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.     

Induction of macrophage nitric oxide production by interferon-γ and tumor necrosis factor-α is enhanced by interleukin-10

Interleukin-10 (IL-10) has been reported to inhibit nitric oxide (NO) synthesis and microbicidal activity of interferon-γ (IFN-γ)-stimulated macrophages (MΦ) by preventing the secretion of tumor necrosis factor-α (TNF-α) which serves as an autocrine activating signal. We have examined the effects of recombinant IL-10 on the capacity of IFN-γ together with exogenous TNF-α to induce NO synthesis by bone marrow-derived MΦ. Under these conditions and in contrast to its reported deactivating potential, IL-10 strongly enhanced NO synthesis measured as nitrite (NO) release (half maximal stimulation at approximately 10 U/ml). IL-10 further increased NO production by MΦ stimulated in the presence of optimal concentrations of prostaglandin E₂, a positive modulator of MΦ activation by IFN-γ/TNF-α. Increased steady state levels of NO synthase mRNA were observed in 4-h IFN-γ/TNF-α cultures and enhanced NO release was evident 24 h but not 48 h after stimulation. These results suggest that the effects of IL-10 on MΦ function are more complex than previously recognized.     

IL-18在实验性暴发型肝衰竭发病机制中的作用

为探讨IL 18在暴发型肝衰竭发生中的表达变化及对其他细胞因子的调控作用。采用D 氨基半乳糖 (D Gal) 90 0mg/kg与脂多糖 (LPS ) 10 μg/kg诱导BALB/c小鼠暴发型肝衰竭 ,检测不同时间点血清转氨酶 (ALT、AST )和肝组织病理、DNA梯形条带 ,评估肝损伤情况 ;用半定量RT PCR和相应的分析软件分析不同时间点肝组织中IL 18mRNA、TNF αmRNA和IFN γmRNA表达及ELISA方法检测血浆IL 18、TNF α和IFN γ的蛋白表达。结果 :D Gal/LPS给予后 4h血清转氨酶明显升高 ,7h小鼠开始死亡 ,10h死亡率达 80 %。肝组织病理学检查发现 ,5h肝窦扩张、炎性细胞浸润、枯否细胞增生 ;7h肝细胞大量凋亡、坏死或肝组织出现大量出血性坏死 ;5h电镜示肝细胞核仁碎裂、线粒体肿胀或空泡变性 ;7h核仁边聚 ,呈半月型 ,表现为典型的凋亡形态学变化 ,线粒体大部分空泡变性。DNA电泳显示 5h始出现梯形条带。正常小鼠肝组织IL 18mRNA有少量表达 ,TNF αmRNA、IFN γmRNA微量表达。给药后 ,三者的mRNA分别在 1h、 2h、 3h达高峰 ,血浆中TNF α、IFN γ水平与其mRNA变化显著正相关 (rTNF α=0 4 3,P =0 0 1;rIFN γ=0 6 9,P <0 0 0 1) ,而血浆IL 18与其mRNA表达无明显相关 (r= 0 12 ,P =0 2 5 )。本实验诱导的暴发型肝衰竭模型中 ,肝细?     

Tumour necrosis factor (TNF) and TNF-related molecules in HIV-1+ individuals: relationship with in vitro Thl/Th2-type response

We examined the secretion and expression by peripheral blood mononuclear cells (PBMC) of TNF-α and TNF-related molecules with regard to Th1/Th2-type cytokine production. In 76 HIV⁺ patients at different disease stages and in 25 controls we measured cytokine (TNF-α/β, interferon-gamma (IFN-γ), IL-2, IL-4, IL-10), and activation marker secretion (sCD4, sCD8, sCD30) in phytohaemagglutinin (PHA)-stimulated and unstimulated PBMC cultures by ELISA, and membrane-bound TNF-α and CD30 expression by flow cytometry. We found an expansion of the TNF system in HIV⁺ individuals, that positively correlated with TNF-α, IFN-γ and sCD8, probably representing activation of the cytotoxic compartment. In advanced disease these correlations disappeared, and TNF-α and TNF-related molecules positively correlated with IL-10. Our results are in line with the hypothesis that an expanded TNF system is immunopathological in conjunction with Th2-type immunity in the advanced stage of disease and with the inexorable progression to disease seen when both IL-10 and TNF-α are elevated.     

