IFN-gamma-inducible protein 10 (CXCL10) contributes to airway hyperreactivity and airway inflammation in a mouse model of asthma

Allergic asthma is an inflammatory disease of the airways characterized by eosinophilic inflammation and airway hyper-reactivity. Cytokines and chemokines specific for Th2-type inflammation predominate in asthma and in animal models of this disease. The role of Th1-type inflammatory mediators in asthma remains controversial. IFN-gamma-inducible protein 10 (IP-10; CXCL10) is an IFN-gamma-inducible chemokine that preferentially attracts activated Th1 lymphocytes. IP-10 is up-regulated in the airways of asthmatics, but its function in asthma is unclear. To investigate the role of IP-10 in allergic airway disease, we examined the expression of IP-10 in a murine model of asthma and the effects of overexpression and deletion of IP-10 in this model using IP-10-transgenic and IP-10-deficient mice. Our experiments demonstrate that IP-10 is up-regulated in the lung after allergen challenge. Mice that overexpress IP-10 in the lung exhibited significantly increased airway hyperreactivity, eosinophilia, IL-4 levels, and CD8(+) lymphocyte recruitment compared with wild-type controls. In addition, there was an increase in the percentage of IL-4-secreting T lymphocytes in the lungs of IP-10-transgenic mice. In contrast, mice deficient in IP-10 demonstrated the opposite results compared with wild-type controls, with a significant reduction in these measures of Th2-type allergic airway inflammation. Our results demonstrate that IP-10, a Th1-type chemokine, is up-regulated in allergic pulmonary inflammation and that this contributes to the airway hyperreactivity and Th2-type inflammation seen in this model of asthma.     

Gene expression and production of the monokine induced by IFN-gamma (MIG), IFN-inducible T cell alpha chemoattractant (I-TAC), and IFN-gamma-inducible protein-10 (IP-10) chemokines by human neutrophils

Monokine induced by IFN-gamma (MIG), IFN-inducible T cell alpha chemoattractant (I-TAC), and IFN-gamma-inducible protein of 10 kDa (IP-10) are related members of the CXC chemokine subfamily that bind to a common receptor, CXCR3, and that are produced by different cell types in response to IFN-gamma. We have recently reported that human polymorphonuclear neutrophils (PMN) have the capacity to release IP-10. Herein, we show that PMN also have the ability to produce MIG and to express I-TAC mRNA in response to IFN-gamma in combination with either TNF-alpha or LPS. While IFN-gamma, alone or in association with agonists such as fMLP, IL-8, granulocyte (G)-CSF and granulocyte-macrophage (GM)-CSF, failed to influence MIG, IP-10, and I-TAC gene expression, IFN-alpha, in combination with TNF-alpha, LPS, or IL-1beta, resulted in a considerable induction of IP-10 release by neutrophils. Furthermore, IL-10 and IL-4 significantly suppressed the expression of MIG, IP-10, and I-TAC mRNA and the extracellular production of MIG and IP-10 in neutrophils stimulated with IFN-gamma plus either LPS or TNF-alpha. Finally, supernatants harvested from stimulated PMN induced migration and rapid integrin-dependent adhesion of CXCR3-expressing lymphocytes; these activities were significantly reduced by neutralizing anti-MIG and anti-IP-10 Abs, suggesting that they were mediated by MIG and IP-10 present in the supernatants. Since MIG, IP-10, and I-TAC are potent chemoattractants for NK cells and Th1 lymphocytes, the ability of neutrophils to produce these chemokines might contribute not only to the progression and evolution of the inflammatory response, but also to the regulation of the immune response.     

Cytokine and chemokine mRNA expression in neutrophils from CBA/NSlc mice infected with Plasmodium berghei ANKA that induces experimental cerebral malaria.

