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S Sur

Publications and source records attributed to S Sur.

At least 19 recordsLinked to original sources
PubMed2002

Interleukin-12 inhibits eosinophil differentiation from bone marrow stem cells in an interferon-gamma-dependent manner in a mouse model of asthma.

BACKGROUND: Intrapulmonary administration of IL-12 has been shown to inhibit the number of eosinophils in lung murine models of asthma, but the precise mechanism of this inhibition has not been reported. The purpose of this study was to examine whether IL-12 treatment inhibits bone marrow eosinophilopoiesis, and to elucidate the role of IFN-gamma in this process. OBJECTIVE: To elucidate the in vivo and in vitro effects of IL-12 on eosinophil differentiation from murine bone marrow (BM) stem cells, and to examine the mechanistic role of IFN-gamma in this process. METHODS: Allergen-sensitized BALB/c mice were administered low doses of intranasal IL-12 at the time of allergen challenge, and the number of eosinophils in BM was determined 3 days later. The direct actions of IL-12 on eosinophil differentiation from BM cells were determined in vitro. The mechanistic role of IFN-gamma was assessed by measuring IFN-gamma induction by IL-12 in BM cell cultures, and through the use of IFN-gamma KO mice. RESULTS: Treatment of allergic mice with intrapulmonary IL-12 (1 ng or 10 ng) reduced eosinophils in BM by 43%. Culture of BM cells from allergen-sensitized mice with IL-3 + IL-5 induced eosinophil differentiation in vitro. Addition of IL-12 to these cultures inhibited eosinophil differentiation, with maximal inhibition (45%) occurring at 10 ng/mL IL-12 concentration. IL-12 induced IFN-gamma production from BM cultures, and failed to inhibit eosinophil differentiation in IFN-gamma-knockout mice, indicating a critical mechanistic role for IFN-gamma. CONCLUSION: This study demonstrates that IL-12 selectively inhibits BM eosinophilopoiesis, and that this effect is mediated by IFN-gamma. Intrapulmonary IL-12 has suppressive effects on BM eosinophilopoiesis that may represent a novel mechanism contributing to the anti-eosinophilic effects of IL-12 in allergic airway disease.

Animals↗
PubMed2002

Removal of bronchoalveolar cells augments the late eosinophilic response to segmental allergen challenge.

BACKGROUND: In patients with quiescent asthma, macrophages are the most prevalent cells recovered by bronchoalveolar lavage (BAL). Through activation via their FcepsilonRII receptors or by acting as antigen-presenting cells, macrophages could, in theory, promote the late airway response to allergen. OBJECTIVE: In order to investigate the importance of macrophages and other airway luminal cells in inducing the late airway response, a novel washout experiment was designed. METHODS: Five patients with ragweed-allergic asthma underwent bronchoscopy and segmental bronchial challenge with either normal saline or short ragweed extract in two segments of one lung. In a third segment of the opposite lung, 12 successive BALs (25 mL each) were performed, followed by challenge with an identical dose of short ragweed (washed-challenged segment). After 24 h, all three challenged segments underwent BAL. RESULTS: Initially, in the washed-challenged segment, over 80% (mean 80.4%, range 68-88%) of the recoverable airway dwelling cells were removed. Unexpectedly, 24 h later these same washed-challenged segments contained more eosinophils in the BAL than the challenged segments from the opposite lung (P = 0.033). CONCLUSIONS: Removing the majority of airway luminal cells followed by allergen bronchoprovocation increased the number of eosinophils recovered 24 h after challenge. Our results suggest that in quiescent allergic asthma, the airway luminal cells are protective and attenuate the late eosinophilic response to allergen challenge.

Adult↗
PubMed2001

IL-10 gene knockout attenuates allergen-induced airway hyperresponsiveness in C57BL/6 mice.

