Disparate effects of interleukin 11 and thrombopoietin on megakaryocytopoiesis in vitro

The effects of interleukin-11 (IL-11) and thrombopoietin (TPO) on murine megakaryocytopoiesis were studied using a serum-free culture system. Acting alone, both IL-11 and TPO increased the number of acetylcholinesterase (AchE)(+)cells (megakaryocytes), the latter being more potent than the former. TPO, but not IL-11, increased the mean AchE activity per megakaryocyte (AchE activity/megakaryocyte). TPO increased both the number of megakaryocytes with high ploidy, and of those with low ploidy. In contrast, IL-11 increased only the number of megakaryocytes with high ploidy. The effect of TPO on megakaryocyte ploidy was stronger than that of IL-11. Both IL-11 and TPO increased the proportion of large megakaryocytes, but the latter was more potent than the former. While the stimulatory effects of IL-11 and TPO on the number of megakaryocytes were enhanced by IL-3 or stem cell factor (SCF), synergism of IL-11 or TPO with IL-3 or SCF in stimulating AchE activity/megakaryocyte was inconsistent. IL-11 and TPO stimulated the formation of colony-forming units of megakaryocyte in the presence of IL-3, but not alone, with similar maximum colony numbers for both cytokines. Our findings thus demonstrate that IL-11 principally stimulates megakaryocyte maturation rather than the proliferation of megakaryocytes, whereas TPO stimulates both.     

Different chemokines are expressed in human arthritic bone biopsies: IFN-gamma and IL-6 differently modulate IL-8, MCP-1 and rantes production by arthritic osteoblasts

In the present study we analyse chemokine expression in the remodelling of subchondral bone in arthritis patients. Trabecular bone biopsies were tested by immunohistochemistry to identify interleukin (IL)-8, GRO-alpha, MCP-1, RANTES, MIP-1alpha and MIP-1beta expression. Subsequently, we evaluated by immunoassay the effect of interferon (IFN)-gamma and IL-6 on chemokine production by osteoarthritis (OA), rheumatoid arthritis (RA) and post-traumatic (PT) patients' isolated osteoblasts (OB). OB constitutively produced in situ IL-8, GRO-alpha, MCP-1, RANTES and MIP-1alpha. MIP-1beta was positive only in mononuclear cells. In RA many of these chemokines were also produced by mononuclear cells. IFN-gamma significantly down-regulated IL-8 and up-regulated MCP-1 produced by OB from all patients tested, whereas it did not affect the other chemokines analysed. Moreover, IFN-gamma reduced IL-1beta-stimulated IL-8 production but significantly increased both MCP-1 and RANTES. Interestingly, IL-6 significantly downregulated IFN-gamma-induced MCP-1 production, that was significantly lower in OA compared to RA patients. OB expressed chemokines both in vivo and in vitro suggesting that these cells are primary effectors in the bone capable of regulating autocrine/paracrine circuits that affect bone remodelling in these diseases.     

Modulatory roles of RANTES in IL-4 production by human blood CD4(+)T cells

An increase in serum IgE levels has been reported in several thrombotic cardiovascular diseases. Since such diseases are associated with the activation of platelets, we hypothesized that platelets are implicated in a mechanism leading to heightened IgE synthesis. To this end, we performed an in vitro investigation of the effects on IL-4 production caused by several bioactive substances potentially released from platelets. Human blood CD4(+)T cells from blood donors were stimulated with anti-CD3 antibody and costimulatory signals delivered via CD58 and CD80 in the presence or absence of IL-4. One of the following test substances was also included in the culture: platelet factor-4, beta-thromboglobulin, platelet-derived growth factor, serotonin, platelet activating factor, or RANTES. The cells were restimulated in the absence of IL-4 and test substances. Among the six substances, RANTES alone exhibited significant effects on IL-4 production. RANTES enhanced IL-4 production in the presence of IL-4, whereas it suppressed IL-4 production in the absence of IL-4. The enhancing effect of RANTES was positively correlated with plasma IgE levels in the donors. We concluded that RANTES may induce IgE synthesis by increasing IL-4 production in individuals predisposed to high IgE responses. Our observations indicate a link between platelets and immune phenomena associated with increased IgE responses.     

Differential regulation of epithelial-derived C-C chemokine expression by IL-4 and the glucocorticoid budesonide.

