibodies.

Fibronectin is an extracellular matrix (ECM) that binds to very late antigen-4 (a beta 1 integrin molecule) expressed by eosinophils. To investigate the effect of adherence to fibronectin on regulation of eosinophil cell death, survival of eosinophils was examined by trypan blue exclusion and Fas antigen expression on the cell surface using an eosinophilic cell line (EoL-1). Adhesion to fibronectin resulted in prolongation of eosinophil survival (fibronectin vs. bovine serum albumin (BSA), 62.9 +/- 5.10 vs. 53.9 +/- 4.30% viability at 72 h) and the decreasement of Fas antigen expression on EoL-1 (fibronectin vs. BSA, 24.3 +/- 2.15 vs. 74.5 +/- 8.25% positive). These findings suggest that eosinophil adhesion to ECM via adhesion molecules plays an important role in the pathogenesis of allergic inflammation, which involves eosinophil accumulation at the inflammatory site, through regulation of eosinophil cell death.

The cytokine RANTES (regulated on activation, normal T expressed and secreted) is a member of the platelet factor 4 superfamily and is a chemoattractant for eosinophils. To study the effect of RANTES on induction of activated eosinophils, flow cytometry was used to measure the expression of intracellular EG2 in eosinophils. The concentration of eosinophil cationic protein in the culture supernatant of eosinophils stimulated with RANTES was also measured. Expression of EG2 and the mean fluorescence intensity ratio were greater in eosinophils stimulated with RANTES than in control eosinophils. Eosinophils stimulated with RANTES also produced more eosinophil cationic protein than did control eosinophils.

Quinidine hydrochloride, as potent K+ channel blocker, reduced luminol-dependent chemiluminescence products evoked by the addition of the calcium ionophore A23187 to eosinophils from patients with hypereosinophilic syndrome (n = 3) in a concentration-dependent manner (10-5 mM quinidine). A23187 is known to cause increases in intracellular Ca2+ concentrations in eosinophils. Our results indicate that the production of reactive oxygen species by human eosinophils may be affected by Ca(+)-activated K+ channels.

To elucidate the mechanism for the accumulation of eosinophils through adherence in allergic inflammation, we investigate whether adhesion of eosinophils to extracellular matrix (ECM) regulates the expression of adhesion molecules on eosinophils. Highly purified eosinophils obtained from asthmatic patients were cultured on BSA or fibronectin (FN) coated plates for 4 or 48 hours. After then, removed cells were examined about the expression of each adhesion molecule. Cultured on FN resulted in the increment of the expressive CR 3 (CD11b) (BSA vs FN; MFI ratio 10.50 vs 12.09 p < 0.05), and decrement of the expressive VLA-4 (CD49d) on the eosinophils (3.93 vs 2.91 (4 h) p < 0.05, 2.86 vs 2.09 (48 h) p < 0.05). Thus, we could conclude that eosinophils adhesion to ECM via adhesion molecules might play an important role in the pathogenesis of allergic inflammation through the involvement in the regulation of the expression of adhesion molecules on eosinophils.

Adhesion molecules, particularly intercellular adhesion molecule-1 (ICAM-1), recently have been considered to play a key role in inflammatory processes in asthma. Thus, from the point of view of cell interactions between mononuclear cells and eosinophils, we examined whether the supernatant of mononuclear cells (MNC) obtained from mite-allergic asthmatic patients cultured with specific allergen is involved in ICAM-1 expression using an eosinophilic cell line (EoL). ICAM-1 expression was induced by the supernatant of MNC from mite-allergic asthmatic patients stimulated with mite allergen as well as by a combination of IL-3, GM-CSF, and IL-5. Thus, we could conclude that some cytokines produced by specific allergen-stimulated MNC in asthmatics might be involved in allergic inflammation through the induction of adhesion molecule expression such as ICAM-1 on eosinophils in asthma or allergic disorders.

