Amelioration of experimental allergic neuritis by sodium fusidate (fusidin): suppression of IFN-gamma and TNF-alpha and enhancement of IL-10.

The immunomodulating antibiotic drug fusidic acid and its sodium salt sodium fusidate (fusidin) ameliorate several organ-specific immunoinflammatory diseases. Because preliminary observations suggest that fusidin may also exert a beneficial effect in Guillain-Barré syndrome (GBS), here we have studied the effects of fusidin on actively induced experimental autoimmune neuritis (EAN) in rats, a known animal model for GBS. Both prophylactic and therapeutic treatment with fusidin (4 mg/rat day ip) markedly ameliorated the clinical course of the disease compared to vehicle-treated animals. The beneficial effects were associated with profound modifications of the capacity of these rats to produce and release pro- and anti-inflammatory cytokines such as IFN-gamma, TNF-alpha and IL-10, which are important in regulating the development of EAN.     

Interleukin-12- and interferon-gamma-mediated natural killer cell activation by Agaricus blazei Murill

Dried fruiting bodies of Agaricus blazei Murill (A. blazei) and its extracts have generally used as complementary and alternative medicines (CAMs). Here, we report that the oral administration of A. blazei augmented cytotoxicity of natural killer (NK) cells in wild-type (WT) C57BL/6, C3H/HeJ, and BALB/c mice. Augmented cytotoxicity was demonstrated by purified NK cells from treated wild-type (WT) and RAG-2-deficient mice, but not from interferon-gamma (IFN-gamma) deficient mice. NK cell activation and IFN-gamma production was also observed in vitro when dendritic cell (DC)-rich splenocytes of WT mice were coincubation with an extract of A. blazei. Both parameters were largely inhibited by neutralizing anti-interleukin-12 (IL-12) monoclonal antibody (mAb) and completely inhibited when anti-IL-12 mAb and anti-IL-18 mAb were used in combination. An aqueous extract of the hemicellulase-digested compound of A. blazei particle; (ABPC) induced IFN-gamma production more effectively, and this was completely inhibited by anti-IL-12 mAb alone. NK cell cytotoxicty was augmented with the same extracts, again in an IL-12 and IFN-gamma-dependent manner. These results clearly demonstrated that A. blazei and ABPC augmented NK cell activation through IL-12-mediated IFN-gamma production.     

Essential pathogenic role of endogenous IL-18 in murine diabetes induced by multiple low doses of streptozotocin. Prevention of hyperglycemia and insulitis by a recombinant IL-18-binding protein: Fc construct

IL-18 is a cytokine structurally and functionally related to IL-1 that, in synergy with IL-12, stimulates the synthesis of IFN-gamma from T lymphocytes and natural killer cells. Because IFN-gamma plays a key pathogenic role in the development of murine immunoinflammatory diabetes induced by multiple low doses of streptozotocin (STZ) we investigated the effect of negating the actions of endogenous IL-18 in this model by administering recombinant IL-18-binding protein:Fc (IL-18 bp:Fc). C57BL/6 mice were injected once daily with 40 mg/kg STZ for 5 consecutive days, day 0 being the first day of STZ challenge. Relative to control animals treated in parallel with either PBS or human IgG, mice treated from day -3 to day 7 with daily doses of 150 microg of IL-18 bp:Fc exhibited lower incidence of diabetes and milder insulitis. In contrast, mice that were treated with IL-18 bp:Fc from day 7 to day 14 exhibited clinical and histological signs of STZ-induced diabetes similar to those of control mice treated with IgG. The protective effect of IL-18 bp:Fc was accompanied by modified ex vivo immune responses, in that spleen cells and peritoneal macrophages contained fewer IFN-gamma secreting cells and released lower amounts of nitrite (an index of nitric oxide production) and IL-1beta. We conclude that intact IL-18 function is essential for the full diabetogenic effect of low dose STZ in C57BL/6 mice.     