Changes in intracellular cytokine levels in newborn and adult lymphocytes induced by HSV-1

Changes in the expression of intracellular interleukin-2 (IL-2), interleukin-4 (IL-4), interferon (IFN)-γ, and tumor necrosis factor (TNF)-α in newborn and adult lymphocytes induced by herpes simplex virus (HSV)-1 were examined. Cord blood mononuclear cells (CBMC) or adult peripheral blood mononuclear cells (PBMC) were infected with HSV-1 and cultured with phorbol 2-myristate 13-acetate (PMA) plus ionomycin in the presence of monensin for 4 hr. Surface antigen and intracellular cytokines were stained simultaneously and analyzed by flow cytometry. The percentage of cells that expressed IL-2, IFN-γ, and TNF-α was significantly increased in HSV-1-infected CD3⁺, CD4⁺, CD8⁺, CD45RA⁺, and CD45R0⁺ lymphocytes compared with uninfected lymphocytes from adult PBMC. The percentage of cells that expressed IL-2 and TNF-α was increased significantly in HSV-1-infected CD3⁺, CD4⁺, CD8⁺, and CD45RA⁺ lymphocytes compared with uninfected lymphocytes from CBMC. IFN-γ was under the detectable level in HSV-1-infected and uninfected lymphocytes from CBMC. Intracellular IL-4 was not detected in HSV-1 or in uninfected lymphocytes from PBMC and CBMC. These results demonstrate that HSV-1 enhances intracellular levels of IL-2, IFN-γ, and TNF-α in adult lymphocytes and defective IFN-γ production in cord blood. J. Med. Virol. 56:145–150, 1998. © 1998 Wiley-Liss, Inc.     

大鼠胰岛β细胞损伤中IL-18的作用研究

新生Wistar大鼠离体胰岛与细胞因子孵育后 ,观测胰岛素释放和一氧化氮 (NO )生成的变化 ,并用逆转录 聚合酶链反应 (RT PCR )观察IL 18受体信号链 (IL 18Rβ )mRNA的表达水平。结果表明 :(1) 0 6 2 5～ 10nmol/L基因重组小鼠 (rm )IL 18孵育胰岛 2 4h后 ,对累积的和葡萄糖刺激的胰岛素释放以及NO生成均无显著效应 ;(2 ) 2 0 0U/ml基因重组大鼠 (rr)γ干扰素 (IFN γ )或 2 5 0U/ml基因重组人 (rh )肿瘤坏死因子 α (TNF α)单独存在对胰岛素释放和NO生成均无明显效应 ,也不能促使 10nmol/LrmIL 18对胰岛素释放和NO生成产生影响 ;(3) 2 0 0U/mlrrIFN γ +2 5 0U/mlrhTNF α或 15pg/mlrhIL 1β均明显促进NO生成和抑制胰岛素释放 ,而 10nmol/LrmIL 18则不影响IFN γ +TNF α或IL 1β的上述效应 ;(4 )即使经IL 1β和 (或 )IFN γ +TNF α或IL 12孵育后 ,大鼠胰岛素瘤 (RIN )细胞或离体大鼠胰岛仍未见IL 18RβmRNA的表达。提示IL 18在细胞因子所致胰岛β细胞损伤中不发挥直接作用 ,原因是IL 18受体在胰岛 β细胞中不表达。     

IFN-γ-induced TNF-α is a prerequisite for in vitro production of nitric oxide generated in murine peritoneal macrophages by IFN-γ

The effect of IFN-γ to stimulate formation of nitric oxide (NO) by normal murine peritoneal macrophages (Mϕ) has been found to be completely dependent on the ability of IFN-γ to activate secretion of TNF-α. The NO-stimulatory effect of IFN-γ was abolished by anti-TNF-α antibodies, the inhibitory intervention of which could be fully reversed by exogenously supplied TNF-α. Accordingly, the failure of Mϕ from C3H/HeJ mice to secrete TNF-α upon stimulation with IFN-γ was associated with their complete incapability to generate NO, unless they were simultaneously treated with IFN-γ + TNF-α. Collectively, the data document that similar to the NO up-regulatory action of other cytokines, the effect of IFN-γ is not independent, but depends on a synergistic cooperation with the self-produced TNF-α. The findings thus indicate that a widespread opinion claiming that IFN-γ per se is able to stimulate biosynthesis of NO needs revision.     