Airway epithelial cells are a rich source of eosinophil-selective C-C chemokines. We investigated whether cytokines and the topical glucocorticoid budesonide differentially regulate RANTES, monocyte chemoattractant protein-4 (MCP-4), and eotaxin mRNA and protein expression in the human bronchial epithelial cell line BEAS-2B and in primary human bronchial epithelial cells by Northern blot analysis and ELISAs. Eotaxin and MCP-4 mRNA expression induced by TNF-alpha alone or in combination with IFN-gamma was near-maximal after 1 h, peaked at 4 and 8 h, respectively, remained unchanged up to 24 h, and was protein synthesis independent. In contrast, RANTES mRNA was detectable only after 2 h and slowly increased to a peak at 24 h, and was protein synthesis dependent. Induction of eotaxin and MCP-4 mRNA showed a 10- to 100-fold greater sensitivity to TNF-alpha compared with RANTES mRNA. IL-4 and IFN-gamma had selective effects on chemokine expression; IL-4 selectively up-regulated the expression of eotaxin and MCP-4 and potentiated TNF-alpha-induced eotaxin, while IFN-gamma markedly potentiated only the TNF-alpha-induced expression of RANTES. Although budesonide inhibited the expression of chemokine mRNA to a variable extent, it effectively inhibited production of eotaxin and RANTES protein. Budesonide inhibited both RANTES- and eotaxin promoter-driven reporter gene activity. Budesonide also selectively accelerated the decay of eotaxin and MCP-4 mRNA. These results point to IL-4 as a possible mediator by which Th2 cells may induce selective production of C-C chemokines from epithelium and indicate that glucocorticoid inhibit chemokine expression through multiple mechanisms of action.     

Multiple levels of regulation of megakaryocytopoiesis

A working hypothesis for the regulation of megakaryocytopoiesis is described on the basis of current data. The hypothesis proposes that in vivo megakaryocytes are generated by 1) the expansion of clonable progenitor cells into immature megakaryocytes by locally produced (and regulated) interleukin-3 (IL-3) and 2) the development and maturation of immature megakaryocytes by a dual system; by a lineage specific mechanism involving thrombopoietic stimuli in the steady state and thrombocytopenic conditions, and by a lineage nonspecific mechanism via IL-3 in damaged or reconstituting marrow. The hypothesis predicts that if IL-3 is a significant in vivo regulator of megakaryocyte formation and development, receptor for IL-3 should be present on megakaryocytes and may be vestigially on platelets. Small but significant levels of 125I IL-3 were found to bind to platelets from normal mice. The level of binding on platelets was found to be enhanced sevenfold from mice that had received high levels of irradiation followed by bone marrow transplantation. This contrasted with a twofold increase in the level of binding to platelets from mice made acutely thrombocytopenic with antiplatelet serum. The data suggest that IL-3 may be involved in the in vivo regulation of murine megakaryocytopoiesis and may be a significant factor in rebound thrombopoiesis following bone marrow damage.     

Corticosteroid inhibition of growth-related oncogene protein-alpha via mitogen-activated kinase phosphatase-1 in airway smooth muscle cells

Expression of the inflammatory chemokine, growth-related oncogene protein-alpha (GRO-alpha), from airway smooth muscle cells (ASMC) is regulated by pathways involving NF-kappaB and MAPK activation. We determined the effects of dexamethasone on GRO-alpha induced by IL-1beta or TNF-alpha with respect to the role of MAPK pathways and of MAPK phosphatase-1 (MKP-1). Human ASMC were studied in primary culture at confluence. Dexamethasone (10(-8)-10(-5) M) partially inhibited GRO-alpha expression and release induced by IL-1beta and TNF-alpha; this was associated with an inhibition of JNK, but not of p38 or ERK phosphorylation. Together with IL-1beta or TNF-alpha, dexamethasone rapidly induced mRNA and protein expression of MKP-1, which dephosphorylates MAPKs. Using MKP-1 small interfering RNA (siRNA) to block the expression of IL-1beta- and dexamethasone-induced MKP-1 by 50%, JNK phosphorylation was doubled. The inhibitory effect of dexamethasone on GRO-alpha release was partially reversed in ASMC treated with MKP-1 siRNA compared with those treated with scrambled siRNA. In contrast, overexpression of MKP-1 led to a reduction in IL-1beta-induced release of GRO-alpha, but the inhibitory effects of dexamethasone were preserved. Nuclear translocation of the glucocorticoid receptor was increased in ASMC exposed to dexamethasone and IL-1beta. Using chromatin immunoprecipitation assay, glucocorticoid receptor binding to the MKP-1 promoter was increased by IL-1beta and dexamethasone compared with either alone. Glucocorticoids and IL-1beta or TNF-alpha modulate GRO-alpha release partly through the inhibition of JNK pathway, resulting from an up-regulation of MKP-1 expression.     