Up-regulation of granulomatous inflammation in interleukin-6 knockout mice infected with Rhodococcus aurantiacus

After intravenous injection of Rhodococcus aurantiacus normal mice develop non-necrotic granulomas, the formation of which is dependent on endogenous interferon-gamma (IFN-gamma). In the early phase of R. aurantiacus infection a high level of endogenous interleukin-6 (IL-6) is detected in the spleen extracts, though its importance is unknown. Using IL-6 knockout (IL-6-/-) mice, we studied the role of IL-6 in granulomatous inflammation induced by R. aurantiacus. The size of granulomas generated in IL-6-/- mice was significantly larger than that of wild-type (IL-6+/+) mice at 2 weeks postinjection (p.i). Moreover, central necrosis of the granuloma was observed in IL-6-/- mice but not in IL-6+/+ controls. Titres of endogenous IFN-gamma and tumour necrosis factor-alpha (TNF-alpha) were markedly increased in the spleens and livers of IL-6-/- mice in comparison with IL-6+/+ mice at days 1 through 3 p.i. In vivo administration of either an anti-IFN-gamma monoclonal antibody (mAb) or anti-TNF-alpha mAb to IL-6-/- mice reduced the number and size of granulomas, and prevented formation of necrotic granulomas. In addition, the production of endogenous IFN-gamma and TNF-alpha in the early phase of R. aurantiacus infection by IL-6-/- mice was suppressed by treatment with recombinant IL-6 (rIL-6). This suppression of IFN-gamma and TNF-alpha production was followed by a reduction in the number and size of central necrotic granulomas at 2 weeks p.i. These findings suggest that overproduction of IFN-gamma and TNF-alpha induces central necrotic granuloma formation in IL-6-/- mice, and that IL-6 down-regulates granulomatous inflammation reaction in response to R. aurantiacus infection by modulating production of IFN-gamma and TNF-alpha.     

Neutrophil depletion exacerbates experimental Chagas' disease in BALB/c, but protects C57BL/6 mice through modulating the Th1/Th2 dichotomy in different directions

To elucidate the roles of neutrophils in experimental Chagas' disease, we depleted the peripheral neutrophils in BALB/c and C57BL/6 mice with a monoclonal antibody 1 day before Trypanosoma cruzi infection. Neutrophil depletion in BALB/ c mice resulted in exacerbation of the disease and decreased expression of mRNA for Th1 cytokines, including IL-2 and IFN-gamma, IL-12p40 and TNF-alpha in their spleens after the infection, while a Th2 cytokine, IL-10, increased especially 1 day after infection. Neutrophils from infected BALB / c mice expressed mRNA for IL-12p40, IFN-gamma, TNF-alpha and Th1 chemoattractive chemokines, monokine induced by IFN-gamma (MIG) and macrophage inflammatory protein-1alpha (MIP-1alpha ). In contrast, in C57BL/6 mice neutrophil depletion induced resistance to the disease and enhanced the expression of the above Th1 cytokines, although IL-10 mRNA in neutrophil-depleted C57BL/6 mice was also higher than in control mice. Neutrophils from C57BL/6 mice did not express IL-12p40, IFN-gamma and MIG but expressed TNF-alpha, MIP-1alpha and IL-10. Therefore, neutrophils may play opposite roles in these two strains of mice with respect to protection versus exacerbation of T. cruzi infection, possibly through modulating the Th1/Th2 dichotomy in different directions.     

Analysis of the activation profile of dendritic cells derived from the bone marrow of interleukin-12/interleukin-23-deficient mice