To investigate the role of neutrophils in experimental cerebral malaria (ECM), in a previous study we found that early neutrophil depletion prevented the development of ECM and down regulated the expression of Th1 cytokines in the brain. To further clarify the mechanisms responsible for these findings, in the present study, using RT-PCR, we examined the expression of cytokine and chemokine mRNAs in neutrophils and macrophages after PbA infection. We found that, after infection, neutrophils not only expressed cytokines IL-2, IL-12p40, IL-18, IFN-gamma and TNF-alpha mRNAs, but also mRNAs for Th1 chemoattractive chemokines, monokine-induced by IFN-gamma (MIG), macrophage-inflammatory protein-1alpha (MIP-1alpha) and IFN-gamma inducible protein-10 (IP-10). Neutrophil depletion down regulated the expression of IL-18 and MIG mRNAs in macrophages, but did not affect the expression of IFN-gamma, TNF-alpha, MIP-1alpha and IP-10 mRNAs. Therefore, this study confirms our hypothesis that neutrophils may play a role in the pathogenesis of ECM via their expression of cytokines or chemokines.     

IL-4, but not IL-13, modulates TARC (thymus and activation-regulated chemokine)/CCL17 and IP-10 (interferon-induced protein of 10kDA)/CXCL10 release by TNF-alpha and IFN-gamma in HaCaT cell line

It is known that both interleukin-4 (IL-4) and IL-13 are produced by Th2-type cells and share similar biological functions with each other. However, recently accumulated evidences have revealed that IL-4 may be involved in the Th1-type response. Both thymus and activation-regulated chemokine (TARC/CCL17), a ligand for CC chemokine receptor 4 that is mainly expressed on Th2-type cells, and interferon-induced protein of 10kDa (IP-10/CXCL10), a ligand for CXC chemokine receptor 3 that is mainly expressed on Th1-type cells, are produced by keratinocytes after the stimulation with the primary cytokines such as tumor necrotic factor-alpha (TNF-alpha) and/or interferon-gamma (IFN-gamma). In this study, we investigated the regulation of TARC or IP-10 production from HaCaT cells, an immortalized human keratinocyte cell line, after stimulation with TNF-alpha, IFN-gamma, IL-4 and/or IL-13. Without stimulation, HaCaT cells did not produce TARC. When both TNF-alpha and IFN-gamma were added, they increased synergistically (P<0.003). In addition, when HaCaT cells were stimulated with IL-4, but not IL-13, in combination with TNF-alpha and IFN-gamma, the supernatant TARC levels significantly decreased compared to those with both TNF-alpha and IFN-gamma (P<0.009). This inhibition was completely abolished with the addition of neutralizing anti-IL-4 antibody. The supernatant IP-10 levels also increased synergistically by stimulation with TNF-alpha and IFN-gamma for 24h (P<0.001). When IL-4, but not IL-13, was added to the medium and the cells were co-cultured with these cytokines, the IP-10 levels significantly increased compared to those with both TNF-alpha and IFN-gamma (P<0.04). Furthermore, the effects of IL-4 on TARC and IP-10 production in these cells were detected in a dose-dependent manner. These data strongly suggest that IL-4 may act not only as a mediator of Th1-type response but also as a down-regulator of Th2-type response in terms of the regulation of chemokine production by HaCaT cells.     

Murine cytomegalovirus infection alters Th1/Th2 cytokine expression, decreases airway eosinophilia, and enhances mucus production in allergic airway disease

