卡介苗(BCG)通过诱导IL-12产生和受体表达促进人NK细胞功能

目的:研究卡介苗(BCG)对人自然杀伤细胞(NK)功能的作用及其机制.方法:分离抗结核抗体阴性志愿者外周血PBMC、纯化NK细胞, 分别与BCG、 IL-12、 BCG+IL-12、 BCG+抗IL-12Rβ1 mAb(2B10)培养.利用ELISA方法检测培养上清液IFN-γ、 IL-12p40含量;利用ELISpot方法检测IFN-γ、颗粒酶B产生细胞的频率;利用四甲基偶氮唑盐(MTT)比色法测定杀伤功能.利用流式细胞术检测NK细胞IL-12Rβ1的表达.结果:BCG呈剂量依赖的方式诱导PBMC产生IFN-γ.在BCG刺激条件下, PBMC颗粒酶B分泌细胞数明显高于不加任何刺激剂组(P<0.05).BCG增强PBMC杀伤活性.BCG不能诱导纯化NK细胞产生IFN-γ, 但与IL-12同时刺激则表现出协同作用.纯化NK细胞经BCG刺激后杀伤活性与未刺激相比差异无统计学意义.BCG呈剂量依赖方式诱导PBMC产生IL-12、并促进NK细胞不同亚群表达IL-12Rβ1.2B10抗体抑制BCG对PBMC产生IFN-γ和分泌颗粒酶B的诱导作用.结论:BCG间接地促进NK细胞的生物学活性, 其部分机制是通过诱导单核细胞产生内源性IL-12、并上调NK细胞表达IL-12R.     

Oral cow milk challenge abolishes antigen-specific interferon-γ production in the peripheral blood of children with atopic dermatitis and cow milk allergy

Background A major feature of atopic dermatitis (AD) is the propensity to generate IgE to environmental antigens. Despite extensive information on IgE dysregulation in AD, the nature of immune responses to ingested allergens is poorly characterized. Objective To determine the clinical and immunological responses to food in AD patients. Methods To characterize the type and timing of clinical reactions to oral cow milk, 83 AD patients aged 2 to 60 months were subjected to double-blind placebo-controlled food challenge (DBPCFC). IFN-γ and IL-4 production by their peripheral blood mononuclear cells (PBMC) was determined before and after DBPCFC. Results Of 50 patients positive to DBPCFC, 46% manifested exanthematous-type immediate-onset reactions and 54% eczematous-type late-onset reactions. In either group, the production of lL-4 and IFN-γ by Concanavalin A-stimulated FBMC was comparable before and after DBPCFC. For immediate-reacting patients, the median IFN-γ production by milk-stimulated PBMC was 11.5 (4.2–17.2) pg/mL as against 2.3 (0.2–5.7) pg/mL by unstimulated PBMC, P = 0.0008 before DBPCFC, and 4.6 (2.8–10.3) pg/mL vs 4.2 (1.7–9.0) pg/mL, P = 0.40, correspondingly after DBPCFC. Conclusion Before DBPCFC, immediate-reacting but not late-reacting patients were found to be capable of allergen-specific IFN-γ production in vitro, indicating the heterogeneity in AD patients. After DBPCFC, the IFN-γ generation abolished, indicating the effect of oral allergen exposure on IFN-γ-producing responses of AD patients.     

Immunological markers indicating the effectiveness of pharmacological treatment in human hydatid disease