IFN-α cannot substitute lack of IFN-γ responsiveness in cells of an IFN-γR1 deficient patient

Patients with complete IFN-γR deficiency are unable to respond to IFN-γ and have impaired Th1-immunity and recurrent, severe infections with weakly virulent Mycobacteria. Since IFN-α and IFN-γ share signalling pathways, treatment with IFN-α has been proposed in complete IFN-γR deficiency. We stimulated cells from healthy controls and from a patient lacking IFN-γR1 with IFN-α and IFN-γ, to establish whether IFN-α would substitute for IFN-γ effects. IFN-α induced STAT1 phosphorylation in monocytes of the IFN-γR1(-/-) patient, but did not prime for LPS-induced IL-12p70, IL-12p40, IL-23 or TNF production. In control cells, IFN-α inhibited the priming effect of IFN-γ on LPS-induced pro-inflammatory cytokine release. Finally, IFN-γ but not IFN-α induced killing of M. smegmatis in cultured macrophages. In conclusion, no evidence was found to support the use of IFN-α in IFN-γR-deficient patients as intervention against mycobacterial infection; on the contrary, treatment of individuals with IFN-α may even adversely affect host defence against Mycobacteria.     

Interleukin-12 but not interferon-γ production correlates with induction of T helper type-1 phenotype in murine candidiasis

By means of polymerase chain reaction-assisted mRNA amplification, we have monitored message levels of interleukin (IL)-12 in splenic macrophages and of interferon-γ (IFN-γ), IL-4, and IL-10 in CD4⁺ and CD8⁺ T cells using Candida albicans/host combinations that result either in a T helper type-1 (Th1)-associated self-limiting infection (“healer mice”) or in a Th2-associated progressive disease (“nonhealer mice”). The timing and pattern of message detection did not differ qualitatively by the expression of IFN-γ or IL-10 mRNA in CD4⁺ and CD8⁺ cells from healer (i.e. PCA-2 into CD2F1) vs. nonhealer (i.e. CA-6 into CD2F1 or PCA-2 into DBA/2) mice. In contrast, IL-4 mRNA was uniquely expressed by CD4⁺ cells from nonhealer animals. IL-12p40 was readily detected in macrophages from healer mice but was detected only early in infection in mice with progressive disease. Cytokine levels were measured in sera, and antigen-driven cytokine production by CD4⁺ and CD8⁺ cells was assessed in vitro, while IFN-γ-producing cells were enumerated in CD4^? CD8^? cell fractions. Overall, our results showed that (i) antigen-specific secretion of IFN-γ protein in vitro by CD4⁺ cells occurred only in healing infection; (ii) IL-4- and IL-10-producing CD4⁺ cells would expand in nonhealer mice in the face of high levels of circulating IFN-γ, likely released by CD4^? CD8^? lymphocytes; (iii) a finely regulated IFN-γ production correlated in the healer mice with IL-12 mRNA detection, and IL-12 was required in vitro for yeast-induced development of IFN-γ-producing CD4⁺ cells. Although the mutually exclusive production of IL-4/IL-10 and IFN-γ by early CD4⁺ cells may be the major discriminative factor of cure and noncure responses in candidiasis, IL-12 rather than IFN-γ production may be an indicator of Th1 differentiation.     

Role of cytokines in anti-implantation activity of H2 receptor blockers in albino wistar rats

In this study, the negative effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD) on the immune system and body weight gain of rats and the preventive effects of curcumin were examined. For this purpose, 3–4 months old 128 Wistar albino rats with 280?–?310?g body weights were used. The 2?μg/kg dose of 2,3,7,8-TCDD and 100?mg/kg dose of curcumin were dissolved in corn oil and orally given to the rats found in the experimental and control groups. Then, the serum samples were taken from all rats at 15, 30, 45 and 60^th days to analyzed for the determination of TNF-α, IFN-γ, IL-12 and IL-13 levels by ELISA method. The data of body weight gain was measured at 15, 30, 45 and 60^th days. The results indicated that 2,3,7,8,3,7,8-TCDD caused to increase significantly (p?<?0.05) in serum TNF-α levels. However, it caused significantly (p?<?0.05) decreases in the levels of IFN-γ, IL-12 and IL-13 in rats. On contrary, curcumin increased IFN-γ, IL-12 and IL-13 levels, but decreased TNF-α level in rats. Additionally, TCDD caused significantly (P?<?0.01) reductions in the body weight gain. However curcumin reversed this effect of TCDD.

In conclusion, 2,3,7,8-TCDD significantly suppressed the humoral immunity and body weight gain in rats at doses of 2?μg/kg. However curcumin, which was found in some plants, eliminated the effect of TCDD on immune system and body weight when it was given together with 2,3,7,8-TCDD. It is thought that this effect may have occurred via curcumin and TCDD were binding aryl hydrocarbon receptor (AhR) competitively.     