We have previously shown that macrophages from interleukin (IL)-12p40 gene knockout (IL-12/IL-23-/-) mice have a bias towards the M2 activation profile, spontaneously secreting large quantities of transforming growth factor-beta1 (TGF-beta1) and producing low levels of nitric oxide (NO) in response to lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). To verify whether the activation profile of dendritic cells (DCs) is also influenced by the absence of IL-12/IL-23, bone marrow-derived DCs from IL-12/IL-23-/- and C57BL/6 mice were evaluated. At first we noticed that approximately 50% of the C57BL/6 DCs were dead after LPS-induced maturation, whereas the mortality of IL-12/IL-23-/- DCs was < 10%, a protective effect that diminished when recombinant IL-12 (rIL-12) was added during maturation. Similarly to macrophages, mature IL-12/IL-23-/- DCs (mDCs) produced higher levels of TGF-beta1 and lower levels of NO than C57BL/6 mDCs. NO release was IFN-gamma-dependent, as evidenced by the poor response of IFN-gamma-/- and IL-12/IL-23-/-IFN-gamma-/- mDCs. Nevertheless, IFN-gamma deficiency was not the sole reason for the weak NO response observed in the absence of IL-12/IL-23. The high level of TGF-beta1 secretion by IL-12/IL-23-/- mDCs could explain why exogenous IFN-gamma partially restored the NO production of IFN-gamma-/- mDCs, while IL-12/IL-23-/- IFN-gamma-/- mDCs remained unresponsive. We also showed that CD4+ T-cell proliferation was inhibited by C57BL/6 mDCs, but not by IL-12/IL-23-/- mDCs. IFN-gamma and NO appear to mediate this antiproliferative effect because this effect was not observed in the presence of mDCs from IFN-gamma-/- or IL-12/IL-23-/- IFN-gamma-/- mice and it was attenuated by aminoguanidine. We conclude that the presence of IL-12/IL-23 during LPS-induced maturation influences the activation profile of DCs by a mechanism that is, only in part, IFN-gamma dependent.     

Reciprocal immunomodulatory effects of gamma interferon and interleukin-4 on filaria-induced airway hyperresponsiveness

Tropical pulmonary eosinophilia (TPE) is a severe asthmatic syndrome of lymphatic filariasis, in which an allergic response is induced to microfilariae (Mf) in the lungs. Previously, in a murine model for TPE, we have demonstrated that recombinant interleukin-12 (IL-12) suppresses pulmonary eosinophilia and airway hyperresponsiveness (AHR) by modulating the T helper (Th) response in the lungs from Th2- to Th1-like, with elevated gamma-interferon (IFN-gamma) production and decreased IL-4 and IL-5 production. The present study examined the immunomodulatory roles of IL-4 and IFN-gamma in filaria-induced AHR and pulmonary inflammation using mice genetically deficient in these cytokines. C57BL/6, IL-4 gene knockout (IL-4(-/-)), and IFN-gamma(-/-) mice were first immunized with soluble Brugia malayi antigens and then inoculated intravenously with 200,000 live Mf. Compared with C57BL/6 mice, IL-4(-/-) mice exhibited significantly reduced AHR, whereas IFN-gamma(-/-) mice had increased AHR. Histopathologically, each mouse strain showed increased cellular infiltration into the lung parenchyma and bronchoalveolar space compared with na?ve animals. However, consistent with changes in AHR, IL-4(-/-) mice had less inflammation than C57BL/6 mice, whereas IFN-gamma(-/-) mice had exacerbated pulmonary inflammation with the loss of pulmonary architecture. Systemically, IL-4(-/-) mice produced significantly higher IFN-gamma levels compared with C57BL/6 mice, whereas IFN-gamma(-/-) mice produced significantly higher IL-4 levels. These data indicate that IL-4 is required for the induction of filaria-induced AHR, whereas IFN-gamma suppresses AHR.     

Effects of interleukin-4 deprivation and treatment on resistance to Trypanosoma cruzi

Trypanosoma cruzi (Y strain)-infected interleukin-4(-/-) (IL-4(-/-)) mice of strains 129/J, BALB/c, and C57BL/6 showed no significant difference in parasitemia levels or end point mortality rates compared to wild-type (WT) mice. Higher production of gamma interferon (IFN-gamma) by parasite antigen (Ag)-stimulated splenocytes was observed only for C57BL/6 IL-4(-/-) mice. Treatment of 129/J WT mice with recombinant IL-4 (rIL-4), rIL-10, anti-IL-4, and/or anti-IL-10 monoclonal antibodies (MAbs) did not modify parasitism. However, WT mice treated with rIL-4 and rIL-10 had markedly increased parasitism and suppressed IFN-gamma synthesis by spleen cells stimulated with parasite Ag, concanavalin A, or anti-CD3. Addition of anti-IL-4 MAbs to splenocyte cultures from infected WT 129/J, BALB/c, or C57BL/6 mice failed to modify IFN-gamma synthesis levels; in contrast, IL-10 neutralization increased IFN-gamma production and addition of rIL-4 and/or rIL-10 diminished IFN-gamma synthesis. We conclude that endogenous IL-4 is not a major determinant of susceptibility to Y strain T. cruzi infection but that IL-4 can, in association with IL-10, modulate IFN-gamma production and resistance.     