Recently, adhesion molecules expressed on various inflammatory cells, especially on eosinophils are considered to play an important role in allergic inflammation such as bronchial asthma. RANTES (Regulated on activation normal T expressed and secreted) seems to be the most important chemokine which belongs to Platelet factor 4 (PF4) superfamily, since RANTES is revealed as a chemotactic factor for eosinophils as well as memory T cells or monocytes. In this study, we examined the effect of RANTES on eosinophil adhesion to plasma coated glass using eosinophilic cell line named EoL-1. RANTES augmented EoL-1 adherence to Plasma coated glass and EoL-1 adherence to plasma coated glass was inhibited by anti-VLA-4 antibody, anti-CR3 antibody. On the other hand, RANTES did not augment expression of adhesion molecules (VLA-4, CR3) on EoL-1. These findings indicate that RANTES intensify the adhesion of eosinophils without augmentation of their expression, and suggest that it induce qualitative, but not quantitative changes in their adherence. Taken together, our study suggest that RANTES up-regulates the inflammatory reaction through augmentative effect on adhesion of eosinophils in bronchial asthma.

Eosinophils were isolated by the three methods of CD16-negative depletion: 1) magnetic beads, 2) fluorescence-activated cell sorter (FACS), and 3) complement reaction. Their purity, yield, and viability were compared. The second procedure produced well purity and viability (94.65 +/- 1.51% and 94.98 +/- 1.40%, respectively) but low yield of eosinophils (65.47 +/- 2.47%). The viability of cells obtained by the third procedure was not efficient (80.83 +/- 2.85%), while the purity and the yield were efficient (96.23 +/- 1.09% and 90.75 +/- 1.72%, respectively). In conclusion, the magnetic beads method (purity: 98.02 +/- 0.45%, yield: 91.05 +/- 2.43%, viability: 97.57 +/- 0.37%) was the most advantageous of these three procedures. Moreover, in the functional assay, radical oxygen products from eosinophils isolated by the procedure with complement reaction were less than with the magnetic beads or FACS procedures.

RANTES, a member of the 8-kDa cytokine family, has been shown to possess chemotactic activity for eosinophils. In this study, RANTES augmented isolated human eosinophil adhesion to plates coated with recombinant soluble intercellular adhesion molecule 1. In addition, RANTES did not augment the expression of beta 2-integrin adhesion molecules (lymphocyte function associated antigen-1 alpha (LFA-1 alpha), LFA-1 beta, complement receptor type 3 (CR3)) on human eosinophils. These findings suggest that RANTES not only modulates the chemotactic activity of eosinophils but also intensifies the function of eosinophil adhesion without augmenting the expression of beta 2-integrin adhesion molecules.

Adhesion molecules may play an important role not only in adherence of inflammatory cells (particularly eosinophils) to an inflamed focus but also in activation of these cells. It is therefore of interest to evaluate eosinophil activation via intercellular adhesion molecule-1 (ICAM-1) and the beta 2-integrin family, namely CR3 (Mac-1), lymphocyte function-associated antigen (LFA)-1 alpha and LFA-1 beta, which are ligands for ICAM-1. Reactive oxygen species generated by eosinophils have also been considered capable of causing airway injury at the inflamed focus. This study examined the effect of recombinant soluble ICAM-1 and its ligands on eosinophil-induced radical oxygen products in terms of luminol-dependent chemiluminescence. Recombinant soluble ICAM-1 augmented eosinophil oxidative metabolism. It was concluded that signaling via adhesion molecules might play an important role in the pathogenesis of allergic inflammation through activation of eosinophils, e.g. an increase in oxidative metabolism.

The presence of a large variety of membrane receptors and the identification of cytotoxic molecules (mainly granule basic proteins) have indicated that eosinophils should br considered as effector cells. It has recently been suggested that adhesion molecules, particularly intercellular adhesion molecule-1 (ICAM-1), play an important role in allergic inflammation, for example in bronchial asthma. This study therefore investigated the possible release of granule protein in response to signaling from ICAM-1 and its ligands. The concentrations of eosinophil cationic protein and eosinophil-derived neurotoxin in supernatants of eosinophils were significantly greater (p < 0.05) in the presence of recombinant soluble ICAM-1 than without it. These results suggest that signaling from ICAM-1 and its ligands might induce eosinophil activation and might be involved in degranulation of eosinophil granule proteins, e.g. eosinophil cationic protein and eosinophil-derived neurotoxin.

RANTES, which is released from thrombin-stimulated platelets, is a member of the 8-kDa cytokine family that has been shown to possess chemotactic activity for eosinophils. The effect of RANTES on the intracellular expression of EG2 antigen in eosinophils was examined in this study. RANTES augmented the intracellular expression of EG2 antigen in eosinophils. These findings suggest that RANTES not only modulates the chemotactic activity of eosinophils but also intensifies the function of eosinophil activation.