Intratracheal administration of interleukin-10 (IL-10) has been reported to inhibit allergic inflammation but augment airway hyperresponsiveness (AHR). In the present study, airway and smooth muscle responsiveness to methacholine (MCh) were compared in wild-type (WT) and IL-10-deficient (IL-10-KO) mice to investigate the role of endogenous IL-10 in AHR development. Naive WT and IL-10-KO mice exhibited similar dose-dependent increases in airway resistance (Raw) to intravenous MCh. Sensitization and challenge with ragweed (RW) induced a twofold increase in responsiveness to intravenous MCh in WT mice, but hyperresponsiveness was not observed in similarly treated IL-10-KO mice. Likewise, tracheal rings from RW-sensitized and -challenged WT mice exhibited a fourfold greater responsiveness to MCh than IL-10-KO tracheal preparations. Measurements of airway constriction by whole body plethysmography further supported the Raw and tracheal ring data (i.e., AHR was not observed in the absence of IL-10). Interestingly, factors previously implicated in the development of AHR, including IL-4, IL-5, IL-13, IgA, IgG1, IgE, eosinophilia, and lymphocyte recruitment to the airways, were upregulated in the IL-10-KO mice. Treatment with recombinant murine IL-10 at the time of allergen challenge reduced the magnitude of inflammation but reinstated AHR development in IL-10-KO mice. Adoptive transfer of mononuclear splenocytes to IL-10-sufficient severe combined immunodeficient mice indicated that lymphocytes were an important source of the IL-10 impacting AHR development. These results provide evidence that IL-10 expression promotes the development of allergen-induced smooth muscle hyperresponsiveness.

Adoptive Transfer↗
PubMed2000

The differential role of extracellular signal-regulated kinases and p38 mitogen-activated protein kinase in eosinophil functions.

The activation of eosinophils by cytokines is a major event in the pathogenesis of allergic diseases. We have investigated the activation of mitogen-activated protein (MAP) kinases and their functional relevance in eosinophil differentiation, survival, degranulation, and cytokine production. IL-5 induced phosphorylation and activation of extracellular signal-regulated kinases (ERK) and p38 MAP kinases in eosinophils. PD98059, a MAP/ERK kinase inhibitor, blocked phosphorylation of ERK1/2 in a dose-dependent manner. SB202190, a p38 inhibitor, blocked p38-dependent phosphorylation of activating transcription factor-2. To study the importance of the MAP kinases on eosinophil differentiation, we cultured mouse bone marrow cells with IL-3 and IL-5 in the presence of the inhibitors. SB202190 dramatically inhibited eosinophil differentiation by 71%. PD98059 was less potent and reduced eosinophil differentiation by 28%. Both inhibitors marginally inhibited eosinophil survival only at the highest doses. Prolonged incubation of eosinophils with IL-5 induced significant eosinophil-derived neurotoxin release. Both PD98059 and SB202190 nearly completely inhibited (87% and 100% inhibition, respectively) IL-5-stimulated eosinophil-derived neurotoxin release in a dose-dependent manner. Next, we examined the effect of the MAP kinase inhibitors on eosinophil production of the cytokine macrophage-inflammatory protein (MIP)-1alpha. PD98059 blocked C5a- but not ionomycin-induced MIP-1alpha production (59% inhibition at 50 microM concentration). In contrast, SB202190 nearly completely inhibited (99%) C5a-induced MIP-1alpha production. Further, it blocked ionomycin-stimulated production by 66%. Our results suggest that both p38 and ERK1/2 MAP kinases play an important role in eosinophil differentiation, cytokine production, and degranulation. The p38 MAP kinase plays a greater role than ERK1/2 in eosinophil differentiation and cytokine production.

Animals↗
PubMed2000

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.

Adjuvants, Immunologic↗
PubMed2000

Mucosal IL-12 is more effective than systemic IL-12 in augmenting IFN-gamma expression and inhibiting allergic lung eosinophilia in murine lungs.