Concomitant infection of murine CMV (MCMV), an opportunistic respiratory pathogen, altered Th1/Th2 cytokine expression, decreased bronchoalveolar lavage (BAL) fluid eosinophilia, and increased mucus production in a murine model of OVA-induced allergic airway disease. Although no change in the total number of leukocytes infiltrating the lung was observed between challenged and MCMV/challenged mice, the cellular profile differed dramatically. After 10 days of OVA-aerosol challenge, eosinophils comprised 64% of the total leukocyte population in BAL fluid from challenged mice compared with 11% in MCMV/challenged mice. Lymphocytes increased from 11% in challenged mice to 30% in MCMV/challenged mice, and this increase corresponded with an increase in the ratio of CD8(+) to CD4(+)TCRalphabeta lymphocytes. The decline in BAL fluid eosinophilia was associated with a change in local Th1/Th2 cytokine profiles. Enhanced levels of IL-4, IL-5, IL-10, and IL-13 were detected in lung tissue from challenged mice by RNase protection assays. In contrast, MCMV/challenged mice transiently expressed elevated levels of IFN-gamma and IL-10 mRNAs, as well as decreased levels of IL-4, IL-5, and IL-13 mRNAs. Elevated levels of IFN-gamma and reduced levels of IL-5 were also demonstrated in BAL fluid from MCMV/challenged mice. Histological evaluation of lung sections revealed extensive mucus plugging and epithelial cell hypertrophy/hyperplasia only in MCMV/challenged mice. Interestingly, the development of airway hyperresponsiveness was observed in challenged mice, not MCMV/challenged mice. Thus, MCMV infection can modulate allergic airway inflammation, and these findings suggest that enhanced mucus production may occur independently of BAL fluid eosinophilia.     

Regulation of macrophage chemokine expression by lipopolysaccharide in vitro and in vivo.

The host response to Gram-negative LPS is characterized by an influx of inflammatory cells into host tissues, which is mediated, in part, by localized production of chemokines. The expression and function of chemokines in vivo appears to be highly selective, though the molecular mechanisms responsible are not well understood. All CXC (IFN-gamma-inducible protein (IP-10), macrophage inflammatory protein (MIP)-2, and KC) and CC (JE/monocyte chemoattractant protein (MCP)-1, MCP-5, MIP-1alpha, MIP-1beta, and RANTES) chemokine genes evaluated were sensitive to stimulation by LPS in vitro and in vivo. While IL-10 suppressed the expression of all LPS-induced chemokine genes evaluated in vitro, treatment with IFN-gamma selectively induced IP-10 and MCP-5 mRNAs, but inhibited LPS-induced MIP-2, KC, JE/MCP-1, MIP-1alpha, and MIP-1beta mRNA and/or protein. Like the response to IFN-gamma, LPS-mediated induction of IP-10 and MCP-5 was Stat1 dependent. Interestingly, only the IFN-gamma-mediated suppression of LPS-induced KC gene expression was IFN regulatory factor-2 dependent. Treatment of mice with LPS in vivo also induced high levels of chemokine mRNA in the liver and lung, with a concomitant increase in circulating protein. Hepatic expression of MIP-1alpha, MIP-1beta, RANTES, and MCP-5 mRNAs were dramatically reduced in Kupffer cell-depleted mice, while IP-10, KC, MIP-2, and MCP-1 were unaffected or enhanced. These findings indicate that selective regulation of chemokine expression in vivo may result from differential response of macrophages to pro- and antiinflammatory stimuli and to cell type-specific patterns of stimulus sensitivity. Moreover, the data suggest that individual chemokine genes are differentially regulated in response to LPS, suggesting unique roles during the sepsis cascade.     

The T cell-specific CXC chemokines IP-10, Mig, and I-TAC are expressed by activated human bronchial epithelial cells

Recruitment of activated T cells to mucosal surfaces, such as the airway epithelium, is important in host defense and for the development of inflammatory diseases at these sites. We therefore asked whether the CXC chemokines IFN-induced protein of 10 kDa (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha-chemoattractant (I-TAC), which specifically chemoattract activated T cells by signaling through the chemokine receptor CXCR3, were inducible in respiratory epithelial cells. The effects of proinflammatory cytokines, including IFN-gamma (Th1-type cytokine), Th2-type cytokines (IL-4, IL-10, and IL-13), and dexamethasone were studied in normal human bronchial epithelial cells (NHBEC) and in two human respiratory epithelial cell lines, A549 and BEAS-2B. We found that IFN-gamma, but not TNF-alpha or IL-1 beta, strongly induced IP-10, Mig, and I-TAC mRNA accumulation mainly in NHBEC and that TNF-alpha and IL-1 beta synergized with IFN-gamma induction in all three cell types. High levels of IP-10 protein (> 800 ng/ml) were detected in supernatants of IFN-gamma/TNF-alpha-stimulated NHBEC. Neither dexamethasone nor Th2 cytokines modulated IP-10, Mig, or I-TAC expression. Since IFN-gamma is up-regulated in tuberculosis (TB), using in situ hybridization we studied the expression of IP-10 in the airways of TB patients and found that IP-10 mRNA was expressed in the bronchial epithelium. In addition, IP-10-positive cells obtained by bronchoalveolar lavage were significantly increased in TB patients compared with normal controls. These results show that activated bronchial epithelium is an important source of IP-10, Mig, and I-TAC, which may, in pulmonary diseases such as TB (in which IFN-gamma is highly expressed) play an important role in the recruitment of activated T cells.     