The relation of interferon-gamma (IFN-γ), IL-4, IL-10 production and specific IgE, total IgG, IgG subclass expression to the effectiveness of pharmacological treatment in human hydatid disease (Echinococcus granulosus infection) was evaluated in 27 hydatid patients divided into four clinical groups according to their response to albendazole/mebendazole therapy (full, partial, low and non-responders). After parasite antigen stimulation, peripheral blood mononuclear cells (PBMC) from full responders produced significantly more IFN-γ (P= 0·038), significantly less IL-4 (P= 0·001) and less IL-10 than PBMC from non-responders. PBMC from partial and low responders produced intermediate cytokine concentrations. ELISA determining immunoglobulin production showed that sera from all non-responders had IgE and IgG4 antibodies, both regulated by IL-4. In contrast to IgG4, IgE decreased rapidly in full responders. Full responders also showed the highest percentage of IgG3 reactions. Qualitative analysis of total IgG responses in hydatid patients’ sera determined by immunoblotting showed that binding profiles to hydatid cyst fluid antigen differed in the four groups of treated patients. Non-responders had the highest percentage of reactions to all subunits of antigens 5 and B, and full responders had the highest percentage of reactions to antigen 5 alone. The high IFN-γ production associated with a lack of IL-4 and low IL-10 production in the full responders, and vice versa the high IL-4 and IL-10 production associated with lack of or low IFN-γ production in the non-responders implies Th1 cell activation in protective immunity and Th2 cell activation in susceptibility to hydatid disease. IgE may be a useful marker of therapeutic success in hydatid patients with pretreatment specific IgE antibodies. IgG subclass responses and differential immunoglobulin subclass binding pattern to hydatid antigens may also be useful in the immunosurveillance of hydatid disease.     

Interleukin-10 controls interferon-γ and tumor necrosis factor production during experimental endotoxemia

Interleukin-10 (IL-10) is a potent inhibitor of lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) production and has been shown to protect mice from endotoxin shock. As IFN-γ is another important mediator of LPS toxicity, we studied the effects of IL-10 on LPS-induced IFN-γ synthesis in vitro and in vivo. First, we found that the addition of recombinant human IL-10 (rhIL-10) (10 U/ml) to human whole blood markedly suppressed LPS-induced IFN-γ release while neutralization of endogenously synthesized IL-10 resulted in increased IFN-γ levels. The ability of rIL-10 to inhibit LPS-induced IFN-γ synthesis was also observed in vivo in mice. Indeed, administration of 1000 U recombinant mouse IL-10 (rmIL-10) 30 min before and 3 h after challenge of BALB/c mice with 100 μg LPS resulted in a threefold decrease in peak IFN-γ serum levels. We then examined the production and the role of IL-10 during murine endotoxemia. We found that LPS injection causes the rapid release of IL-10, peak IL-10 serum levels being observed 90 min after LPS challenge. Neutralization of endogenously produced IL-10 by administration of 2 mg JES5-2A5 anti-IL-10 monoclonal antibody (mAb) 2h before LPS challenge resulted in a marked increase in both TNF and IFN-γ serum levels while irrelevant isotype-matched mAb had no effect. The enhanced production of inflammatory cytokines in anti-IL-10 mAb-treated mice was associated with a 60% lethality after injection of 500 μg LPS, while all mice pretreated with control mAb survived. We conclude that the rapid release of IL-10 during endotoxemia is a natural antiinflammatory response controlling cytokine production and LPS toxicity.     

Interferon-γ-inducing factor enhances T helper 1 cytokine production by stimulated human T cells: synergism with interleukin-12 for interferon-γ production

The novel cytokine interferon-γ-inducing factor (IGIF) augments natural killer (NK) cell activity in cultures of human peripheral blood mononuclear cells (PBMC), similarly to the structurally unrelated cytokine interleukin (IL)-12. IGIF has been found to enhance the production of interferon-γ (IFN-γ) and granulocyte/macrophage colony-stimulating factor (GM-CSF) while inhibiting the production of IL-10 in concanavalin A (Con A)-stimulated PBMC. In this study, when anti-CD3 monoclonal antibody (mAb)-stimulated human enriched T cells were exposed to IGIF, the cytokine dose-dependently enhanced the proliferation of the cells and this could be completely inhibited by a neutralizing antibody against IL-2 at lower concentrations of IGIF. Neutralizing antibody against IFN-γ had only insignificant inhibitory effects on T cell proliferation at higher concentrations of IGIF. Enzyme-linked immunosorbent assays (ELISA) revealed that, like PBMC, T cells exposed to IGIF produced large amounts of IFN-γ; however, changes in the production of IL-4 and IL-10 were minimal. IGIF, but not IL-12, significantly enhanced IL-2 and GM-CSF production in T cell cultures, as determined by CTLL-2 bioassay and ELISA, respectively; however, both IGIF and IL-12 enhanced IFN-γ production by the T cells. When T cells were exposed to a combination of IGIF and IL-12, a synergistic effect was observed on the production of IFN-γ, but not on production of IL-2 and GM-CSF. In conclusion, IGIF enhances T cell proliferation apparently through an IL-2-dependent pathway and enhances Th1 cytokine production in vitro and exhibits synergism when combined with IL-12 in terms of enhanced IFN-γ production but not IL-2 and GM-CSF production. Based on structural and functional differences from any known cytokines, it was recently proposed that this cytokine be designated interleukin-18.     