The relative efficacy of mucosal (intratracheal) and systemic (intraperitoneal) delivery of interleukin (IL)-12 was evaluated in a mouse model of allergic lung eosinophilia. Mucosal administration of IL-12 achieved 100- to 600-fold higher bronchoalveolar lavage (BAL) levels of IL-12, but 2- to 10-fold lower serum levels compared to systemic administration. Whereas both mucosal and systemic IL-12 inhibited BAL eosinophil recruitment at high doses (100-1000 ng), only mucosal IL-12 was effective at low doses (1-10 ng). Mucosal, but not systemic, administration of 1000 ng of IL-12 increased interferon (IFN)-gamma expression in BAL cells. In a model of ongoing eosinophilic inflammation, when mucosal or systemic IL-12 doses were initiated prior to peak eosinophilia, further eosinophil recruitment was inhibited. However, when IL-12 treatment was initiated after peak eosinophil recruitment occurred, recovery from eosinophilic inflammation was not facilitated. Our findings are the first to demonstrate that locally administered IL-12 inhibits eosinophil recruitment at 100-fold lower doses than systemic IL-12. The most likely mechanism of this enhanced inhibitory activity is a sustained increase in lung levels of IL-12 that augments IFN-gamma production from BAL cells. We suggest that future studies should evaluate the efficacy of low doses of nebulized IL-12 in inhibiting eosinophilic lung inflammation in asthma.

Adjuvants, Immunologic↗
PubMed2000

Mucosal IL-12 inhibits airway reactivity to methacholine and respiratory failure in murine asthma.

The worldwide incidence, prevalence, and fatality rates from asthma are increasing despite currently available therapeutic modalities. Systemic administration of interleukin (IL)-12 has been shown to inhibit airway reactivity in murine models of asthma, but the required dosage is high and may be toxic. This study tested the hypothesis that IL-12 administered directly into the lungs is more effective in inhibiting airway reactivity than systemically administered IL-12, allowing lower doses to be used. A low dose (10 ng) of IL-12 was delivered either intratracheally (mucosal delivery) or intraperitoneally (systemic delivery) at the time of ragweed (RW) challenge in mice sensitized to RW. Basal airway resistance and airway reactivity to methacholine were measured 3 days after RW challenge. Compared to phosphate-buffered saline (PBS) challenge of RW sensitized mice, RW challenge increased basal resistance and the slope of the methacholine dose-response curve. Methacholine challenge of RW-challenged mice also induced premature respiratory failure (respiratory rate < 150/min, tidal volume < 0.15 mL) in some animals. Administration of mucosal or systemic IL-12 at the time of RW challenge decreased basal airway resistance. However, only mucosal IL-12 decreased airway reactivity and inhibited respiratory failure during methacholine challenge. These findings indicate that mucosal delivery of a low dose of IL-12 is more effective than systemic IL-12 in inhibiting airway reactivity and respiratory failure in a mouse model of asthma.

Adjuvants, Immunologic↗
PubMed2000

IL-10 reduces Th2 cytokine production and eosinophilia but augments airway reactivity in allergic mice.

We investigated the effects of interleukin (IL)-10 administration on allergen-induced Th2 cytokine production, eosinophilic inflammation, and airway reactivity. Mice were sensitized by intraperitoneal injection of ragweed (RW) adsorbed to Alum and challenged by intratracheal instillation of the allergen. Sensitization and challenge with RW increased concentrations of IL-10 in bronchoalveolar lavage (BAL) fluid from undetectable levels to 60 pg/ml over 72 h. Intratracheal instillation of 25 ng of recombinant murine IL-10 at the time of RW challenge further elevated BAL fluid IL-10 concentration to 440 pg/ml but decreased BAL fluid IL-4, IL-5, and interferon-gamma levels by 40-85% and eosinophil numbers by 70% (P < 0.0001). Unexpectedly, the same IL-10 treatment increased airway reactivity to methacholine in spontaneously breathing mice that had been sensitized and challenged with RW (P < 0.001). IL-10 treatment in naive animals or RW-sensitized mice challenged with PBS failed to increase airway reactivity, demonstrating that IL-10 induces an increase in airway reactivity only when it is administered in conjunction with allergic sensitization and challenge. The results demonstrate that IL-10 reduces Th2 cytokine levels and eosinophilic inflammation but augments airway hyperreactivity. Thus, despite its potent anti-inflammatory activity, IL-10 could contribute to the decline in pulmonary function observed in asthma.

