Dual effect of IL-4 on resistance to systemic gram-negative infection and production of TNF-alpha

To determine the effect of interleukin 4 (IL-4) administration in a live sepsis model characterised by high-level production of tumour necrosis factor a (TNF-alpha), mice infected systemically with lethal or sublethal inocula of Pseudomonas aeruginosa were given the recombinant cytokine at different times before infection. Improved survival and decreased TNF-alpha production were observed in lethally infected mice treated with the cytokine 1 day before challenge. In contrast, increased mortality and overproduction of TNF-alpha were observed in sublethally infected mice given IL-4 at the time of infection.     

Cold stress-induced modulation of inflammatory responses and intracerebral cytokine mRNA expression in acute murine toxoplasmosis

The effects of a physical stressor, cold water stress (CWS), within the central nervous system were investigated in the acute phase of infection with Toxoplasma gondii. Female BALB/c mice were subjected to CWS for 5 min each day for 8 days prior to oral infection with 20 cysts of the low virulent ME 49 strain. Animals were killed at 10-day intervals to detect inflammation, gliosis, and expression of intracerebral cytokine mRNAs. Zones of inflammation were detected by Nissl staining and gliosis by immunoreactivity to glial fibrillary acidic protein. Larger zones of inflammation and reactive astrogliosis were consistently observed in mice subjected to CWS and infected (CWS +INF) compared to control infected (INF) mice. Expression of interleukin (IL)-1beta, IL-2, IL-12, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and inducible nitric oxide synthase (iNOS) were decreased in CWS+INF mice at 10 days postinoculation (PI), followed by a gradual increase after day 20 PI. This was in contrast to increased expression of these cytokines at 10 days PI in INF mice with a gradual decline thereafter. Inflammation and astrogliosis in CWS+INF mice were associated with an increased expression of IL-1beta, IL-6, IL-12, and TNF-alpha between 20 and 30 days PI. These findings correlated with the continuous gene expression of tachyzoite surface antigen (SAG)-1 mRNA in CWS+INF mice compared to its sharp decline in INF mice after 20 days PI. These results suggest that CWS delays regulation and control of intracerebral Toxoplasma gondii during acute infection in BALB/c mice by decreasing the early expression of IFN-gamma, IL-2, TNF-alpha, iNOS, IL-1beta, and IL-12, while increasing the expression of IL-6, a counterregulatory cytokine.     

Cytokine production of stimulated whole blood cultures in rheumatoid arthritis patients receiving short-term infliximab therapy

Patients with rheumatoid arthritis (RA) treated with anti-tumor necrosis factor (TNF) strategies have an increased susceptibility to infections, especially those caused by intracellular pathogens. In this study we assessed the cytokine production capacity in patients with RA and we further investigated whether anti-TNF therapy modulates the production of pro-inflammatory cytokines involved in the resistance against infections. Whole blood cultures from 10 RA patients and 10 healthy controls were stimulated with heat-killed Candida albicans, Salmonella typhimurium, Staphyloccocus aureus, Aspergillus fumigatus or Mycobacterium tuberculosis and production of interleukin (IL)-1beta, IL-6, IL-10, interferon (IFN)-gamma and TNF-alpha was measured. Before anti-TNF therapy, whole blood cultures from RA patients released significantly less IFN-gamma than healthy controls after stimulation with all tested microorganisms. Short-term anti-TNF therapy did not have an inhibitory effect on the release of the cytokines tested. We conclude that cells of patients with RA have a strongly reduced production capacity of IFN-gamma after bacterial challenge. Although short-term therapy with anti-TNF agents did not further decrease the release of other proinflammatory cytokines, the combination of defective IFN-gamma production in basal conditions and TNF neutralization during anti-TNF therapy is likely to be responsible for the higher susceptibility to infections in patients with RA.     