Diesel exposure favors Th2 cell recruitment by mononuclear cells and alveolar macrophages from allergic patients by differentially regulating macrophage-derived chemokine and IFN-gamma-induced protein-10 production

Diesel exhausts and their associated organic compounds may be involved in the recent increase in the prevalence of allergic disorders, through their ability to favor a type 2 immune response. Type 2 T cells have been shown to be preferentially recruited by the chemokines eotaxin (CCL11), macrophage-derived chemokine (MDC, CCL22), and thymus activation-regulated chemokine (CCL17) through their interaction with CCR3 and CCR4, respectively, whereas type 1 T cells are mainly recruited by IFN-gamma-induced protein-10 (CXCL10) through CXCR3 binding. The aim of the study was to evaluate the effect of diesel exposure on the expression of chemokines involved in type 1 and 2 T cell recruitment. PBMC and alveolar macrophages from house dust mite allergic patients were incubated with combinations of diesel extracts and Der p 1 allergen, and chemokine production was analyzed. Diesel exposure alone decreased the constitutive IP-10 production, while it further augmented allergen-induced MDC production, resulting in a significantly increased capacity to chemoattract human Th2, but not Th1 clones. Inhibition experiments with anti-type 1 or type 2 cytokine Abs as well as cytokine mRNA kinetic evaluation showed that the chemokine variations were not dependent upon IL-4, IL-13, or IFN-gamma expression. In contrast, inhibition of the B7:CD28 pathway using a CTLA-4-Ig fusion protein completely inhibited diesel-dependent increase of allergen-induced MDC production. This inhibition was mainly dependent upon the CD86 pathway and to a lesser extent upon the CD80 pathway. These results suggest that the exposure to diesel exhausts and allergen may likely amplify a deleterious type 2 immune response via a differential regulation of chemokine production through the CD28 pathway.     

IFN-gamma-inducing factor (IL-18) increases allergic sensitization, serum IgE, Th2 cytokines, and airway eosinophilia in a mouse model of allergic asthma

We investigated the effects of IFN-gamma-inducing factor (IL-18) in a ragweed (RW) mouse model of allergic asthma. Administration of IL-18 in conjunction with allergic sensitization and challenge in wild-type, but not IFN-gamma -/- mice, inhibited the bronchoalveolar lavage (BAL) eosinophilia induced by RW challenge, and increased serum levels of RW-specific IgG2a and production of IFN-gamma from splenocytes cultured with RW, indicating a critical role for IFN-gamma in mediating these effects. Paradoxically, the same treatment schedule in WT mice increased serum levels of RW-specific IgE and IgG1, and production of IL-4 and IL-5 from splenocytes cultured with RW. When the effects of the same IL-18 treatment schedule were allowed to mature for 3 wk, the inhibition of lung eosinophil recruitment was replaced by augmentation of lung eosinophil recruitment. In another experiment, IL-18 administered only with allergic sensitization increased BAL eosinophilia and lung expression of IL-5 and IFN-gamma, while IL-18 administered only with RW challenge decreased BAL eosinophilia and increased lung IFN-gamma expression, while lung expression of IL-5 remained unchanged. IL-18 administered without RW or adjuvant to naive mice increased total serum IgE levels. Finally, intrapulmonary administrations of IL-18 plus RW in naive mice dramatically increased Th2 cytokine production, IgE levels, eosinophil recruitment, and airway mucus, demonstrating induction of allergic sensitization. This is the first report demonstrating that IL-18 promotes a Th2 phenotype in vivo, and potently induces allergic sensitization. These results suggest that IL-18 may contribute to the pathogenesis of allergic asthma.     