Bacterial extract (OM-89) specific and non specific immunomodulation in rheumatoid arthritis patients

The Escherichia Coli bacterial extract (OM-89) is used in the treatment of rheumatoid arthritis (RA). We evaluated the immunological changes induced by oral administration of OM-89 in 12 RA patients (polyclonal T cell reactivity to PHA, T cell precursor frequencies specific for OM-89 and Tetanus toxoid (TT), a control antigen and the release of Th1 (IFN-γ, TNF-α), Th2 (IL-4) and T regulatory 1 cell (Tr1) (IL-10) cytokines in the supernatants of PBMC cultures. Stimulation index in response to PHA decreased at month 3 as well as T cell precursor frequencies specific for TT with similar trends for OM-89-specific T cell precursor frequencies. OM-89 induced a strong production of IL-10, a significant decrease in IL-4 production while TNF-α and IFN-γ production tended to decrease during the study.

Our results suggest that OM-89 has immunomodulatory properties by inducing changes in PBMC cytokines release suggestive of an induced Tr1 response to OM-89.     

Effect of CD80 and CD86 blockade and anti-interleukin-12 treatment on mouse acute graftversus-host disease

We investigated the efficacy of a combination of anti-CD80 and CD86 (CD80 + 86) monoclonal antibodies (mAb), anti-interleukin (IL)-12 mAb, or both, for prophylaxis in a mouse acute graft-versus-host-disease (GVHD) model. The treatment with a combination of anti-CD80 + 86 mAb efficiently reduced the lethality of GVHD, whereas mAb against either CD80 or CD86 alone had an effect. A delay in lymphocyte reconstitution and GVHD-associated histological changes in organs was observed at 30 days post-bone marrow transplantation (BMT) even in the anti-CD80 + 86 mAb-treated mice, although these manifestations were resolved by 100 days. In vitro, host alloantigen-specific T cell proliferative responses and generation of CTL were significantly reduced by anti-CD80 + 86 treatment. Furthermore, anti-CD80 + 86 mAb preferentially inhibited the production of interferon (IFN)-γ, but not IL-4 and IL-10, when cultures were assayed at 21 days. Although the anti-IL-12 mAb treatment alone inhibited the generation of cytotoxic T lymphocytes and IFN-γ production in vitro, administration of anti-IL-12 mAb in vivo reversed the beneficial effects of anti-CD80 + 86 treatment on host survival post-BMT. The adverse effect of anti-IL-12 treatment seems to result from impairment of natural immunity and hematopoiesis, rather than as a consequence of an incomplete blockade of T helper (Th)1 responses. Our results suggest that the prevention of GVHD-induced death results from the efficient blockade of Th1 cell activation by the anti-CD80 + 86 treatment. However, further treatment is required for a complete prevention of GVHD, which seems to be partly mediated by Th2 cells.     