Fibronectin, an extracellular matrix component, is a ligand for very late activation antigen (VLA)-4, which is one of the beta 1-integrin family of molecules expressed by eosinophils. This study examined the effect of adherence to fibronectin on radical oxygen products from eosinophils. Adhesion of eosinophils to fibronectin resulted in enhancement of eosinophil production of radical oxygen species, as determined by luminol-dependent chemiluminescence of eosinophils stimulated with calcium ionophore. It was concluded that eosinophil adhesion to extracellular matrix via adhesion molecules may be important in the pathogenesis of allergic inflammation through eosinophil activation.

Adhesion molecules recently have been considered to play an important role in inflammatory processes in bronchial asthma. Our previous study revealed high expression of beta 2-integrin family (CR3, LFA-1 alpha, CD18) on hypodense eosinophils. Thus, from the point of view of cell-to-cell interaction between mononuclear cells and eosinophils, we examined whether the supernatant of mononuclear cells obtained from mite-allergic asthmatic patients cultured with specific allergen mite-allergen is involved in adhesion molecule expression using an eosinophilic cell line (EoL-1). These characteristics of beta 2-integrin family expression (high expression of beta 2 integrin) were induced by the supernatant of mononuclear cells from mite-allergic asthmatic patients stimulated with mite-allergen as well as with a combination of the recombinant eosinophilopoietic growth cytokines (IL-3, GM-CSF and IL-5). Thus, we could conclude that some cytokines produced by specific allergen stimulated mononuclear cells in asthmatics might be involved in allergic inflammation through the induction of adhesion molecule expression on eosinophils in asthma or allergic disorders.

Adhesion molecules on various inflammatory cells, especially on eosinophils are now considered to play an important role in allergic inflammations such as bronchial asthma. In this study, we examined the effect of platelet-activating factor (PAF) on eosinophil adhesion to plasma-coated glass using eosinophilic cell lines (EoL-1, EoL-3), since PAF might be an important mediator as an eosinophil chemotactic agent in bronchial asthma. PAF markedly augmented adherence to plasma-coated plates. This finding suggests that PAF might up-regulate the inflammatory reaction in bronchial asthma through its action as an augmentative agent for eosinophil adhesion as well as its action as an eosinophil chemotactic agent.

Recently, adhesion molecules have been considered to play an important role in inflammatory processes in bronchial asthma. To extend our understanding of the high-intensity expression of adhesion molecules (CR3, LFA-1 alpha, LFA-1 beta, ICAM-1) on hypodense eosinophils, which was observed in our previous study, we examined whether the supernatant of lymphocytes from mite-allergic asthmatic patients is involved in adhesion molecule expression using an eosinophilic cell line (EoL-1). These characteristics of adhesion molecule expression were induced by the supernatant of lymphocytes obtained from mite-allergic asthmatic patients cultured with specific allergen as well as a combination of recombinant cytokines (IL-3, GM-CSF, IL-5). Thus, we could conclude that some lymphokines produced by specific allergen in asthma might be involved in the high-intensity expression of adhesion molecules on hypodense eosinophils in asthma or allergic disorders.

RANTES, which is released from thrombin-stimulated platelets, is a member of the 8-kD cytokine family that has been shown to possess chemotactic activity for eosinophils. Thus, in this study, we examined the effect of RANTES on radical oxygen products from eosinophils. RANTES treatment resulted in the enhancement of peak value and integrated value of productivity of eosinophil-mediated radical oxygen products determined by luminol-dependent chemiluminescence of EoL-3 cells stimulated with A23187. In addition, the radical oxygen products of EoL-1 or eosinophils showed similar results. Thus, we could conclude that platelets might play an important role in the pathogenesis of allergic inflammation through the involvement in the selective eosinophil infiltration and eosinophil activation by releasing RANTES.