Protective immunity to Mycobacterium tuberculosis infection by chemokine and cytokine conditioned CFP-10 differentiated dendritic cells

Background

Dendritic cells (DCs) play major roles in mediating immune responses to mycobacteria. A crucial aspect of this is the priming of T cells via chemokines and cytokines. In this study we investigated the roles of chemokines RANTES and IP-10 in regulating protective responses from Mycobacterium tuberculosis (M. tb) 10 kDa Culture Filtrate Protein-10 (CFP-10) differentiated DCs (CFP10-DCs).

Methods and Findings

Infection of CFP10-DCs with mycobacteria down-modulated RANTES and IP-10 levels. Pathway specific microarray analyses showed that in addition to RANTES and IP-10, mycobacteria infected CFP10-DCs showed reduced expression of many Th1 promoting chemokines and chemokine receptors. Importantly, T cells co-cultured with RANTES and IP-10 conditioned CFP10-DCs mediated killing of mycobacteria from infected macrophages. Similarly, T cells recruited by RANTES and IP-10 conditioned CFP10-DCs mediated significant killing of mycobacteria from infected macrophages. IFN-gamma treatment of CFP10-DCs restored RANTES and IP-10 levels and T cells activated by these DCs mediated significant killing of virulent M. tb inside macrophages. Adoptive transfer of either RANTES and IP-10 or IL-12 and IFN-gamma conditioned CFP10-DCs cleared an established M. tb infection in mice. The extent of clearance was similar to that obtained with drug treatment.

Conclusions

These results indicate that chemokine and cytokine secretion by DCs differentiated by M. tb antigens such as CFP-10 play major roles in regulating protective immune responses at sites of infection.     

Increased Th1 activity in patients with coronary artery disease

BACKGROUND: Atherosclerotic lesions are mainly composed of macrophages and T lymphocytes. Specific T helper type 1 (Th1) cytokines and interferon gamma (IFN-gamma) inducible chemokines have been shown to be present in these lesions, modulating the local immunologic response. To explore whether this increase in Th1 activity could also be detected in circulating cells indicating a systemic activation, we studied the peripheral expression of Th1 cytokines and chemokines in patients with coronary artery disease and controls. METHODS AND RESULTS: Fifty patients with coronary artery disease (25 with unstable angina and 25 with stable angina) and 10 controls were studied. Serum interleukin (IL)-12 and IFN-gamma and the expression of IFN-gamma inducible chemokines IP-10, Mig and their receptor CXCR3 in peripheral cells were analyzed. Serum IL-12 and intracellular expression of IFN-gamma were significantly elevated in patients with unstable angina. An enhanced expression of IFN-gamma chemokines IP-10, Mig and CXCR3 in patients with stable angina was also observed. CONCLUSIONS: This study demonstrates an increased systemic inflammatory activity in patients with coronary heart disease with a predominant Th1 response, particularly in patients with unstable angina, suggesting an important role played by this polarization in plaque formation and rupture.     