GM1, a ganglioside that specifically enhances immunoglobulin production and proliferation in human plasma cells

The effects of gangliosides on human plasma cell responses were studied. Among the various gangliosides tested, only GM1 enhanced immunoglobulin (Ig) production and proliferation in the human plasma cell lines, IM-9 and AF-10, while other gangliosides (GM2, GM3, GD1a, GD1b, GD3, GT1b, and GQ1b) had no effect. Among the various cytokines tested, including interleukin (IL)-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12, IL-13, interferon (IFN)-α and IFN-γ, only IL-6 enhanced Ig production and proliferation in IM-9 and AF-10 cells. However, the enhancement of plasma cell responses by GM1 was specific and was not mediated by IL-6, since GM1 activity was blocked by anti-GM1 monoclonal antibody (mAb), but not by control IgM, anti-IL-6 Ab or the anti-IL-6 receptor mAb, PM1. Conversely, the enhancement by IL-6 was blocked by anti-IL-6 Ab and PM1, but not by anti-GM1 mAb. GM1, but not other gangliosides, also enhanced Ig production and proliferation in freshly separated plasma cells from patients with plasma cell leukemia and in plasma cells generated in vitro. These actions of GM1 were specifically blocked by anti-GM1 mAb, but not by anti-IL-6 Ab or PM1. These results indicate that GM1 may be an important regulator of plasma cell responses.     

Cytokine Regulation of Human Immune Response to Schistosoma mansoni: Analysis of the Role of IL-4, IL-5 and IL-10 on Peripheral Blood Mononuclear Cell Responses

The role of cytokines on the in vitro proliferative response of peripheral blood mononuclear cells (PBMC) from Schistosoma mansoni infected patients to soluble egg (SEA) and adult worm antigens (SWAP) were evaluated. The results obtained demonstrated that the proliferative response of PBMC from chronic intestinal (INT) patients to SEA and SWAP is increased by the blockage of IL-10 with specific monoclonal antibodies (MAb). The effects of these antibodies were readily reversed by the addition of recombinant IL-10. In contrast, no effect was observed on the PBMC response of acute and hepatosplenic patients (HS) in the presence of anti-IL-10. Anti-IL-4 antibodies decreased the PBMC response of the intestinal (INT) and HS individuals to SEA and SWAP, and the PBMC response of acute patients to SEA but not to SWAP. Addition of anti-IL-5 MAb did not decrease the PBMC response of acute patients to SEA or SWAP. These results suggested that IL-10 has an important role in the modulation of the immune response in chronic asymptomatic patients and that this cytokine may be an important factor in controlling morbidity.     

Th1 (IL-2, interferon-gamma (IFN-γ)) and Th2 (IL-10, IL-4) cytokine production by peripheral blood mononuclear cells (PBMC) from patients with systemic lupus erythematosus (SLE)

We investigated the production of IL-2, IFN-γ, IL-10 and IL-4 by PBMC from 24 patients with SLE and 10 healthy individuals. Basal and mitogen-stimulated (lipopolysaccharide and phytohaemagglutinin (LPS + PHA)) cytokine production was determined in a whole blood assay (WBA). Supernatants were collected and assayed with specific ELISAs. Although the IL-2 and IFN-γ contents did not differ significantly between patients and controls under both conditions, statistically significant correlations were found between each cytokine and disease activity (SLAM index) after stimulation (respectively, r= 0.501, P = 0.01 and r = 0.631, P = 0.001). PBMC IL-10 production was significantly higher for patients than controls (P = 0.05), but no correlation between IL-10 levels and the SLAM index was obtained. IL-4 production was not statistically different between SLE patients and controls. For stimulated WBAs, the IL-10/IL-2 and IL-10/IFN-γ ratios were significantly correlated with disease severity (P = 0.02; P = 0.001, respectively). Overall, our data suggest that SLE is characterized by an elevated production of IL-10, reflecting the basal state of activation of the immune system. During exacerbation of SLE, IL-2 and IFN-γ are synthesized in larger amounts and may cause the tissue damage observed.     