Role of TNF and IL-1 in infections with Toxoplasma gondii.

Mice lethally infected with the C56 strain of Toxoplasma gondii and treated with purified recombinant murine tumour necrosis factor (TNF, 1 microgram/day/mouse for 8 days), recombinant human interleukin-1 (IL-1 alpha or IL-1 beta, 100 ng/day/mouse for 5 days) or a single dose of a combination of TNF (1 microgram/mouse) and IL-1 alpha or IL-1 beta (100 ng/mouse) were significantly protected against death (P less than 0.05-0.001, as compared with untreated infected controls). Mice infected with 100,000 tachyzoites of the highly virulent RH strain of T. gondii released serum TNF in relation to the time after infection and were primed to secrete an enhanced level of serum TNF upon stimulation with bacterial lipopolysaccharide (LPS). In vitro studies showed that interferon-gamma (IFN-gamma) increased the antimicrobial activity of murine peritoneal macrophages whereas TNF, IL-1 alpha and IL-1 beta did not. TNF, however, synergized with the anti-toxoplasmic effect provided by IFN-gamma and this activity was blocked by anti-TNF antibodies. IFN-gamma induced the production of TNF and the anti-toxoplasmic effect provided by IFN-gamma seemed to be dependent partly on the production of TNF. We conclude that TNF and IL-1 may play a significant role in modulating the host's immune defence against T. gondii infection.     

Requirement for both IL-12 and IFN-gamma signaling pathways in optimal IFN-gamma production by human T cells

Phytohemagglutinin (PHA)-derived T lymphoblasts or T cell clones from patients genetically deficient in IL-12R beta 1 (IL-12R beta 1(-/-)) or IFN-gamma R1 (IFN-gamma R1(-/-)) produced two- to threefold reduced IFN-gamma levels compared to the corresponding cells from healthy individuals after anti-CD3 and PMA stimulation. Moderate IFN-gamma production was observed in PHA-derived T lymphoblasts or T cell clones derived from healthy subjects in the presence of anti-IFN-gamma R1 or anti-IL-12 mAb, whereas it was negligible in the presence of both mAb. However, when anti-IFN-gamma R1 and/or anti-IL-12 mAb were added during restimulation, the cells produced normal levels of IFN-gamma, indicating that both IFN-gamma and IL-12 had an effect on the priming phase. Moderate production of IFN-gamma was partially enhanced only in IFN-gamma R1(-/-) T cell clones generated in the presence of IL-12, but was almost completely abolished when IL-12R beta 1(-/-) and IFN-gamma R1(-/-) T cell clones were generated in the presence of anti-IFN-gamma R1 or anti-IL-12 mAb, respectively. IL-4 production was enhanced in T cell clones from IL-12R beta 1(-/-),but not from IFN-gamma R1(-/-) patients, whereas IL-10 and IL-2 production did not differ significantly in polyclonal T cells or clones from healthy and deficient individuals. These results indicate that IL-12R beta 1- and IFN-gamma R1-dependent signals co-ordinately regulate IFN-gamma, but not IL-2 and IL-10 production, whereas only IL-12 negatively controls IL-4 production by in vitro-generated T cell clones. Thus, although IL-12 and IFN-gamma signals are each sufficient for moderate production of IFN-gamma by human T cells, both are needed for optimal IFN-gamma production, and in the absence of both IFN-gamma production is completely abrogated.     