Targeting the function of IFN-gamma-inducible protein 10 suppresses ongoing adjuvant arthritis

IFN-gamma-inducible protein 10 (IP-10) is a CXC chemokine that is thought to manifest a proinflammatory role because it stimulates the directional migration of activated T cells, particularly Th1 cells. It is an open question whether this chemokine is also directly involved in T cell polarization. We show here that during the course of adjuvant-induced arthritis the immune system mounts a notable Ab titer against self-IP-10. Upon the administration of naked DNA encoding IP-10, this titer rapidly accelerates to provide protective immunity. Self-specific Ab to IP-10 developed in protected animals, as well as neutralizing Ab to IP-10 that we have generated in rabbits, could inhibit leukocyte migration, alter the in vivo and in vitro Th1/Th2 balance toward low IFN-gamma, low TNF-alpha, high IL-4-producing T cells, and adoptively transfer disease suppression. This not only demonstrates the pivotal role of this chemokine in T cell polarization during experimentally induced arthritis but also suggests a practical way to interfere in the regulation of disease to provide protective immunity. From the basic science perspective, this study challenges the paradigm of in vivo redundancy. After all, we did not neutralize the activity of other chemokines that bind CXCR3 (i.e., macrophage-induced gene and IFN-inducible T cell alpha chemoattractant) and yet significantly blocked not only adjuvant-induced arthritis but also the in vivo competence to mount delayed-type hypersensitivity.     

Roxithromycin downmodulates Th2 chemokine production by keratinocytes and chemokine receptor expression on Th2 cells: its dual inhibitory effects on the ligands and the receptors

Roxithromycin (RXM), an anti-bacterial macrolide, has various immunomodulatory activities. To investigate the ability of RXM to downregulate skin-infiltration of T-lymphocytes, we examined the effects of RXM on keratinocyte production of chemokines and T cell expression of chemokine receptors. Normal human and HaCaT keratinocytes were cultured with RXM and stimulants. RXM at 1 or 10 microM significantly suppressed the production/expression of Th2 chemokines MDC and TARC in these keratinocytes, but the production of IP-10 was not affected. The effect of RXM on T-cell expression of the corresponding chemokine receptors was also tested in Th2-rich peripheral blood lymphocytes. The IL-2-enhanced expression level of Th2 chemokine receptor CCR4 was decreased by RXM at 10 microM, whereas the expression of CXCR3 was unchanged. Thus, RXM downmodulates both the production and receptor expression of Th2 but not Th1 chemokines involved in cutaneous immunity, suggesting its beneficial therapeutic effects on Th2-mediated or allergic skin disorders.     

IFN-gamma is necessary but not sufficient for anti-CD40 antibody-mediated inhibition of the Th2 response to Schistosoma mansoni eggs

The injection of Schistosoma mansoni eggs into the footpads of mice results in a localized Th2 cytokine response and tissue eosinophilia. We examined whether treatment with CD40-activating Abs would block the development of Th2 cytokine responses and eosinophilic tissue pathology in this model. Seven days after C57BL/6 mice were injected with eggs and the FGK45 anti-CD40 Ab, Ag-specific synthesis of IL-4, IL-5, and IL-13 in lymph node culture was reduced (>10-fold) relative to control mice treated with eggs and rat IgG. In contrast, IFN-gamma and IL-12 were increased in both culture supernatants and in the serum. Similar changes in lymph node cytokine mRNA were observed in vivo, and tissue eosinophilia was reduced nearly 20-fold. Th2 cytokine responses in anti-CD40-treated IFN-gamma-/- and IL-12 p40-/- C57BL/6 mice were unaffected, although anti-CD40 induced high levels of systemic and local IFN-gamma production in both wild-type and IL-12 p40-/- mice. We conclude that CD40-activating treatments strongly reverse the immune phenotype generated in response to a classic, Th2-biasing stimulus and stimulate IFN-gamma through a novel IL-12-independent pathway. This model for Th1-deviating immune therapy may have relevance to the treatment of Th2-dependent diseases in general.     