Elevated Serum Levels of IL-10 and IFN-γ in Patients with Acute Plasmodium falciparum Malaria

Serum levels of interleukin-10 (IL-10) and interferon-γ (IFN-γ) were determined in 37 patients with acute Plasmodium falciparum malaria in Bangkok, Thailand. Serum levels of IL-10 and IFN-γ were markedly elevated in patients with malaria prior to treatment (717 ± 260 pg/ml versus 2.2 ± 1.3 pg/ml in healthy controls; 123 ± 71 pg/ml versus 29 ± 9 pg/ml, respectively; mean ± SD). Serum levels of IFN-γ and IL-10 dropped significantly during treatment and were normal 14 and 21 days, respectively, after treatment was started. Prior to therapy a correlation between serum levels of IFN-γ and IL-10 existed (r = 0.563). These results suggest that stimulatory and inhibitory cytokines for macrophage activation and/or antibody production (i.e., TH1- and TH2-type immunoreaction, respectively) are coexpressed during acute P. falciparum infection and stress the multifactorial network between host and parasite in malaria immunology.     

Prevention of experimental autoimmune uveoretinitis by monoclonal antibody to interleukin-12

Experimental autoimmune uveoretinitis (EAU) induced by immunization with interphotoreceptor retinoid-binding protein (IRBP), a retinal self antigen, has been regarded to be a typical T helper type 1 (Th1)-mediated inflammatory disease. In this study, we examined the effect of a neutralizing monoclonal antibody (mAb) to interleukin-12 (IL-12), which has been known to play a critical role in the Th1 differentiation, on the development of EAU. While 9 of 13 control mice developed EAU by the immunization with IRBP, none of 12 mice developed EAU when given anti-IL-12 mAb 1 day before immunization. These mice did not develop EAU even after a rechallenge with IRBP on day 30, indicating that a protective mechanism had been established by the anti-IL-12 treatment. The proliferative response of splenocytes to IRBP in vitro was not significantly impaired, but the production of IL-2 and IFN-γ was greatly reduced by the anti-IL-12 treatment. Moreover, production of IL-5 and expression of IL-4 mRNA were increased by the anti-IL-12 treatment. Consistently, IgG2a anti-IRBP serum antibodies were decreased and IgG1 were increased. Administration of a neutralizing anti-IL-4 mAb at the time of IRBP rechallenge reversed the protection established by the anti-IL-12 treatment at the primary immunization. These results indicate that the anti-IL-12 treatment at the IRBP priming not only prevented the development of pathogenic Th1 cells, but also induced suppressive Th2 cells that protect the animals from further challenge with the same antigen.     

Selective stimulation of T helper 2 cytokine responses by the anti-psoriasis agent monomethylfumarate

Type 2 cytokines are thought to have a protective role in psoriasis vulgaris by dampening the activity of T helper 1 (Th1) lymphocytes. The aim of the present study was to determine the effect of monomethylfumarate (MMF), the most active metabolite of the new anti-psoriatic drug Fumaderm®, on the production of cytokines and the development of Th subsets. MMF was found to enhance interleukin (IL)-4 and IL-5 production by CD2/CD8 monoclonal antibody-stimulated peripheral blood mononuclear cells (PBMC) in a dose-dependent manner. Maximal effects of MMF were found at a concentration of 200 μM and resulted in tenfold enhanced levels of IL-4 and IL-5 production. MMF did not affect the levels of IL-2 production, interferon (IFN)-γ production or proliferative T cell responses in these cultures. Similar effects of MMF were observed in cultures of purified peripheral blood T cells indicating that this compound can act directly on T cells. MMF did not influence cytokine production by purified CD4⁺CD45RA⁺ (unprimed) T cells, but greatly enhanced IL-4 and IL-5 production without affecting IFN-γ production by purified CD4⁺CD45R0⁺ (primed) T cells. Furthermore, MMF also augmented IL-4 and IL-5 production in established Th1/Th0 clones that were stimulated with CD2/CD28 monoclonal antibody. Finally, when PBMC were challenged with Mycobacterium tuberculosis that typically induces Th1 recall responses with strong IFN-γ secretion, MMF again appeared to induce high levels of IL-4 and IL-5 secretion while IFN-γ production was unaffected. These results may be relevant for the development of therapeutic regimens designed to correct inappropriate Th1 subset development in immunopathologic conditions.     