Immunological and pathological aspects of respiratory tract infection with Stenotrophomonas maltophilia in BALB/c mice

A comprehensive study on the production of inflammatory mediators in the lungs of BALB/c mice following infection with Stenotrophomonas maltophilia was conducted. The levels of pro-inflammatory cytokines, tumor necrosis factor alpha (TNF-alpha) and Interleukin-1beta (IL-1 beta) was raised in the lungs of infected mice compared to control. The production of anti-inflammatory cytokine IL-10 was slightly delayed. Its peak level was on 2nd day whereas the peak of pro-inflammatory cytokines was observed on day one after intranasal challenge. This was accompanied with a rise in Myeloperoxidase (MPO) and Malondialdehyde (MDA) on day one. The increase in MPO levels matched with histopathological observations as neutrophils infiltration was detected on the first day. Alveolar macrophages (AMs) obtained from infected animals showed higher rate of uptake and killing when exposed to bacteria in vitro compared to similar experiment conducted with AMs from normal mice (control). This suggests that AMs were more efficient in cleaning the bacteria. The nitric oxide (NO) production though started early during infection but reached its maximum on 3rd day. No mortality was observed among the infected animals and infection was resolved by 5th post infection day. No drastic changes in the lung tissue were observed on histopathological examination.     

The role of tumor necrosis factor and interleukin-1 in forming resistance in experimental Q fever]

Preliminary injections of human recombinant tumor necrosis factor (TNF-alpha) and interleukin 1 (IL-1 beta) increases the resistance of guinea pigs to Coxiella burnetii. The increase of this resistance depends on the dose of cytokines and the time of their inoculation.     

Effects of beta-glucan extracted from Saccharomyces cerevisiae on humoral and cellular immunity in weaned piglets

Twenty-four barrows were used to investigate the effects of beta-glucan on immune function in weaned piglets. Pigs (8.09 +/- 0.20 kg, 28 d of age) were fed a diet without or with supplemented beta-glucan (50 mg/kg feed). All pigs were injected with ovalbumin (OVA) on day 14 to investigate their humoral immune response. On day 28, lymphocytes were isolated from all pigs to determine the effects of beta-glucan on cellular immunity of pigs in vitro. Lymphocytes from six pigs of each group were incubated with 16 microg lipopolysaccharide (LPS) per ml culture medium, the remainder with an equivalent volume of culture medium alone. Samples were collected at 0, 3, 6, 12, 18, 24, and 48 h after LPS addition for determination of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interleukin-10 (IL-10). On day 31, six pigs of each group were injected with either LPS (25 microg/kg BW) or an equivalent amount of sterile saline. Blood samples were collected at 3 h after LPS injection for analysis of IL-6, TNF-alpha, and IL-10 in plasma. The results indicated that dietary beta-glucan enhanced pig antibody response to OVA only in the first week after injection. In vitro, the increases of IL-6 and TNF-alpha in culture medium were partially dampened in pigs supplemented with beta-glucan when their lymphocytes were incubated with LPS, whereas the increase of IL-10 was potentiated. In vivo, dietary beta-glucan attenuated the increase of plasma IL-6 and TNF-alpha, and enhanced the increase of plasma IL-10 when pigs were challenged with LPS. These results demonstrate that beta-glucan can improve the humoral immunity of pigs and modulate cellular immunity of pigs by mitigating the elevation of pro-inflammatory cytokines and enhancing the increase of anti-inflammatory cytokines after an immunological challenge.     

The effect of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta and IL-6 on chorioamnion secretion of prostaglandins (PG)F 2 alpha and E2 in pigs

The aim of the present study was to determine the effect of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) on prostaglandin (PG)F(2 alpha) and PGE(2) secretion as well as cyclooxygenase-2 (COX-2) protein expression in chorioamnion collected on days 25, 30 and 40 of pregnancy in pigs. Fetal membrane slices were incubated for 16 h with TNF-alpha, IL-1 beta, IL-6 (1 or 10 ng/ml of medium) or two combinations of the three cytokines (1 or 10 ng/ml of each cytokine per combination). We demonstrated the stimulatory effect of TNF-alpha, IL-1 beta and/or IL-6 on PGF(2 alpha) and PGE(2) secretion by the porcine fetal membranes. The medium content of these PGs depended on the cytokine type, treatment dose and day of pregnancy. Cytokine stimulation of PGE(2) was more pronounced than that of PGF(2 alpha). In addition, an increase in PGF(2 alpha) and/or PGE(2) secretion was usually associated with an augmentation of COX-2 protein expression. Our results support the notion concerning the possible role of cytokines in modulating production of PGs by fetal membranes during the first trimester of gestation.     