HIV-1 induces IL-10 production in human monocytes via a CD4-independent pathway

In HIV-infected patients, increased levels of IL-10, mainly produced by virally infected monocytes, were reported to be associated with impaired cell-mediated immune responses. In this study, we investigated how HIV-1 induces IL-10 production in human monocytes. We found that CD14(+) monocytes infected by either HIV-1(213) (X4) or HIV-1(BaL) (R5) produced IL-10, IL-6, tumor necrosis factor-alpha (TNF-alpha), and to a lesser extent, IFN-gamma. However, the capacity of HIV-1 to induce these cytokines was not dependent on virus replication since UV-inactivated HIV-1 induced similar levels of these cytokines. In addition, soluble HIV-1 gp160 could induce CD14(+) monocytes to produce IL-10 but at lower levels. Cross-linking CD4 molecules (XLCD4) with anti-CD4 mAbs and goat anti-mouse IgG (GAM) resulted in high levels of IL-6, TNF-alpha and IFN-gamma but no IL-10 production by CD14(+) monocytes. Interestingly, neither anti-CD4 mAbs nor recombinant soluble CD4 (sCD4) receptor could block IL-10 secretion induced by HIV-1(213), HIV-1(BaL) or HIV-1 gp160 in CD14(+) monocytes, whereas anti-CD4 mAb or sCD4 almost completely blocked the secretion of the other cytokines. Furthermore, HIV-1(213) could induce IL-10 mRNA expression in CD14(+) monocytes while XLCD4 by anti-CD4 mAb and GAM failed to do so. As with IL-10 protein levels, HIV-1(213)-induced IL-10 mRNA expression in CD14(+) monocytes could not be inhibited by anti-CD4 mAb or sCD4. Taken together, HIV-1 binding to CD14(+) monocytes can induce CD4-independent IL-10 production at both mRNA and protein levels. This finding suggests that HIV induces the immunosuppressive IL-10 production in monocytes and is not dependent on CD4 molecules and that interference with HIV entry through CD4 molecules may have no impact on counteracting the effects of IL-10 during HIV infection.     

In vivo administration of IL-18 can induce IgE production through Th2 cytokine induction and up-regulation of CD40 ligand (CD154) expression on CD4+ T cells

IL-18 is considered to be a strong cofactor for CD4+ T helper 1 (Th1) cell induction. We have recently reported that IL-18 can induce IL-13 production in both NK cells and T cells in synergy with IL-2 but not IL-12, suggesting IL-18 can induce Th1 and Th2 cytokines when accompanied by the appropriate first signals for T cells. We have now found that IL-18 can act as a cofactor to induce IL-4, IL-10 and IL-13 as well as IFN-gamma production in T cells in the presence of anti-CD3 monoclonal antibodies (mAb). IL-18 can rapidly induce CD40 ligand (CD154) mRNA and surface expression on CD4+ but not CD8+ T cells. The administration of IL-18 alone in vivo significantly increased serum IgE levels in C57BL/6 (B6) and B6 IL-4 knockout mice. Furthermore, the administration of IL-18 plus IL-2 induced approximately 70-fold and 10-fold higher serum levels of IgE and IgG1 than seen in control B6 mice, respectively. IgE and IgG1 induction in B6 mice by administration of IL-18 plus IL-2 was eliminated by the pretreatment of mice with anti-CD4 or anti-CD154, but not anti-CD8 or anti-NK1.1 mAb. These results suggest that IL-18 can induce Th2 cytokines and CD154 expression, and can contribute to CD4+ T cell-dependent, IL-4-independent IgE production.     

Granulocyte-macrophage colony-stimulating factor (GM-CSF) regulates cytokine induction by 1,3-beta-D-glucan SCG in DBA/2 mice in vitro.