类风关滑膜浸润T细胞特性与致病机制研究

为研究类风湿关节炎时关节滑膜浸润性T细胞生物学特性与致病机制 ,对 10例RA患者滑膜液中淋巴细胞的免疫表型、细胞因子分泌格局与趋化因子受体表达进行了分析。用双色荧光标记法分别测定滑膜液中和外周血淋巴细胞表型与趋化因子受体表达。用ELISA方法检测滑膜液与外周血中IFN γ、IL 10、IL 4与IL 12的含量。结果是滑膜液中的CD4 + T淋巴细胞为 4 0 0 %± 11% ,CD8+ T细胞为 34 0 %± 6 % ,CD4 + 与CD8+ T细胞的比值为 1 2 ,显著低于外周血中CD4 /CD8的比值。滑膜液中CD3和CD2 5双阳性的活化T细胞占 16 %± 6 0 %。趋化因子受体CCR5表达较低 ,与外周血无明显差异。但CX CR3表达水平较高 ,为 16 %± 4 0 % ,远远高于外周血 (仅为 0 5 %± 0 3% )。IFN γ在滑膜液中含量很高 ,达 (36 6 7± 4 3 2 )pg/ml,而外周血中含量仅为 (2 0 1± 3 2 )pg/ml。IL 4含量未能测得 (<15pg/ml ) ,与外周血相似。IL 12含量为 (4 19 9±89 2 )pg/ml,远高于外周血中的含量 (6 5 32± 34 2 )pg/ml。IL 10含量为 (187 7± 34 5 )pg/ml,高于外周血中的含量 (85±12 7)pg/ml。在所测细胞因子中 ,关节滑膜液中IFN γ和IL 12的含量与外周血相比具有显著的统计学差异。表明RA关节滑膜液中有相当数量的T细胞浸润。这些T细胞     

American cockroach Cr-PI allergen induces lymphocyte proliferation and cytokine production in atopic patients

Background Previous studies have shown cockroach-induced antigen-specific IgF-mediated asthma. In cockroach-Infested areas, more then 50% of asthmatic subjects may have positive skin reactions to this allergen. Partial purified Cr-PI allergen from American cockroaches contains allergens with molecular weights of 72 and 78k Da; however, little is known about its eifect on the lymphoeyte proliferation and cytokine production. Objective IgE synthesis is known to be regulated by interleukin-4 (IL-4) and interferon gamma (IFN-γ). Therefore, we studied Cr-PI allergen-induced cytokine production in atopic patients and healthy normal controls to understand each factors’ role in the disease. Methods Peripheral blood mononuclear cells (PBMC) from cockroach skin-sensitive patients and controls were stimulated with mitogen and Cr-PI for proliferative response and cytokine production. Cr-PI antigen-specific T-cell cultures of atopic patients and healthy normal controls were used to test C r-PI-lnduced proliferation and cytokine mKNA expression. Results PMBC ot atopic subjects showed a significantly (P < 0.01) higher stimulation index for Cr-PI induced proliferation (SI = l l.8.3.7) when compared with that of non-atopic subjects (SI =4.1 ± 0.8) and cord bloods (SI = 2.1 ± 0.4). Cr-Pl-induced IL-4 was observed only in the PBMC of atopic patients, whereas Cr-PI-induced IFNγ was detected in both atopic patients and normal controls. Likewise, Cr-PI-induced IL-4 mRNA expression in T-cell cultures was detected in all atopies but only one of nine controls. Conclusion IL-4 mKNA expression and IL-4 production in PBMC and T-cell cultures of atopic patients showed good correlation with clinical symptoms, skin-reactivity, specific IgE and proliferative response to Cr-PL These results suggests that cockroach allergen may be a hidden cause of asthma and other atopie diseases.     