Inhibition of inducible NO synthase by TH2 cytokines and TGF beta in rheumatoid arthritic synoviocytes: effects on nitrosothiol production.

The aim of this study was to compare the effects on NO production of IL-4, IL-10, and IL-13 with those of TGF-beta. RA synovial cells were stimulated for 24 h with IL-1 beta (1 ng/ml), TNF-alpha (500 pg/ml), IFN-gamma (10(-4)IU/ml) alone or in combination. Nitrite was determined by the Griess reaction, S-nitrosothiols by fluorescence, and inducible NO synthase (iNOS) by immunofluorescence and fluorescence activated cell sorter analysis (FACS). In other experiments, IL-4, IL-10, IL-13, and TGF beta were used at various concentrations and were added in combination with proinflammatory cytokines. The addition of IL-1 beta, TNF-alpha, and IFN-gamma together increased nitrite production: 257.5 +/- 35.8 % and S-nitrosothiol production : 413 +/- 29%, P < 0.001. None of these cytokines added alone had any significant effect. iNOS synthesis increased with NO production. IL-4, IL-10, IL-13, and TGF beta strongly decreased the NO production caused by the combination of IL-1 beta, TNF-alpha, and IFN-gamma. These results demonstrate that stimulated RA synoviocytes produce S-nitrosothiols, bioactive NO* compounds, in similar quantities to nitrite. IL-4, IL-10, IL-13, and TGF-beta decrease NO production by RA synovial cells. The anti-inflammatory properties of these cytokines may thus be due at least in part to their effect on NO metabolism.     

Ebola GP-specific monoclonal antibodies protect mice and guinea pigs from lethal Ebola virus infection

Ebola virus (EBOV) causes acute hemorrhagic fever in humans and non-human primates with mortality rates up to 90%. So far there are no effective treatments available. This study evaluates the protective efficacy of 8 monoclonal antibodies (MAbs) against Ebola glycoprotein in mice and guinea pigs. Immunocompetent mice or guinea pigs were given MAbs i.p. in various doses individually or as pools of 3-4 MAbs to test their protection against a lethal challenge with mouse- or guinea pig-adapted EBOV. Each of the 8 MAbs (100 μg) protected mice from a lethal EBOV challenge when administered 1 day before or after challenge. Seven MAbs were effective 2 days post-infection (dpi), with 1 MAb demonstrating partial protection 3 dpi. In the guinea pigs each MAb showed partial protection at 1 dpi, however the mean time to death was significantly prolonged compared to the control group. Moreover, treatment with pools of 3-4 MAbs completely protected the majority of animals, while administration at 2-3 dpi achieved 50-100% protection. This data suggests that the MAbs generated are capable of protecting both animal species against lethal Ebola virus challenge. These results indicate that MAbs particularly when used as an oligoclonal set are a potential therapeutic for post-exposure treatment of EBOV infection.     

Inflammatory cytokine production in interferon-gamma-primed mice, challenged with lipopolysaccharide. Inhibition by SK&F 86002 and interleukin-1 beta-converting enzyme inhibitor

Mice challenged with lipopolysaccharide (LPS) produce variable serum levels of pro-inflammatory cytokines, and particularly low levels of interleukin-1 beta (IL-1 beta). Interferon-gamma (IFN-gamma) has been shown to be an important mediator of bacteria-induced hypersensitivity to LPS in mice. In the present study, we show that mice pretreated with IFN-gamma exhibit an enhanced capacity to produce serum IL-1 beta, IL-1 alpha, tumour necrosis factor (TNF-alpha) as well as IL-6 in response to LPS. Priming with intraperitoneal (i.p.) injection of 15 mg rat recombinant IFN-gamma, 18 hours prior to the i.p. LPS (300 mg) challenge resulted in a 4-fold increase in the LPS-stimulated release of IL-1 beta and a 2- to 7-fold increase in the release of IL-1 alpha, TNF-alpha, as well as IL-6 into the serum. LPS induced a concentration-dependent increase in the release of IL-1 beta in isolated peritoneal macrophages from IFN-gamma-primed mice whereas macrophages from unprimed mice released minute amounts of IL-1 beta. In addition, nigericin markedly enhanced the release of IL-1 beta in unprimed mice but not in macrophages from IFN-gamma primed mice. The cytokine synthesis inhibitor SK&F 86002, administered per os (100 mg/kg), 1 hour prior to LPS challenge, strongly inhibited the rise in serum levels of the four cytokines. Furthermore, treatment with the IL-1 beta converting enzyme (ICE) specific reversible inhibitor YVAD-CHO resulted in a sharp dose- and time-dependent inhibition of IL-1 beta secretion in the serum, whereas the other cytokines were not affected. In conclusion, IFN-gamma priming strongly potentiates the release of proinflammatory cytokines in the serum of mice as compared to LPS stimulation alone, and provides therefore a useful way to test the in vivo potency and selectivity of cytokine synthesis inhibitors.     