Animals↗
PubMed1999

A novel Lyn-binding peptide inhibitor blocks eosinophil differentiation, survival, and airway eosinophilic inflammation.

Receptor antagonists block all receptor-coupled signaling pathways indiscriminately. We introduce a novel class of peptide inhibitors that is designed to block a specific signal from a receptor while keeping other signals intact. This concept was tested in the model of IL-5 signaling via Lyn kinase. We have previously mapped the Lyn-binding site of the IL-5/GM-CSF receptor common beta (beta c) subunit. In the present study, we designed a peptide inhibitor using the Lyn-binding sequence. The peptide was N-stearated to enable cellular internalization. The stearated peptide blocked the binding of Lyn to the beta c receptor and the activation of Lyn. The lipopeptide did not affect the activation of Janus kinase 2 or its association with beta c. The inhibitor blocked the Lyn-dependent functions of IL-5 in vitro (e.g., eosinophil differentiation from stem cells and eosinophil survival). It did not affect eosinophil degranulation. When applied in vivo, the Lyn-binding peptide significantly inhibited airway eosinophil influx in a mouse model of asthma. The lipopeptide had no effect on basophil histamine release or on the proliferation of B cells and T cells. To our knowledge, this is the first report on an inhibitor of IL-5 that blocks eosinophil differentiation, survival, and airway eosinophilic inflammation. This novel strategy to develop peptide inhibitors can be applied to other receptors.

Amino Acid Sequence↗
PubMed1999

Long term prevention of allergic lung inflammation in a mouse model of asthma by CpG oligodeoxynucleotides.

Asthma is an inflammatory disease of the airways that is induced by Th2 cytokines and inhibited by Th1 cytokines. Despite a steady increase in the incidence, morbidity, and mortality from asthma, no current treatment can reduce or prevent asthma for a prolonged period. We examined the ability of unmethylated CpG oligodeoxynucleotides (ODN), which are potent inducers of Th1 cytokines, to prevent the inflammatory and physiological manifestations of asthma in mice sensitized to ragweed allergen. Administration of CpG ODN 48 h before allergen challenge increased the ratio of IFN-gamma to IL-4 secreting cells, diminished allergen-induced eosinophil recruitment, and decreased the number of ragweed allergen-specific IgE-producing cells. These effects of CpG ODN were sustained for at least 6 wk after its administration. Furthermore, there was a vigorous Th1 memory response to the recall Ag, inhibition of peribronchial and perivascular lung inflammation, and inhibition of bronchial hyperresponsiveness 6 wk after administration of CpG ODN. Administration of CpG ODN in IFN-gamma -/- mice failed to inhibit eosinophil recruitment, indicating a critical role of IFN-gamma in mediating these effects. This is the first report of a treatment that inhibits allergic lung inflammation in presensitized animals for a prolonged period and thus has relevance to the development of an effective long term treatment for asthma.

Allergens↗
PubMed1998

Localization of eosinophil-derived neurotoxin and eosinophil cationic protein in neutrophilic leukocytes.

Eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) are generally regarded as eosinophil-specific proteins. We tested whether EDN and ECP are present in mature neutrophils. By indirect immunofluorescence, both eosinophils and neutrophils stained with antibodies to EDN and ECP. Lysates of purified (<0.1% eosinophil contamination) neutrophils contained EDN, 112+/-4 ng/10(6) cells, and ECP, 163+/-2 ng/10(6) cells, whereas eosinophil major basic protein (MBP) was not detectable. Electron microscopic examination of immunogold-labeled buffy coat cells stained with EDN antibody showed that EDN is localized to neutrophil granules. Finally, EDN mRNA was detected in lysates of highly purified neutrophils (0.001% eosinophil contamination) by the reverse transcription-polymerase chain reaction. We conclude that proteins that are either identical to or immunologically cross-reactive with EDN and ECP are present in neutrophils and that EDN is synthesized and localized to neutrophil granules. Thus, caution must be exercised in interpreting the presence of EDN and ECP as specific markers of eosinophil-associated inflammation in human disease.