Mice with a selective deletion of the CC chemokine receptors 5 or 2 are protected from dextran sodium sulfate-mediated colitis: lack of CC chemokine receptor 5 expression results in a NK1.1+ lymphocyte-associated Th2-type immune response in the intestine

The chemokine receptors CCR2 and CCR5 and their respective ligands regulate leukocyte chemotaxis and activation. To determine the role of these chemokine receptors in the regulation of the intestinal immune response, we induced colitis in CCR2- and CCR5-deficient mice by continuous oral administration of dextran sodium sulfate (DSS). Both CCR2- and CCR5-deficient mice were susceptible to DSS-induced intestinal inflammation. The lack of CCR2 or CCR5 did not reduce the DSS-induced migration of macrophages into the colonic lamina propria. However, both CCR5-deficient mice and, to a lesser degree, CCR2-deficient mice were protected from DSS-induced intestinal adhesions and mucosal ulcerations. CCR5-deficient mice were characterized by a greater relative infiltration of CD4+ and NK1.1+ lymphocyte in the colonic lamina propria when compared to wild-type and CCR2-deficient mice. In CCR5-deficient mice, mucosal mRNA expression of IL-4, IL-5, and IL-10 was increased, whereas that of IFN-gamma was decreased, corresponding to a Th2 pattern of T cell activation. In CCR2-deficient mice, the infiltration of Th2-type T cells in the lamina propria was absent, but increased levels of IL-10 and decreased levels of IFN-gamma may have down regulated mucosal inflammation. Our data indicate that CCR5 may be critical for the promotion of intestinal Th1-type immune responses in mice.     

Matrix metalloproteinase-9 deficiency results in enhanced allergen-induced airway inflammation

Matrix metalloproteinases (MMPs) are a large family of endopeptidases that proteolytically degrade extracellular matrix. Many different cells produce MMP-9, and levels have been shown to be up-regulated in patients with allergic asthma. The aim of this study was to investigate the in vivo role of MMP-9 during allergen-induced airway inflammation. Acute allergic pulmonary eosinophilia was established in MMP-9 knockout (KO) and wild-type (WT) control mice by sensitization and challenge with OVA. Cell recruitment was significantly increased in both bronchoalveolar lavage (BAL) and lung tissue compartments in MMP-9 KO mice compared with WT mice. This heightened cell recruitment was primarily due to increased eosinophils and Th2 cells in the BAL and lung tissue of MMP-9 KO mice in comparison with WT controls. Moreover, levels of the Th2 cytokines, IL-4 and IL-13, and the chemokines eotaxin/CCL11 and macrophage-derived chemokine/CCL22 were substantially increased in MMP-9 KO mice compared with WT after OVA challenge. Resolution of eosinophilia was similar between MMP-9 KO and WT mice, but Th2 cells persisted in BAL and lungs of MMP-9 KO mice for longer than in WT mice. Our results indicate that MMP-9 is critically involved in the recruitment of eosinophils and Th2 cells to the lung following allergen challenge, and suggest that MMP-9 plays a role in the development of Th2 responses to allergen.     

Thymic stromal lymphopoietin expression is increased in asthmatic airways and correlates with expression of Th2-attracting chemokines and disease severity

Thymic stromal lymphopoietin (TSLP) is said to increase expression of chemokines attracting Th2 T cells. We hypothesized that asthma is characterized by elevated bronchial mucosal expression of TSLP and Th2-attracting, but not Th1-attracting, chemokines as compared with controls, with selective accumulation of cells bearing receptors for these chemokines. We used in situ hybridization and immunohistochemistry to examine the expression and cellular provenance of TSLP, Th2-attracting (thymus and activation-regulated chemokine (TARC)/CCL17, macrophage-derived chemokine (MDC)/CCL22, I-309/CCL1) and Th1-attracting (IFN-gamma-inducible protein 10 (IP-10)/CXCL10, IFN-inducible T cell alpha-chemoattractant (I-TAC)/CXCL11) chemokines and expression of their receptors CCR4, CCR8, and CXCR3 in bronchial biopsies from 20 asthmatics and 15 normal controls. The numbers of cells within the bronchial epithelium and submucosa expressing mRNA for TSLP, TARC/CCL17, MDC/CCL22, and IP-10/CXCL10, but not I-TAC/CXCL11 and I-309/CCL1, were significantly increased in asthmatics as compared with controls (p 相似文献   

CD4+ Th2 response induced by Schistosoma mansoni eggs develops rapidly, through an early, transient, Th0-like stage.