Repeated intratracheal challenge with particulate antigen modulates murine lung cytokines

When lungs of experimental animals are repeatedly challenged with Ag, pulmonary inflammation wanes via unknown mechanisms. We hypothesized that changes in the balance of lung cytokines are responsible for immune down-regulation to repeated Ag challenge. We used intratracheal (IT) challenge of primed C57BL/6 mice with SRBC and on various days after single (1IT) or triple (3IT) challenge counted lung inflammatory cells and measured whole-lung cytokine mRNA and protein concentrations using RT-PCR and ELISA. We found that lung lymphocyte numbers and parenchymal lung inflammation decreased significantly at days 6 and 9 after final Ag challenge in 3IT mice compared with 1IT mice. Lungs of 3IT mice showed the following changes in relative mRNA expression: an earlier peak in IL-10, decreased IL-1beta, and a change from a Th2 response in 1IT mice to a Th1 response in 3IT mice (with pronounced increases in IL-12, IL-18, and IFN-gamma and decreased IL-4, IL-13, and IL-5). Similar types of changes were seen in whole-lung protein concentrations for TNF-alpha, IL-10, IL-12 p40, IFN-gamma, and IL-4. Additionally, mRNA expression of the endothelial selectins CD62E and CD62P decreased and lung lymphocyte apoptosis increased in the 3IT group. Thus, physiologic down-regulation of the pulmonary immune response to repeated Ag exposure is characterized by increased anti- and decreased proinflammatory cytokines that accompanies Th1 polarization. Similar mechanisms may act to minimize chronic lung inflammation in the majority of normal humans who do not develop progressive lung pathology when repeatedly exposed to inhaled or aspirated environmental Ags.     

Acute-phase cytokines IL-1β and TNF-α in brain development

The nervous and the immune systems share several molecules that control their development and function. We studied the temporal and spatial distribution of the immunoreactivity of two acute-phase cytokines, TNF-alpha and IL-1beta, in the developing sheep neocortex and compared it with the well-described distribution of fetuin, a fetal glycoprotein also known to modulate the production of cytokines by lipopolysaccharide (LPS)-stimulated monocytes and macrophages. TNF-alpha was present first at embryonic day 30 (E30) (term is 150 days in sheep) as a faint band of immunoreactivity between the ventricular zone and the primordial plexiform layer (preplate). IL-1beta was detected at the first appearance of the cortical plate (E35-E40). Both cytokines were present on both sides of the cortical plate, which contained fetuin-positive cells, but was free from cytokine staining. By E60, TNF-alpha immunoreactivity was less prominent than that of IL-1beta and was confined to the marginal zone and outer developing white matter; IL-1beta was present in the marginal zone and in two bands of immunoreactive cells, one at the border of the cortical plate/developing layer VI (cells of neuronal morphology) and the other at the border of layer V and the developing white matter (identified as microglia). By E80, TNF-alpha staining had disappeared and IL-1beta-immunopositive microglia were no longer detectable. By E100-E140 only a few immunoreactive cells were identified in layers V-VI; these did not co-localize with fetuin-positive cells. The differences in distribution between fetuin and the two cytokines suggest that the opsonizing role of fetuin, proposed for monocyte production of cytokines, is probably not present in the developing brain. However, early in neocortical development TNF-alpha and IL-1beta were present in the subplate zone at a time of intense synaptogenesis.     