Biopsy↗
PubMed1996

Immunomodulatory effects of IL-12 on allergic lung inflammation depend on timing of doses.

We investigated the effects of IL-12 on a murine model of allergic lung inflammation. Administration of IL-12 was timed to interfere with either allergic sensitization (early dosage) or the hypersensitivity inflammatory response in the lung (late dosage), or both (early and late dosages). Comparisons of IL-12- and PBS-treated animals within each treatment group revealed several noticeable effects of IL-12. Early dosage, and the combination of early and late dosages, strikingly decreased ragweed-specific serum IgE, tracheal ring reactivity to acetylcholine, and BAL eosinophilia following allergen challenge. In contrast, late dosage had no effect on IgE levels and only a minimal effect on tracheal ring reactivity, but had a modest effect on recruitment of eosinophils. Early dosage down-regulated IL-5 and IL-10, but did not alter IL-4 or IFN-gamma expression. Late dosage down-regulated IL-5, up-regulated IL-10 and IFN-gamma, but did not change IL-4 expression. The combination of early and late dosage down-regulated IL-4, IL-5, and IL-10 expression, but increased IFN-gamma expression and production in the BAL cells and fluids. Taken together, these results indicate that IL-12 has potent immunomodulatory effects on allergic lung inflammation that depend on the timing of IL-12 administration relative to allergic sensitization and allergen challenge.

Acetylcholine↗
PubMed1996

Eosinophil recruitment is associated with IL-5, but not with RANTES, twenty-four hours after allergen challenge.

Several lines of evidence suggest that the chemokine RANTES may play a role in eosinophilia observed during allergic inflammation. To test this hypothesis, six patients with allergic asthma were studied. After performing bronchoalveolar lavage in a lung segment (baseline), segmental bronchoprovocation was performed with saline solution in another segment and with ragweed in a third segment. Bronchoalveolar lavage was performed 24 hours later in the saline-challenged (sham) and ragweed-challenged lung segments. The bronchoalveolar lavage fluids from the baseline, sham, and ragweed segments were analyzed for cell counts and for the levels of IL-5, RANTES, and eosinophil-derived neurotoxin. IL-5 levels were elevated in the ragweed (984 +/- 588 pg/ml) compared with sham segments (2.8 +/- 0.2 pg/ml, p = 0.02). Likewise, RANTES levels were elevated in the ragweed (12.93 +/- 3.4 pg/ml) compared with the sham segments (3.05 +/- 1.19 pg/ml, p = 0.006). The IL-5 levels correlated with both eosinophil numbers (r = 0.90, p < 0.02) and eosinophil-derived neurotoxin levels (r = 0.89, p < 0.02). In contrast, RANTES levels did not correlate with either eosinophil numbers or eosinophil-derived neurotoxin levels. These results indicate that although both IL-5 and RANTES are elevated 24 hours after allergen challenge, only IL-5 correlates with eosinophil recruitment and degranulation.

Adolescent↗
PubMed1996

Lidocaine in bronchoalveolar lavage fluid (BALF) is an inhibitor of eosinophil-active cytokines.

Eosinophils and eosinophil granule proteins may play an important role in the pathogenesis of asthma. BALF from 40 patients with symptomatic asthma were analysed for cytokine activity by the eosinophil survival assay. BALF from 15 patients showed increased survival activity. Survival activities in BALF from four of these patients were almost completely blocked by anti-IL-5 MoAb, and the remaining activities were blocked by anti-granulocyte-macrophage colony-stimulating factor (GM-CSF), anti-IL-3 antibody, or both. Surprisingly, BALF samples from the other 25 patients decreased eosinophil viabilities below the levels of medium control. The inhibitory factor in these BALF was of low molecular weight, was heat-stable, was largely overcome by excess exogenously added cytokines, and was positively correlated with the concentrations of lidocaine in the BALF. Lidocaine itself inhibited eosinophil survival at concentrations less than those present in the BALF. These findings indicate that lidocaine is an inhibitor of cytokines in the eosinophil survival assay, and they suggest the need for caution in analyses of BALF containing lidocaine or other local anaesthetics.

Adult↗