Sparassis crispa Fr. is an edible/medicinal mushroom that recently became cultivable in Japan. SCG is a major 6-branched 1,3-beta-D-glucan in S. crispa showing antitumor activity. We recently found that the splenocytes from naive DBA/1 and DBA/2 mice strongly react with SCG to produce interferon-gamma (IFN-gamma). In this study, cytokines induced by SCG were screened and found to be IFN-gamma, tumor necrosis factor-alpha (TNF-alpha), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-12 (IL-12p70). The addition of recombinant murine GM-CSF (rMuGM-CSF) to spleen cell cultures from various strains of mice synergistically enhanced IFN-gamma, TNF-alpha and IL-12p70 in the presence of SCG. In contrast, neutralizing GM-CSF using anti-GM-CSF monoclonal antibody (mAb) significantly inhibited IFN-gamma, TNF-alpha, and IL-12p70 elicited by SCG. We conclude that GM-CSF is a key molecule for cytokine induction by beta-glucan, and GM-CSF induction by SCG is the specific step in DBA/2 mice in vitro.     

Nonspecific stimulation of host defense by Corynebacterium kutscheri. III. Enhanced cytokine induction by the active moiety of C. kutscheri.

The present study was carried out to ascertain whether the active component of Corynebacterium kutscheri (CK-M) could stimulate host cells of mice to produce several cytokines. CK-M stimulated thioglycollate-induced peritoneal macrophages to produce interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) at concentrations of 1-100 ng/ml, and it also induced IL-2 and interferon-gamma (IFN-gamma) as well as IL-6 production by splenocytes. Maximum production of each cytokine induced by CK-M was obtained at the following doses: IL-1 at 5 ng/ml, TNF-alpha at 50 ng/ml, IL-2 at 1 microgram/ml, IL-6 at 500 ng/ml and IFN-gamma at 750 ng/ml. In contrast, IL-4 was not produced to a significant extent by CK-M-stimulated splenocytes. Furthermore, when mice were intravenously injected with 20 micrograms of CK-M, IL-2 and IFN-gamma production by splenocytes, upon stimulation with either formalin-killed C. kutscheri or mitogens, was significantly higher on day 10 of treatment than on day 2. Additionally, the cytotoxicity to L929 cells of this serum from CK-M-treated mice increased with time, and the activity in the serum of day 10 was not abrogated by the antibody to TNF-alpha. Data obtained here indicate that CK-M may preferentially stimulate type-1 helper T cells to produce IL-2 and IFN-gamma, and that the enhanced cytokine production could contribute to the nonspecific resistance induced by C. kutscheri.     

多房棘球绦虫混合重组BCG-EmⅡ/3和BCG-Em14-3-3疫苗诱导小鼠脾细胞因子的变化

目的：探讨多房棘球绦虫混合重组BCG—EmII／3和BCG—Eml4—3—3疫苗免疫后再以Em原头节攻击后小鼠脾细胞因子的变化。方法：将疫苗采用皮下注射和鼻腔内接种分别免疫BALB／c小鼠后8周，用多房棘球绦虫原头节进行攻击感染。感染后18周杀鼠取脾，分离脾细胞，用EmAg或ConA刺激培养，并收集脾细胞培养上清液，用试剂盒检测脾细胞培养上清液中IL-2、IFN—γ、TNF—α和IL-4的水平，同时设有空载体、BCG和PBS对照。结果-疫苗接种组的IFN—γ和TNF—α水平升高，IL-4水平降低；皮下注射组的TNF—α水平高于鼻腔内接种组。结论-多房棘球绦虫混合重组BCG—EmⅡ／3和BCG—Eml4—3—3疫苗可诱导小鼠产生Th1型细胞应答，抵抗Em原头节的攻击感染。疫苗皮下注射途径优于鼻腔内接种。     

Effect of IL-4 and interferon-gamma (IFN-gamma) on IL-3- and IL-5-induced eosinophil differentiation from human cord blood mononuclear cells.