Ganglioside GM1 effects on the expression of nerve growth factor (NGF), Trk-A receptor, proinflammatory cytokines and on autoimmune diabetes onset in non-obese diabetic (NOD) mice

NOD (non-obese diabetic) mice develop type 1 diabetes mellitus spontaneously and with a strong similarity to the human disease. Differentiation and function of pancreas beta cells are regulated by a variety of hormones and growth factors, including the nerve growth factor (NGF). Gangliosides have multiple immunomodulatory activities with immunosuppressive properties, decreasing lymphoproliferative responses and modulating cytokine production. In the present study, serum, pancreas islets and spleen mononuclear cells from NOD mice treated with monosialic ganglioside GM1 (100 mg/kg/day) and the group control which received saline solution were isolated to investigate the proinflammatory cytokines (IL-1beta, IFN-gamma, IL-12, TNF-alpha), NGF and its high-affinity receptor TrkA, peri-islet Schwann cells components (GFAP, S100-beta) expression and the relationship with diabetes onset and morphological aspects. Our results suggest that GM1 administration to female NOD mice beginning at the 4th week of life is able to reduce the index of inflammatory infiltrate and consequently the expression of diabetes, modulating the expression of proinflammatory cytokines (IL-12, IFN-gamma, TNF-alpha and IL-1beta). Furthermore, GM1 increases GFAP, S-100beta and NGF in pancreas islets, factors involved in beta cell survival.     

The effects of infection of thermal injury by Pseudomonas aeruginosa PAO1 on the murine cytokine response.

Pseudomonas aeruginosa infection, one of the major complications of burn wounds, may lead to sepsis and death. Using the Multi-Probe Template/RNase protection assay, we have compared the expression of different cytokine genes within the skin and livers of thermally injured mice infected with P. aeruginosa PAO1. Thermal injury alone enhanced or up-regulated certain cytokines, including macrophage colony-stimulating factor (M-CSF), interleukin 1 (IL-1)RI, IL-1 beta, macrophage inflammatory protein (MIP)-1 beta and MIP-2; while PAO1 challenge alone up-regulated tumour necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) expression. The combination of thermal injury plus PAO1 infection enhanced the expression of several pro-inflammatory and haematopoietic cytokines [stem cell factor (SCF), leukocyte inhibitory factor (LIF), IL-6 and TNF-alpha]; induced the expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) and G-CSF by 5 h and the expression of additional cytokines, including TGF-beta, TNF-beta, lymphotoxin beta (LT-beta), interferon gamma (IFN-gamma), and IFN-beta by 40 h post-burn/infection. While the most intense cytokine expression occurred in the skin, the majority of cytokines tested were also expressed in the liver by 40 h post-burn/infection. These results suggest that in P. aeruginosa infection of burn wounds: (1) up-regulation of the expression of different cytokines, locally and within the livers of burned mice, is an indication of P. aeruginosa -induced sepsis; and (2) IL-6 and G-CSF play an important role in the host response mechanism.     

The pro-inflammatory cytokines, IL-1beta and TNF-alpha, inhibit intestinal alkaline phosphatase gene expression

High levels of the pro-inflammatory cytokines, interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), are present in the gut mucosa of patients suffering form various diseases, most notably inflammatory bowel diseases (IBD). Since the inflammatory milieu can cause important alterations in epithelial cell function, we examined the cytokine effects on the expression of the enterocyte differentiation marker, intestinal alkaline phosphatase (IAP), a protein that detoxifies bacterial lipopolysaccharides (LPS) and limits fat absorption. Sodium butyrate (NaBu), a short-chain fatty acid and histone deacetylase (HDAC) inhibitor, was used to induce IAP expression in HT-29 cells and the cells were also treated +/- the cytokines. Northern blots confirmed IAP induction by NaBu, however, pretreatment (6 h) with either cytokine showed a dose-dependent inhibition of IAP expression. IAP Western analyses and alkaline phosphatase enzyme assays corroborated the Northern data and confirmed that the cytokines inhibit IAP induction. Transient transfections with a reporter plasmid carrying the human IAP promoter showed significant inhibition of NaBu-induced IAP gene activation by the cytokines (100 and 60% inhibition with IL-1beta and TNF-alpha, respectively). Western analyses showed that NaBu induced H4 and H3 histone acetylation, and pretreatment with IL-1beta or TNF-alpha did not change this global acetylation pattern. In contrast, chromatin immunoprecipitation showed that local histone acetylation of the IAP promoter region was specifically inhibited by either cytokine. We conclude that IL-1beta and TNF-alpha inhibit NaBu-induced IAP gene expression, likely by blocking the histone acetylation within its promoter. Cytokine-mediated IAP gene silencing may have important implications for gut epithelial function in the setting of intestinal inflammatory conditions.     