Expression of pro-inflammatory cytokines by TCRαβ+ T and TCRγδ+ T cells in an experimental model of colitis

An inflammatory bowel disease (IBD) comparable to human ulcerative colitis is induced upon transfer of T cell-depleted wild-type (F1) bone marrow into syngeneic T cell-deficient (tgε26) mice (F1 → tgε26). Previously we have shown that activated CD4⁺ T cells predominate in transplanted tgε26 mice, and adoptive transfer experiments verified the potential of these cells to cause disease in immunodeficient recipient mice. Using flow cytometry for the detection of intracellular cytokine expression, we demonstrate in the present study that large numbers of CD4⁺ and CD8⁺ TCRαβ⁺ T cells from the intraepithelial region and lamina propria of the colon of diseased, but not from disease-free mice, produced interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). Large numbers of T cells from peripheral lymphoid tissues of these animals also expressed IFN-α and TNF-α, but few expressed interleukin-4, demonstrating g strong bias towards Th1-type T cell responses in these animals. TCRγδ⁺ T cells, typically minor constituents of the inflammatory infiltrate of the colon in F1 → tgε26 mice, also expressed IFN-γ at a high frequency upon CD3 stimulation. In light of these findings we examined the potential involvement of TCRγδ⁺ T cells by testing their ability to induce colitis in tgε26 mice. We report here that tgε26 mice transplanted with T cell-depleted bone marrow from TCRα^null and TCRβ^null animals developed IBD. Furthermore, disease in these mice correlated with the development of peripheral and colonic TCRαδ⁺ T cells capable of IFN-γ production. These results suggest that IFN-γ may be a common mediator of IBD utilized by pathogenic T cells of distinct phenotype.     

日本血吸虫重组Bb(pGEX-Sj14-3-3)疫苗免疫小鼠脾细胞因子的动态观察

目的探讨日本血吸虫重组双歧杆菌属两歧双歧杆菌(Bifidobacterium bifidum,Bb)(pGEX-Sj14-3-3)疫苗免疫Balb/c小鼠后脾细胞因子的动态变化。方法重组疫苗分别经口服灌胃及鼻腔粘膜接种小鼠;在免疫后0、2、4、6、8、10、12、14、16、18、20和22周各剖杀4只小鼠,取脾及分离脾细胞;脾细胞分别经未刺激、SjAWA和ConA刺激培养;收集培养的上清液,双抗体夹心ELISA法测定培养上清液的细胞因子水平。结果口服组小鼠脾细胞IFN-γ、IL-12、TNF-α和IL-10水平分别在免疫后2~12、6~8、2~12和2~8周显著升高,分别在免疫后8、8、6和4周达最高水平;鼻腔黏膜接种组小鼠脾细胞IFN-γ、IL-12、TNF-α和IL-10水平分别在免疫后2~20、2~10、2~16和2~16周显著升高,分别在免疫后2、2、4和4周达最高水平。结论重组Bb(pGEX-Sj14-3-3)疫苗能够诱导免疫小鼠产生有效的免疫应答。     

IFN-γ受体Ig融合蛋白对ConA诱导小鼠肝损伤的保护作用

本文研究γ 干扰素受体免疫球蛋白融合蛋白 (IFN γR Ig )对ConA诱导的小鼠细胞免疫性肝损伤的保护作用及机制。在Balb/c小鼠体内一次性静脉注射ConA 2 0mg/kg诱导细胞免疫性肝损伤模型 ,分别于模型建立前后不同时间腹腔注射 10mg/kgIFN γR Ig,观察该融合蛋白对小鼠血清谷丙转氨酶 (GPT )水平 ,细胞因子IFN γ、TNF α和IL 10分泌以及肝组织病理学变化的影响。结果表明IFN γR Ig预防给药明显改善肝脏损伤的组织学和血清学变化 ,降低GPT水平 ,减少肝脏中性粒细胞、单核细胞浸润 ;同时与模型对照小鼠相比血清IFN γ水平下降 ,TNF α分泌合成减少 ,IL 10水平明显增加。而IFN γR Ig通过早期结合并阻断内源性IFN γ ,提高IL 10的抗炎作用 ,减轻炎症细胞对肝脏的侵袭及IFN γ、TNF α的肝细胞破坏作用 ,保护免疫性肝损伤。     

Enhanced tumor necrosis factor suppression and cyclic adenosine monophosphate accumulation by combination of phosphodiesterase inhibitors and prostanoids