Expression of CXC and CC type of chemokines and its receptors in tuberculous and non-tuberculous effusions

Chemokines mediate their biological functions by transmigration of various immune cells to the site of infection. Tuberculous pleurisy provides an effective model to study the role of chemokines in the recruitment of immune cells to the pleura. Our aim was to understand the cumulative effect of chemokines (IP-10, MIG, IL-8, MCP-1, MIP-1α and RANTES) and its receptors (CXCR2, CXCR3, CCR1, CCR2, CCR5 and CCR7) in the recruitment of CD4⁺ T cells obtained from blood (BL) and pleural fluid (PF) of tuberculous (TB) and non-tuberculous (NTB) patients. We observed significant increase in CD4⁺ T cells in TB PF indicating lymphocytic rich effusion. All chemokines except RANTES were significantly high in PF compared to BL in TB group, whereas IL-8 and MCP-1 showed significant increase only in NTB PF. The significantly high levels of IFN-γ and ΤΝF-α in TB PF and their positive correlation with IP-10 and MIP-1α indicated their synergistic action to elicit a strong protective Th1 response. In spite of high levels of Th1 cytokines and chemokines in TB PF, significantly lower levels of RANTES indicated its limited role at the site. The CXC receptors in PF of both the groups and CC receptors except CCR5 in TB PF were significantly high compared to BL. Only CXCR2, CCR5 and CCR7 showed significant increase in TB compared to NTB. Thus a selective concentration of chemokines, cytokines and abundant expression of chemokine receptors confirm the accumulation of activated and memory T cells at the site of infection and help in polarizing Th1 immune response.     

Duffy antigen facilitates movement of chemokine across the endothelium in vitro and promotes neutrophil transmigration in vitro and in vivo

The Duffy Ag expressed on RBCs, capillaries, and postcapillary venular endothelial cells binds selective CXC and CC chemokines with high affinity. Cells transfected with the Duffy Ag internalize but do not degrade chemokine ligand. It has been proposed that Duffy Ag transports chemokines across the endothelium. We hypothesized that Duffy Ag participates in the movement of chemokines across the endothelium and, by doing so, modifies neutrophil transmigration. We found that the Duffy Ag transfected into human endothelial cells facilitates movement of the radiolabeled CXC chemokine, growth related oncogene-alpha/CXC chemokine ligand 1 (GRO-alpha/CXCL1), across an endothelial monolayer. In addition, neutrophil migration toward GRO-alpha/CXCL1 and IL-8 (IL-8/CXCL8) was enhanced across an endothelial monolayer expressing the Duffy Ag. Furthermore, GRO-alpha/CXCL1 stimulation of endothelial cells expressing the Duffy Ag did not affect gene expression by oligonucleotide microarray analysis. These in vitro observations are supported by the finding that IL-8/CXCL8-driven neutrophil recruitment into the lungs was markedly attenuated in transgenic mice lacking the Duffy Ag. We conclude that Duffy Ag has a role in enhancing leukocyte recruitment to sites of inflammation by facilitating movement of chemokines across the endothelium.     

Interleukin-8 and growth-regulated oncogene alpha mediate angiogenesis in Kaposi's sarcoma

The development of the complex neoplasm Kaposi's sarcoma is dependent on infection with the Kaposi's sarcoma-associated herpesvirus (KSHV) and appears to be greatly enhanced by cytokines and human immunodeficiency virus type 1 (HIV-1) Tat. Interleukin-8 (IL-8) and growth-regulated oncogene alpha (GRO-alpha) are chemokines involved in chemoattraction, neovascularization, and stimulation of HIV-1 replication. We have previously demonstrated that production of GRO-alpha is stimulated by exposure of monocyte-derived macrophages (MDM) to HIV-1. Here we show that exposure of MDM to HIV-1, viral Tat, or viral gp120 leads to a substantial increase in IL-8 production. We also demonstrate that IL-8 and GRO-alpha are induced by KSHV infection of endothelial cells and are crucial to the angiogenic phenotype developed by KSHV-infected endothelial cells in cell culture and upon implantation into SCID mice. Thus, the three known etiological factors in Kaposi's sarcoma pathogenesis-KSHV, HIV-1 Tat, and cellular growth factors-might be linked, in part, through induction of IL-8 and GRO-alpha.     