The effect of platelet-activating factor (PAF) and platelet factor 4 (PF4) on the adhesion of isolated human eosinophils or eosinophilic cell lines (EoL-1, EoL-3) was examined. Both PAF and PF4 augmented eosinophil adhesion to plates coated with AB plasma or recombinant soluble intercellular adhesion molecule-1 (r-sICAM-1). These findings suggest that PAF and PF4 not only modulate chemotactic activity of eosinophils but also intensify the function of eosinophil adhesion. Since PAF and PF4 induce the expression of adhesion molecules (LFA-1 alpha, LFA-1 beta, CR3) on eosinophils, we could conclude that PAF or PF4 are closely related to eosinophil accumulation not only as chemotactic agents but also as augmentative agents for eosinophil adhesion through involvement in functional eosinophil adherence as well as surface expression of adhesion molecules on eosinophils.

Several characteristics of human eosinophil heterogeneity, as well as the existence of eosinophil subpopulations, "normodense" and "hypodense", have been reported in diseases associated with hypereosinophilia. Hypodense eosinophils can be distinguished by the increased expression of various membrane receptors including IL-5 receptor (J Exp Med 172: 1347) and various protein expression (J Immunol 142: 4416). On the other hand, recently, adhesion molecules are considered to play an important role in inflammatory processes in allergic and immune reactions such as bronchial asthma. Thus, in thin study, we examined the characteristics of expression of adhesion molecules on human eosinophils obtained from patients with hypereosinophila (hypodense eosinophils). As a result, high intensity expression of adhesion molecules (CR3, LFA-1 alpha, LFA-beta) on eosinophils were observed. Furthermore, ICAM-1, which is the ligand for LFA-1 molecules, was also expressed on eosinophils with hypereosinophilia. To extend our understanding of high intensity expression of adhesion molecules (CR3, LFA-1 alpha, LFA-1 beta, ICAM-1) on hypodense eosinophils, we examined whether chemotactic agents or eosinophilopoietic growth lymphokines (IL-3, GM-CSF, IL-5) are involved in adhesion molecule expression using an eosinophilic cell line, EoL-3. The expression of adhesion molecules on eosinophils was induced by some chemotactic agents and eosinophilopoietic growth lymphokines. Taken together, we conclude that eosinophilopoietic lymphokines as well as chemotactic agents may be involved in the high intensity expression of adhesion molecules on hypodense eosinophils.(ABSTRACT TRUNCATED AT 250 WORDS)

The functions of eosinophils in immunological reactions and their heterogeneity have recently generated a matter of great interest. Several characteristics of human eosinophil heterogeneity, as well as the existence of eosinophil subpopulations, called "normodense" and "hypodense", in diseases associated with hypereosinophilia, have been reported. Hypodense eosinophils can be distinguished by the increased expression of various membrane receptors including IL-5 receptor (J Exp Med 172: 1347) and various protein expression (J Immunol 142:4416). On the other hand, recently, adhesion molecules are considered to play an important role in inflammatory processes in allergic and immune reactions such as bronchial asthma. It was recently described that symptoms of bronchial asthma in animal model were in particular improved by means of anti-ICAM-1 (Intercellular adhesion molecule-1) monoclonal antibody (mAb). Thus, in thin study, we examined the characteristics of expression of adhesion molecules on human eosinophils obtained from hypereosinophilia (hypodense eosinophils). As results, high intensity expression of adhesion molecules (CR3, LFA-1 alpha, LFA-1 beta) on eosinophils obtained from patients with hypereosinophilia were observed. Furthermore, ICAM-1, which is ligand for LFA-1 molecules, was also expressed on eosinophils with hypereosinophilia. To extend our understanding of high intensity expression of adhesion molecules (CR3, LFA-1 alpha, LFA-1 beta, ICAM-1) on hypodense eosinophils, we examined whether chemotactic agents or eosinophilopoietic growth lymphokines (IL-3, GM-CSF, IL-5) is involved in adhesion molecule expression using an eosinophilic cell line named EoL-3. These characteristics of adhesion molecules on eosinophils were induced by some chemotactic agents and eosinophilopoietic growth lymphokines.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of IL-3, GM-CSF and IL-5 on the expression of CD23 (Fc(E)RII), CD25 (IL-2R/p55) and CD4 on an eosinophilic cell line (EoL-3) were investigated by flow cytometry. A separate incubation with IL-3, GM-CSF or IL-5, did not induce the expression of CD23, CD25, or CD4. However, a sequential incubation with IL-3, then with IL-3 and GM-CSF, induced a significant expression of CD23 and CD25. After a further incubation with IL-3, GM-CSF and IL-5, CD4 was then expressed, while CD23 and CD25 expression still increased. The kinetics of expression of CD11b were parallel to that of CD23, but the expression of the transferrin receptor (CD71) remained negative. Northern blot analysis revealed the presence of mRNA encoding CD23, CD25 and CD4 in EoL-3 stimulated by IL-3, GM-CSF and IL-5. Culture with GM-CSF induced the binding of radiolabeled IL-5 to EoL-3 cells, with an increased affinity after a sequential incubation with IL-3, GM-CSF and IL-5. These data indicate that IL-3, GM-CSF and IL-5, might be involved in the expression of functional markers on eosinophil membrane.