IL-4 and IFN-gamma positively and negatively regulate allergic inflammation. To determine the regulatory mechanisms of eosinopoiesis by cytokines, we examined the effect of recombinant IL-4 and IFN-gamma and of anti-IL-4 and anti-IFN-gamma antibodies on IL-3- and IL-5-induced eosinophil differentiation from human umbilical cord blood mononuclear cells. rhIL-4 (10-300 U/ml) inhibited IL-3- and IL-5-induced eosinophil differentiation from cord blood mononuclear cells on day 28 of culture by 62-81% in a concentration-dependent manner. rhIFN-gamma (5-500 U/ml) also inhibited IL-3- and IL-5-induced eosinophil differentiation by 80-99% in a concentration-dependent manner. The inhibitory effect of rhIL-4 and rhIFN-gamma was observed only when rhIL-4 or rhIFN-gamma were present in the culture from day 0 to day 14, but not from day 15 to day 28. Addition of anti-IL-4 antibody to the culture enhanced IL-3- and IL-5-induced eosinophil differentiation on day 28 of culture by 30%, whereas anti-IL-2 MoAb and anti-IFN-gamma MoAb had no significant effect. These results indicate that IL-4 and IFN-gamma have inhibitory effects on IL-3- and IL-5-induced eosinophil differentiation from its progenitor cells.     

Failure of exogenously administered interferon-gamma or blockage of endogenous interleukin-4 with specific inhibitors to augment the incidence of autoimmune diabetes in male NOD mice.

Interferon (IFN)-gamma and interleukin (IL)-4 are prototypic type 1 and type 2 cytokines which are known to play pathogenetic and protective roles, respectively, in NOD mouse IDDM. The capacity of male NOD mice to produce more IL-4 and less IFN-gamma within the insulitic lesions than females has been suggested to contribute to their lower incidence of diabetes. In this study we have tested the effects of prolonged prophylactic treatment of male NOD mice with rat IFN-gamma, mouse IFN-gamma, anti-IL-4 monoclonal antibody (mAb) and recombinant murine soluble IL-4 receptor (smIL-4R) on the diabetogenic events leading to insulitis and diabetes. None of these treatments influenced spontaneous and/or cyclophosphamide-induced autoimmune diabetogenesis in male NOD mice. Control mice exhibited comparable histological signs of insulitis and incidence of diabetes to those treated with either mouse/rat IFN-gamma or specific IL-4 inhibitors. On the contrary, both clinical and histological signs of diabetes were suppressed by prophylactic treatment with anti-IFN-gamma mAb. These findings indicate that the autoimmune diathesis of male NOD mice towards IDDM cannot be augmented by manipulation of endogenous IFN-gamma or IL-4.     

Disruption of interleukin-27 signaling results in impaired gamma interferon production but does not significantly affect immunopathology in murine schistosome infection

In schistosomiasis mansoni, parasite eggs cause hepatointestinal granulomatous inflammation and fibrosis mediated by CD4 T cells specific for egg antigens. The severity of disease varies extensively in humans and among mouse strains. Marked disease exacerbation induced in typically low-pathology C57BL/6 mice by immunization with schistosome egg antigens (SEA) in complete Freund's adjuvant (SEA/CFA) correlates with elevated production of the proinflammatory cytokines gamma interferon (IFN-gamma) and interleukin-17 (IL-17), which are regulated by IL-12 and IL-23, respectively. Here we examined the effect on the schistosome infection of a third member of the IL-12 family of heterodimeric cytokines, IL-27, using SEA/CFA-immunized and unimmunized mice deficient in the IL-27 receptor chain WSX-1 (WSX-1(-/-)). SEA-stimulated bulk mesenteric lymph node cells or CD4 T cells from 7-week-infected WSX-1(-/-) mice produced significantly less IFN-gamma than did those from C57BL/6 mice, even though there was no difference between these mice in exacerbated hepatic egg-induced granulomatous inflammation or in the levels of IL-17 induced by immunization with SEA/CFA. A fraction of the cells in the granulomas stained positive for IL-27, but there were no significant differences between WSX-1(-/-) and BL/6 mice, nor were there differences in the number of CD4 T cells and eosinophils. A 24-week chronic infection resulted in markedly reduced levels of proinflammatory cytokines, including IFN-gamma, in WSX-1(-/-) mice, but again the magnitude of immunopathology was not significantly different between the two groups. These findings indicate that despite the impaired IFN-gamma production, IL-27 signaling has no significant effect on either the magnitude of egg-induced immunopathology or on its closest in vitro correlate, IL-17.     