Interleukin-8 stimulates human immunodeficiency virus type 1 replication and is a potential new target for antiretroviral therapy

Production of the C-X-C chemokines interleukin-8 (IL-8) and growth-regulated oncogene alpha (GRO-alpha) in macrophages is stimulated by exposure to human immunodeficiency virus type 1 (HIV-1). We have demonstrated previously that GRO-alpha then stimulates HIV-1 replication in both T lymphocytes and macrophages. Here we demonstrate that IL-8 also stimulates HIV-1 replication in macrophages and T lymphocytes. We further show that increased levels of IL-8 are present in the lymphoid tissue of patients with AIDS. In addition, we demonstrate that compounds which inhibit the actions of IL-8 and GRO-alpha via their receptors, CXCR1 and CXCR2, also inhibit HIV-1 replication in both T lymphocytes and macrophages, indicating potential therapeutic uses for these compounds in HIV-1 infection and AIDS.     

IL-1α induces thrombopoiesis through megakaryocyte rupture in response to acute platelet needs

Intravital visualization of thrombopoiesis revealed that formation of proplatelets, which are cytoplasmic protrusions in bone marrow megakaryocytes (MKs), is dominant in the steady state. However, it was unclear whether this is the only path to platelet biogenesis. We have identified an alternative MK rupture, which entails rapid cytoplasmic fragmentation and release of much larger numbers of platelets, primarily into blood vessels, which is morphologically and temporally different than typical FasL-induced apoptosis. Serum levels of the inflammatory cytokine IL-1α were acutely elevated after platelet loss or administration of an inflammatory stimulus to mice, whereas the MK-regulator thrombopoietin (TPO) was not elevated. Moreover, IL-1α administration rapidly induced MK rupture–dependent thrombopoiesis and increased platelet counts. IL-1α–IL-1R1 signaling activated caspase-3, which reduced plasma membrane stability and appeared to inhibit regulated tubulin expression and proplatelet formation, and ultimately led to MK rupture. Collectively, it appears the balance between TPO and IL-1α determines the MK cellular programming for thrombopoiesis in response to acute and chronic platelet needs.     

Large generation of megakaryocytes from serum-free expanded human CD34 cells

Ex vivo generation of megakaryocytes from hematopoietic stem cells (HSCs) is crucial to HSC research and has important clinical potential for thrombocytopenia patients to rapid platelet reconstruction. In this study, factorial design and steepest ascent method were used to screen and optimize the effective cytokines (10.2 ng/ml TPO, 4.3 ng/ml IL-3, 15.0 ng/ml SCF, 5.6 ng/ml IL-6, 2.8 ng/ml FL, 2.8 ng/ml IL-9, and 2.8 ng/ml GM-CSF) in megakaryocyte induction medium that facilitate ex vivo megakaryopoiesis from CD34⁺ cells. After induction, the maximum fold expansion for accumulated megakaryocytes was almost 5000-fold, and the induced megakaryocytes were characterized by analysis of gene expression, polyploidy and platelet activation ability. Furthermore, the combination of megakaryocyte induction medium and HSC expansion medium can induce and expand a large amount of functional megakaryocytes efficiently, and might be a promising source of megakaryocytes and platelets for cell therapy in the future.     

Platelet sparing effect of COX II inhibition used with pegylated interferon alfa-2a for the treatment of chronic hepatitis C: a short term pilot study

The role of a cyclooxygenase (COX) II inhibitor in reducing microvascular inflammation and the platelet count associated with interferon (IFN) plus ribavirin therapy of chronic hepatitis C (HCV) was assessed. Three plasma mediators (biomarkers) associated with platelet activation, inflammation and fibrosis were measured. Eighteen IFN na?ve patients were studied. Nine were treated with pegylated IFN alfa-2a (PEG-IFN alpha-2a) plus ribavirin and rofecoxib; nine were treated with PEG-IFN alpha-2a plus ribavirin. A complete blood count, liver panel and HCV-RNA were assayed weekly. Human soluble P-selectin (hs-P-selectin), human interleukin-8 (IL-8), human interleukin-13 (IL-13) and human thrombopoietin (TPO) were assayed at 4 week intervals. The COX II inhibitor reduced the platelet reduction experienced with PEG-IFN alpha-2a treatment of HCV despite a reduction in the plasma TPO level. Hs-P-selectin was increased in both groups. In contrast, human IL-8 levels declined to undetectable levels in virologic responders. Similarly, human IL-13 levels declined with therapy (P < 0.001). These data suggest that: (1) a COX II inhibition is associated with an increase in the platelet count despite a reduction in the TPO level; (2) human IL-8 and human IL-13 but not hs-P-selectin levels decline in those who experience an early virologic response.     