Antigen-stimulated IL-4, IL-13 and IFN-γ production by human T cells at a single-cell level

To understand the intricate balance and the coordinate expression of the Th1 and Th2 cytokines following a natural mode of T cell triggering, antigen-stimulated IL-4, IL-13 and IFN-γ production was studied in primary peripheral blood mononuclear cell cultures at a single-cell level. Cells from filariasis patients who respond to parasite antigen by producing not only IFN-γ but also IL-4 and IL-13 were stimulated with Brugia malayi adult worm antigen and analyzed for co-expression of cytokines by intracellular staining. IL-4 and IL-13 were frequently co-expressed (54 % of IL-4⁺ cells stained for IL-13 and 29 % of IL-13⁺ cells expressed IL-4 at all time points), whereas IFN-γ expression was totally segregated from both IL-4 and IL-13. These data indicate that in human peripheral T cells the co-expression of the dominant Th1 and Th2 cytokines within a single cell is a rare event and that IL-13 is clearly more frequently associated with a Th2 than a Th1 type response in primary T cell cultures.     

Interleukin-12 is required for interferon-γ production and lethality in lipopolysaccharide-induced shock in mice

Several cytokines, in particular tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), have been shown to be responsible for pathological reactions which may lead to shock and death observed in infection with Gram-negative bacteria and in response to endotoxins (lipopolysaccharides, LPS). Priming of mice with the avirulent Bacille Calmette Guérin (BCG) vaccine strain of Mycobacterium bovis increases the sensitivity of mice to the lethal effect of LPS and results in an efficient priming for cytokine production. In response to low doses (1 γg/mouse) of LPS, BCG-primed mice produce interleukin-12 (IL-12) which controls IFN-γ production, as demonstrated by the ability of neutralizing anti-IL-12 antibodies to suppress IFN-γ production. However, the concentration of the biologically active IL-12 p70 heterodimer is similar in the serum of both BCG-primed or unprimed mice, reaching levels of 1–3 ng/ml at 3–6 h after LPS injection, whereas IFN-γ production was observed only in BCG-primed mice. The priming effect of BCG on IFN-γ production appears to be mostly due to its ability to increase TNF-α production, which acts as cofactor with LPS-induced IL-12 in inducing IFN-γ production, as shown by the ability of injection of TNF-α and LPS (1 γg/mouse), but not LPS alone, to induce IFN-γ production. However, in addition to TNF-α, other LPS-induced cofactor(s) are required in cooperation with IL-12 to induce optimal IFN-γ production, because co-injection of TNF-α and IL-12, sufficient to induce serum concentrations of both cytokines higher and more persistent than those obtained by injection of LPS, was not sufficient to induce IFN-γ production in vivo. Neutralizing anti-IL-12 antibodies, in addition to inhibiting the in vivo LPS-induced IFN-γ production, also completely protect BCG-primed mice injected with up to 10 μg of LPS from shock-induced death. Thus, IL-12 is required for IFN-γ production and lethality in an endotoxic shock model in mice.     

绿脓杆菌制剂与IL-12在诱导人NK细胞IFN-γ产生中的协同作用

探讨绿脓杆菌制剂(piliated Pseudomonas Aeruginosa,PPA)与IL-12协同诱导人PBMC和NK细胞IFN-γ的产生。分离健康人PBMC和纯化NK细胞分别与培养液、PPA、IL-12或PPA+IL-12共同培养,利用酶联免疫吸附法(ELISA)检测无细胞培养上清中IFN-γ的水平。同时采用流式细胞仪在单个细胞水平上分析PPA和IL-12诱导IFN-γ产生的淋巴细胞亚群。结果显示,单独应用亚适剂量的IL-12或PPA刺激人PBMC或纯化NK细胞,不能诱导或只能诱导低水平IFN-γ的产生。当PPA和IL-12共同与人PBMC或纯化NK细胞孵育后,PPA呈时间和剂量依赖性与IL-12协同诱导PBMC和纯化NK细胞产生大量IFN-γ。细胞亚群分析的结果表明,PPA和IL-12协同诱导CD56+NK细胞产生IFN-γ,但对CD4+T和CD8+T细胞无明显作用。PPA与IL-12协同促进NK细胞IFN-γ的产生,提示PPA和IL-12能直接刺激NK细胞发生免疫应答。     