Dexamethasone promotes type 2 cytokine production primarily through inhibition of type 1 cytokines.

Glucocorticoids, at concentrations mimicking stress-physiologic plasma levels, cause an in vitro shift in the type 1/type 2 cytokine balance of human peripheral blood mononuclear cells (PBMC) toward a predominant type 2 response. The mechanisms of these immune alterations are currently unknown but may involve modulation of key cytokines known to regulate the type 1/type 2 cytokine balance. Therefore, we sought to determine the role of cytokines previously reported to regulate the type 1/type 2 cytokine balance, including interleukin-12 (IL-12), interferon-gamma (IFN-gamma, IL-10, IL-4, and IL-13, in the glucocorticoid-mediated human type 1/type 2 cytokine alterations. Human PBMC were stimulated in vitro with tetanus toxoid in the presence of 10(-8) M dexamethasone (DEX). Cultures were supplemented with recombinant human (rHuIL-12), rHuIFN-gamma, or neutralizing monoclonal antibodies (mAb) against IL-4, IL-10, or IL-13. DEX decreased IFN-gamma production and increased IL-4 and IL-10 production by tetanus-stimulated PBMC. The addition of either recombinant IL-12p70 or IFN-gamma abrogated the DEX-mediated decrease in IFN-gamma and increase in IL-4 production. Neutralization of IL-4 activity partially abrogated the DEX-induced alterations in IFN-gamma and IL-4, but not IL-10, production. Neutralization of IL-10 or IL-13 had no effect on the Dex-mediated type 1/type 2 cytokine alterations. Therefore, the DEX-mediated type 1/type 2 cytokine alterations in tetanus-stimulated PBMC are primarily the result of downregulation of type 1 cytokines, subsequently permitting the production of type 2 cytokines.     

CpG oligodeoxynucleotides do not require TH1 cytokines to prevent eosinophilic airway inflammation in a murine model of asthma

BACKGROUND: Oligodeoxynucleotides (ODNs) containing the dinucleotide CpG in a specific sequence context (CpG-ODNs) have the ability to prevent the development of eosinophilic airway inflammation and bronchial hyperreactivity in a murine model of asthma. We have previously demonstrated that CpG-ODNs stimulate expression of the T(H1)-inducing cytokines IFN-gamma and IL-12 in a murine model of asthma and that this stimulation is associated with the protection against asthmatic inflammation. OBJECTIVE: The purpose of this study was to examine whether the protection conferred by CpG-ODNs in a schistosome egg-egg antigen murine model of asthma is dependent on the induction of IFN-gamma, IL-12, or both. METHODS: C57BL/6 mice were sensitized to schistosome eggs in the presence or absence of CpG-ODNs or control ODNs and then stimulated with soluble egg antigen in the airway. The protection offered by CpG-ODNs in these mice was compared with the protection induced by CpG-ODNs in IL-12 and IFN-gamma knockout mice and in mice treated with anticytokine blocking antibodies. Double-knockout mice (IL-12/IFN-gamma) were also generated and used in these studies. Determinations included airway eosinophilic inflammation and bronchial hyperreactivity to inhaled methacholine. RESULTS: We found that CpG-ODNs confer protection against both airway eosinophilia and bronchial hyperreactivity in the absence of IFN-gamma or IL-12 or in the presence of both cytokines together. However, in the absence of either IL-12 or IFN-gamma, mice require 10 times as much CpG-ODNs to be protected against the induction of airway eosinophilia. The T(H2) cytokines IL-4 and IL-5 were reduced in all of the CpG-treated mice, although less in the absence of IL-12 and IFN-gamma. CONCLUSION: These data indicate that CpG-ODNs prevent the generation of T(H2)-like immune responses by multiple mechanisms, which involve, but do not require, IL-12 and IFN-gamma. A direct suppressive effect of CpG-ODNs on T(H2) responses is suggested by their reduction in IFN-gamma and IL-12 knockout mice.