Lysophosphatidic acid enhances interleukin-13 gene expression and promoter activity in T cells

Airway smooth muscle cells (ASMC) are a source of inflammatory chemokines that may propagate airway inflammatory responses. We investigated the production of the CXC chemokine growth-related oncogene protein-alpha (GRO-alpha) from ASMC induced by cytokines and the role of MAPK and NF-kappaB pathways. ASMC were cultured from human airways, grown to confluence, and exposed to cytokines IL-1beta and TNF-alpha after growth arrest. GRO-alpha release, measured by ELISA, was increased by >50-fold after IL-1beta (0.1 ng/ml) or 5-fold after TNF-alpha (1 ng/ml) in a dose- and time-dependent manner. GRO-alpha release was not affected by the T helper type 2 cytokines IL-4, IL-10, and IL-13. IL-1beta and TNF-alpha also induced GRO-alpha mRNA expression. Supernatants from IL-1beta-stimulated ASMC were chemotactic for neutrophils; this effect was inhibited by anti-GRO-alpha blocking antibody. AS-602868, an inhibitor of IKK-2, and PD-98059, an inhibitor of ERK, inhibited GRO-alpha release and mRNA expression, whereas SP-600125, an inhibitor of JNK, reduced GRO-alpha release without effect on mRNA expression. SB-203580, an inhibitor of p38 MAPK, had no effect. AS-602868 but not PD-98059 or SP-600125 inhibited p65 DNA-binding induced by IL-1beta and TNF-alpha. By chromatin immunoprecipitation assay, IL-1beta and TNF-alpha enhanced p65 binding to the GRO-alpha promoter, which was inhibited by AS-602868. IL-1beta- and TNF-alpha-stimulated expression of GRO-alpha from ASMC is regulated by independent pathways involving NF-kappaB activation and ERK and JNK pathways. GRO-alpha released from ASMC participates in neutrophil chemotaxis.     

Isolation and characterization of mouse homolog of the neutrophil activating peptide-2.

In the presence of thrombopoietin (TPO), megakaryocytes mature by polyploidization and cytoplasmic maturation, and the matured megakaryocytes induce drastic morphological change and proplatelet formation and release a number of platelets. However, the regulatory mechanism of this unique differentiation process is still obscure. We therefore attempted to identify the factors, expression of which is induced by TPO stimulation in mouse bone marrow megakaryocytes. We isolated the mouse homolog of the neutrophil activating peptide-2 (NAP-2). Mouse NAP-2 cDNA encodes a predicted sequence of 113 amino acids and contains the Cys motif (CXC) found in other members of the alpha-chemokine family. At the amino acid level, the predicted mouse NAP-2 has 50.4%, 51.8%, and 72.6% identity with the predicted human, pig, and rat NAP-2, respectively. Northern blot analysis demonstrates that mouse NAP-2 is expressed only in spleen. Furthermore, the RT-PCR technique shows that the mouse NAP-2 gene is clearly upregulated by TPO stimulation in mouse megakaryocytes.     

Cigarette smoke induces IL-8, but inhibits eotaxin and RANTES release from airway smooth muscle

Background

Cigarette smoke is the leading risk factor for the development of chronic obstructive pulmonary disease (COPD) an inflammatory condition characterised by neutrophilic inflammation and release of proinflammatory mediators such as interleukin-8 (IL-8). Human airway smooth muscle cells (HASMC) are a source of proinflammatory cytokines and chemokines. We investigated whether cigarette smoke could directly induce the release of chemokines from HASMC.

Methods

HASMC in primary culture were exposed to cigarette smoke extract (CSE) with or without TNFα. Chemokines were measured by enzyme-linked immunosorbent assay (ELISA) and gene expression by real time polymerase chain reaction (PCR). Data were analysed using one-way analysis of variance (ANOVA) followed by Bonferroni''s t test

Results

CSE (5, 10 and 15%) induced IL-8 release and expression without effect on eotaxin or RANTES release. At 20%, there was less IL-8 release. TNFα enhanced CSE-induced IL-8 release and expression. However, CSE (5–30%) inhibited TNFα-induced eotaxin and RANTES production. The effects of CSE on IL-8 release were inhibited by glutathione (GSH) and associated with the induction of the oxidant sensing protein, heme oxygenase-1.