Data from recent studies of murine schistosomiasis mansoni have indicated that certain characteristics of this infection, such as eosinophilia and elevated IgE, are due largely to the induction of Th2-like immune responses by parasite ova. The present study was designed to examine more closely the genesis and development of these skewed Th responses to schistosome eggs. Accordingly, eggs isolated from infected mice were injected s.c. into normal mice. After inoculation, draining lymph node (LN) cells were recovered, phenotyped, and tested for their ability to proliferate and secrete IL-2 and IFN-gamma (as markers of Th1 function) and IL-4, IL-5, and IL-10 (Th2 cytokines). The results show a maximal LN enlargement of 40- to 100-fold by day 3 after egg inoculation. The CD4/CD8/B cell ratio at this time is similar to that in LN from normal mice, but increases in numbers of cells expressing very low levels of MEL-14 and high levels of Pgp-1 are evident by days 3 and 10, respectively. Surprisingly, the initial detectable Ag-specific response to schistosome eggs, observed at day 1, is the production of IFN-gamma. By day 3, LN cells are capable of proliferating and making IFN-gamma plus IL-2, IL-4, IL-5, and IL-10 when stimulated with soluble egg Ag and, therefore, appear Th0-like. After 7 to 10 days, IFN-gamma production is severely depressed but the response continues to be characterized by IL-4, IL-5, IL-10, and IL-2. Depletion studies indicate that CD4 cells are the major population responsible for Ag-mediated proliferation and cytokine production. Results show that schistosome eggs are autonomous inducers of vigorous Th2-like effector responses. Further, our data, from a system that utilizes an in vivo priming step, support the contentions that skewed Th responses develop via an intermediate Th0 stage is accompanied by a loss of the MEL-14 surface marker and an increase in Pgp-1 expression.     

Chemokine receptor expression and function in CD4+ T lymphocytes with regulatory activity

We have investigated the chemokine receptor expression and migratory behavior of a new subset of nickel-specific skin-homing regulatory CD4(+) T cells (Th(IL-10)) releasing high levels of IL-10, low IFN-gamma, and undetectable IL-4. These cells inhibit in a IL-10-dependent manner the capacity of dendritic cells to activate nickel-specific Tc1 and Th1 lymphocytes. RNase protection assay and FACS analysis revealed the expression of a vast repertoire of chemokine receptors on resting Th(IL-10), including the Th1-associated CXCR3 and CCR5, and the Th2-associated CCR3, CCR4, and CCR8, the latter at higher levels compared with Th2 cells. The most active chemokines for resting Th(IL-10), in terms of calcium mobilization and in vitro migration, were in order of potency: CCL2 (monocyte chemoattractant protein-1, CCR2 ligand), CCL4 (macrophage-inflammatory protein-1beta, CCR5 ligand), CCL3 (macrophage-inflammatory protein-1alpha, CCR1/5 ligand), CCL17 (thymus and activation-regulated chemokine, CCR4 ligand), CCL1 (I-309, CCR8 ligand), CXCL12 (stromal-derived factor-1, CXCR4), and CCL11 (eotaxin, CCR3 ligand). Consistent with receptor expression down-regulation, activated Th(IL-10) exhibited a reduced or absent response to most chemokines, but retained a significant migratory capacity to I-309, monocyte chemoattractant protein-1, and thymus and activation-regulated chemokine. I-309, which was ineffective on Th1 lymphocytes, attracted more efficiently Th(IL-10) than Th2 cells. I-309 and CCR8 mRNAs were not detected in unaffected skin and were up-regulated at the skin site of nickel-allergic reaction, with an earlier expression kinetics compared with IL-10 and IL-4. Results indicate that skin-homing regulatory Th(IL-10) lymphocytes coexpress functional Th1- and Th2-associated chemokine receptors, and that CCR8/I-309-driven recruitment of both resting and activated Th(IL-10) cells may be critically involved in the regulation of Th1-mediated skin allergic disorders.