Interleukin-12 in human boutonneuse fever caused by Rickettsia conorii

Interleukin (IL)-12 contributes to the resistance against a number of intracellular pathogens. We examined the potential biological role of IL-12 by studying peripheral blood mononuclear cells (PBMC), its production and its effect on cytokine synthesis in 20 Sicilian patients with boutonneuse fever (BF) caused by Rickettsia conorii. Data indicate that PBMC from acute BF patients were able to produce IL-12 in response to in vitro stimulation with rickettsial antigen (Ag): this production was higher than that detected in healed patients. Monocytes were the main source of IL-12 by PBMC from BF patients. IL-12 secretion by in vitro Ag-stimulated PBMC from BF patients was potentiated by recombinant interferon gamma (IFN-gamma) or anti-IL-10 monoclonal antibodies (MoAbs). Furthermore, the treatment with anti-IL-12 MoAbs reduced the IFN-gamma synthesis. These results indicate that treatment of PBMC from acute BF patients with IL-12 shifted the response toward a Th1-type cytokine response. Furthermore, IL-12 and IFN-gamma are interdependent and they may be associated with the immunity against rickettsias.     

Polymerase chain reaction quantification of cytokine messenger RNA expression in peripheral blood mononuclear cells of patients with acute exacerbations of asthma: effect of glucocorticoid therapy

We have measured the expression of messenger ribonucleic acid (RNA) (mRNA) encoding inlerleukin-5 (IL-5), IL-4. IL-2 and interteron-γ (IFN-γ) in peripheral blood mononuclear cells (PBMC) from 10 patients with acute exacerbations of asthma and nine non-asthmatic controls. Measurements were repealed in seven of the asthmatics following 7 days of oral glucocorticoid therapy. Total RNA was extracted from the PBMC, reverse transcribed using oligo-(dT) primers and aliquots of the resulting complementary DNA (cDNA) amplified using the polymerase chain reaction (PCR) in the presence of cytokine-specific primers under non-saturating conditions. PCR products were quantified on a relative basis after Southern blotting and probing with radiolabelled internal oligonucleotide probes by computer assisted densitometry of blot autoradiographs. The relative amounts of IL-5 mRNA in PBMC from the asthmatic patients prior to glucocorticoid therapy were greater (P < 0.01) than those in PBMC from non-asthmatic controls. In contrast, there were no differences in the relative amounts of IL-4. IL-2 and IFN-γ mRNA. In the asthmatics, the relative amounts of IL-5 mRNA correlated with the peripheral blood eosinophil counts (P= 0.02). After oral glucocorticoid therapy of the asthmatics, lung function improved and the relative amounts of PBMC IL-5 mRNA were reduced (P= 0.04) and no longer differed from those in PBMC from non-asthmatic controls. Glucocorticoid therapy was not associated with significant changes in the relative amounts of PBMC IL-4. IL-2 and IFN-γ mRNA. PBMC from alopic subjects contained significantly greater quantities of IL-4 mRNA (P - 0.04) but not IL-5, IL-2 and IFN-γ mRNA compared with non-atopic subjects regardless of their asthmatic status. We conclude that PBMC of patients with acute exacerbations of asthma demonstrate elevated expression of mRNA encoding IL-5, but not IL-2, IL-4 and IFNγ and that the clinical improvement associated with glucocorticoid therapy is associated with a reduction of IL-5 mRNA expression. We further conclude that elevated expression in PBMC of mRNA encoding IL-4 is a feature of atopy but not of asthma. These observations suggest that IL-5 synthesis by activated T-lymphocytes may be relevant to the pathogenesis of asthma, and that inhibition of this release by glucocorticoids may at least partly explain their therapeutic effect in this disease.