Conclusion

Cigarette smoke may directly cause the release of IL-8 from HASMC, an effect enhanced by TNF-α which is overexpressed in COPD. Inhibition of eotaxin and RANTES by cigarette smoke is consistent with the predominant neutrophilic but not eosinophilic inflammation found in COPD.     

Clopidogrel, a P2Y12 receptor antagonist, potentiates the inflammatory response in a rat model of peptidoglycan polysaccharide-induced arthritis

The P2Y12 receptor plays a crucial role in the regulation of platelet activation by several agonists, which is irreversibly antagonized by the active metabolite of clopidogrel, a widely used anti-thrombotic drug. In this study, we investigated whether reduction of platelet reactivity leads to reduced inflammatory responses using a rat model of erosive arthritis. We evaluated the effect of clopidogrel on inflammation in Lewis rats in a peptidoglycan polysaccharide (PG-PS)-induced arthritis model with four groups of rats: 1) untreated, 2) clopidogrel-treated, 3) PG-PS-induced, and 4) PG-PS-induced and clopidogrel-treated. There were significant differences between the PG-PS+clopidogrel group when compared to the PG-PS group including: increased joint diameter and clinical manifestations of inflammation, elevated plasma levels of pro-inflammatory cytokines (IL-1 beta, interferon (IFN) gamma, and IL-6), an elevated neutrophil blood count and an increased circulating platelet count. Plasma levels of IL-10 were significantly lower in the PG-PS+clopidogrel group compared to the PG-PS group. Plasma levels of platelet factor 4 (PF4) were elevated in both the PG-PS and the PG-PS+clopidogrel groups, however PF4 levels showed no difference upon clopidogrel treatment, suggesting that the pro- inflammatory effect of clopidogrel may be due to its action on cells other than platelets. Histology indicated an increase in leukocyte infiltration at the inflammatory area of the joint, increased pannus formation, blood vessel proliferation, subsynovial fibrosis and cartilage erosion upon treatment with clopidogrel in PG-PS-induced arthritis animals. In summary, animals treated with clopidogrel showed a pro-inflammatory effect in the PG-PS-induced arthritis animal model, which might not be mediated by platelets. Elucidation of the mechanism of clopidogrel-induced cell responses is important to understand the role of the P2Y12 receptor in inflammation.     

Effects of nano particles on antigen-related airway inflammation in mice

Background

Particulate matter (PM) can exacerbate allergic airway diseases. Although health effects of PM with a diameter of less than 100 nm have been focused, few studies have elucidated the correlation between the sizes of particles and aggravation of allergic diseases. We investigated the effects of nano particles with a diameter of 14 nm or 56 nm on antigen-related airway inflammation.

Methods

ICR mice were divided into six experimental groups. Vehicle, two sizes of carbon nano particles, ovalbumin (OVA), and OVA + nano particles were administered intratracheally. Cellular profile of bronchoalveolar lavage (BAL) fluid, lung histology, expression of cytokines, chemokines, and 8-hydroxy-2''-deoxyguanosine (8-OHdG), and immunoglobulin production were studied.

Results

Nano particles with a diameter of 14 nm or 56 nm aggravated antigen-related airway inflammation characterized by infiltration of eosinophils, neutrophils, and mononuclear cells, and by an increase in the number of goblet cells in the bronchial epithelium. Nano particles with antigen increased protein levels of interleukin (IL)-5, IL-6, and IL-13, eotaxin, macrophage chemoattractant protein (MCP)-1, and regulated on activation and normal T cells expressed and secreted (RANTES) in the lung as compared with antigen alone. The formation of 8-OHdG, a proper marker of oxidative stress, was moderately induced by nano particles or antigen alone, and was markedly enhanced by antigen plus nano particles as compared with nano particles or antigen alone. The aggravation was more prominent with 14 nm of nano particles than with 56 nm of particles in overall trend. Particles with a diameter of 14 nm exhibited adjuvant activity for total IgE and antigen-specific IgG₁ and IgE.

Conclusion

Nano particles can aggravate antigen-related airway inflammation and immunoglobulin production, which is more prominent with smaller particles. The enhancement may be mediated, at least partly, by the increased local expression of IL-5 and eotaxin, and also by the modulated expression of IL-13, RANTES, MCP-1, and IL-6.