Oral administration of chitin down-regulates serum IgE levels and lung eosinophilia in the allergic mouse

Previous studies showed that local macrophages phagocytose nonantigenic chitin particles (1-10 micrometer polymers of N-acetyl-d -glucosamine) through mannose receptors and produce IL-12, IL-18, and TNF-alpha. These cytokines lead to the production of IFN-gamma by NK cells. To determine whether chitin could down-regulate Th2 responses, chitin was given orally (8 mg/day for 3 days before and 13 days during ragweed allergen immunization) in BALB/c and C57BL/6 mice. These ragweed-immunized mice were given ragweed intratracheally on day 11. Three days after the challenge, the immunized mice with saline (controls) showed increases in serum IgE levels and lung eosinophil numbers. The chitin treatment resulted in decreases of these events in both strains. To dissect the inhibitory mechanisms of Th2 responses, spleen cells (4 x 106 cells/ml) isolated from the ragweed-immunized mice (controls) were cultured in the presence of ragweed and/or chitin for 3 days (recall responses). Ragweed alone stimulated the production of IL-4 (0.6 ng/ml), IL-5 (20 U/ml), and IL-10 (3.2 ng/ml), but not IFN-gamma. Ragweed/chitin stimulation resulted in significant decreases of IL-4, IL-5, and IL-10 levels and the production of IFN-gamma (48 U/ml). Moreover, spleen cells isolated from the chitin-treated mice showed ragweed-stimulated IFN-gamma production (15 U/ml) and significantly lower levels of the Th2 cytokines, suggesting that the immune responses were redirected toward a Th1 response. Collectively, these results indicate that chitin-induced innate immune responses down-regulate Th2-facilitated IgE production and lung eosinophilia in the allergic mouse.     

Enhancing effect of IL-1, IL-17, and TNF-alpha on macrophage inflammatory protein-3alpha production in rheumatoid arthritis: regulation by soluble receptors and Th2 cytokines.

Macrophage inflammatory protein (MIP)-3alpha is a chemokine involved in the migration of T cells and immature dendritic cells. To study the contribution of proinflammatory cytokines and chemokines to the recruitment of these cells in rheumatoid arthritis (RA) synovium, we looked at the effects of the monocyte-derived cytokines IL-1beta and TNF-alpha and the T cell-derived cytokine IL-17 on MIP-3alpha production by RA synoviocytes. Addition of IL-1beta, IL-17, and TNF-alpha induced MIP-3alpha production in a dose-dependent manner. At optimal concentrations, IL-1beta (100 pg/ml) was much more potent than IL-17 (100 ng/ml) and TNF-alpha (100 ng/ml). When combined at lower concentrations, a synergistic effect was observed. Conversely, the anti-inflammatory cytokines IL-4 and IL-13 inhibited MIP-3alpha production by activated synoviocytes, but IL-10 had no effect. Synovium explants produced higher levels of MIP-3alpha in RA than osteoarthritis synovium. MIP-3alpha-producing cells were located in the lining layer and perivascular infiltrates in close association with CD1a immature dendritic cells. Addition of exogenous IL-17 or IL-1beta to synovium explants increased MIP-3alpha production. Conversely, specific soluble receptors for IL-1beta, IL-17, and TNF-alpha inhibited MIP-3alpha production to various degrees, but 95% inhibition was obtained only when the three receptors were combined. Similar optimal inhibition was also obtained with IL-4, but IL-13 and IL-10 were less active. These findings indicate that interactions between monocyte and Th1 cell-derived cytokines contribute to the recruitment of T cells and dendritic cells by enhancing the production of MIP-3alpha by synoviocytes. The inhibitory effect observed with cytokine-specific inhibitors and Th2 cytokines may have therapeutic applications.