Interleukin-5 (IL-5) acts on eosinophil differentiation and activation, suggesting the existence of a membrane receptor for IL-5 on eosinophils. Here, we report that 125I-labeled recombinant human IL-5 bound to high affinity receptors on human eosinophils, especially pulmonary eosinophils in eosinophilic pneumonia obtained bronchoalveolar lavage (BAL). No specific binding occurred on neutrophils, nor on the undifferentiated eosinophilic cell line. EoL-3, in the absence of stimulation. The specific binding of IL-5 was induced by incubation at 37 degrees C of human eosinophils and EoL-3 cells with GM-CSF and with the supernatants of BAL cells from patients with eosinophilic pneumonia. These results indicate the existence of a specific binding site for IL-5 on human eosinophils with variable affinity in eosinophil hypodense or normodense subpopulations, as previously reported for other membrane receptors. Furthermore, lung cells (BAL cells) in patients with eosinophilic pneumonia may be involved in the production certain eosinophilopoietic growth cytokines such as IL-3, GM-CSF and IL-5.

Recently, much attention has been paid to the role played by the allergic inflammatory reaction in the role of asthma. Eosinophils are considered to be major inflammatory cells in bronchial asthma. Therefore, in this study, eosinophil-mediated oxygen radicals were examined by means of luminol-dependent chemiluminescence. Also, the effect of oxatomide, an anti-allergic agent, which has an inhibitory effect on eosinophil-mediated natural cytotoxicity against bronchial epithelial cells, on the production of oxygen radicals from eosinophils was studied. The results revealed the inhibitory effects of oxatomide on eosinophil-mediated oxygen radicals products. Furthermore, the inhibitory effect of this agent on oxygen radical products from eosinophilic cell-line named EoL-3, which has been established recently, was observed. We concluded from these results that oxatomide not only has anti-allergic activity but also anti-inflammatory properties for eosinophils.

Recently, eosinophils have been implicated as inflammatory effector cells in allergic and inflammatory reactions such as bronchial asthma. In this study eosinophil-mediated and eosinophilic cell line-mediated natural cytotoxicity against bronchial epithelial cells and the effects of oxatomide, an anti-allergic agent, on their cytotoxicity were investigated. Treatment with oxatomide diminished both eosinophil-mediated and eosinophilic cell line-mediated natural cytotoxicity in vitro. We concluded from these results that oxatomide not only has anti-allergic activity but also anti-inflammatory properties for eosinophils. In addition this method for isolating eosinophils seems to well serve the purpose of evaluating eosinophil function as in this investigation, as we have reported previously.

We have previously reported pulmonary eosinophils in eosinophilic pneumonia (PIE syndrome) showed two characteristics: hypodensity and nuclear hypersegmentation. Our present working hypothesis is that the eosinophil chemotactic factor and certain lymphokines may be involved in the induction of these characteristic features. Therefore, we examined whether these stimuli can induce two characteristics in vitro. Results were as follows. 1) Chemoattracts (ECF-A, histamine and PAF) can induce both nuclear hypersegmentation and hypodense eosinophils. 2) Hypodense eosinophils can be induced earlier than induction of hypersegmented nuclei (hypodense eosinophils within three hours, hypersegmented nuclei: 12 hrs). 3) Furthermore, lymphokines can not induce hypodense eosinophil. 4) However, PHA-lymphocyte culture medium (PHALCM), gamma-IFN and IL-3 + GM-CSF can induce hypersegmented nuclei but IL-2 has no effect on nuclear segmentation of eosinophils.