We investigated cooperative effects of phosphodiesterase (PDE) inhibitors and prostanoids on cyclic adenosine monophosphate (cAMP) accumulation and tumor necrosis factor (TNF)-α synthesis in human peripheral blood mononuclear cells (PBMC). PDE inhibitors alone induced only a small increase in cAMP levels in lipopolysaccharide (LPS)-stimulated PBMC. Cicaprost (a stable analogue of prostacyclin) and pentoxifylline added simultaneously to LPS-stimulated PBMC (2.0 × 10⁶/ml) induced a rapid increase of cAMP to a level of 100 nM that peaked within 10 min and remained at a plateau for up to 4 h. Thus combined prostanoids and PDE inhibitors enhanced cAMP accumulation. TNF-α suppression in the presence of pentoxifylline and prostanoids exceeded that of either drug alone. The potency of different PDE inhibitors (theophylline, pentoxifylline, penthy-droxifylline, albifylline, torbafylline, A 802715, amrinone and rolipram) to increase cAMP levels in combination with cicaprost was evaluated after 1 h of incubation. The dose-dependent increase of cAMP for all PDE inhibitors tested in this combined stimulation provided a useful tool for evaluating the potency of PDE inhibitors on cAMP accumulation. The effective concentration of PDE inhibitors, which raised cAMP levels to 300% of control, (EC³⁰⁰), correlated with the IC₅₀ for TNF-α suppression (r = 0.930, p = 0.007, with theophylline excluded from the analysis). Interestingly, by contrast, the specific type IV PDE inhibitor rolipram caused only a moderate rise of accumulated cAMP in the same cells. Our data support cAMP as an essential mediator for TNF-α suppression by PDE inhibitors. Furthermore, an enhanced inhibiting effect on TNF-α production may prove therapeutically advantageous. It may occur in inflammatory and infectious diseases in vivo, since high levels of endogenous prostaglandins are liberated in these conditions.     

Interferon-γ confers resistance to experimental allergic encephalomyelitis

In experimental allergic encephalomyelitis (EAE), T cells infiltrate the central nervous system (CNS) and induce inflammation. These CD4⁺ T cells secrete interferon (IFN)-γ, levels of which correlate with disease severity, and which is proposed to play a key role in disease induction. Many strains of mice are resistant to EAE. We have studied the effect of deletion of IFN-γ on the ability to induce EAE in resistant BALB/c-backcrossed mice. As expected, only 0–6 % of BALB/c or BALB/c-backcrossed mice developed EAE when immunized with myelin basic protein in adjuvant. Strikingly, abrogation of IFN-γ expression by targeted disruption of the IFN-γ gene (GKO mice) converted them to a susceptible phenotype. As many as 71 % of these IFN-γ-deficient mice developed EAE, a frequency comparable to that seen with the susceptible SJL/J strain. In addition, EAE was of unusually high severity in mice lacking IFN-γ. Immunological characteristics of disease in IFN-γ-deficient mice were comparable to those seen in susceptible (SJL/J) mice with EAE, including perivascular infiltration in the CNS and order-of-magnitude increases for both CD3 γ chain and TNF-α mRNA levels in the spinal cord. We thus demonstrate that lack of IFN-γ converts an otherwise EAE-resistant mouse strain to become susceptible to disease. Therefore, in BALB/c mice, IFN-γ confers resistance to EAE.     

Anti-inflammatory activity of phosphodiesterase (PDE)-IV inhibitors in acute and chronic models of inflammation

Inhibitors of cyclic nucleotide phosphodiesterases are known to suppress lipopolysaccharide (LPS)-induced tumour necrosis factor-alpha (TNF-α) production in vitro in human monocytes. The most potent of these have selectivity for type IV PDEs, suggesting that this class of PDE is the major type involved in the regulation of human TNF-α production. Using compounds of two distinct chemical structural classes, a quinazolinedione (CP-77 059) and a 4 arylpyrrolidinone (rolipram). we show here that PDE-IV-specific inhibitors are also potent in suppressing LPS-induced TNF-α production in vitro in sodium periodate-elicited murine macrophages (IC₅₀s of 1 and 33, respectively). We then report the in vivo anti-inflammatory effect of PDE-IV inhibition in five murine models of inflammation: (i) elevation of serum TNF-α induced by a subtethal LPS injection; (ii) LPS-induced endotoxic shock; (iii) LPS/galactosamine-induced endotoxic shock; (iv) carrageenan-induced paw oedema; and (v) adjuvant arthritis. Following a sublethal (5 μg/mouse) injection of LPS, serum TNF-α levels in mice peaked sharply, reaching concentrations of 3–12 ng/ ml 90 min after injection. In this sublethal LPS assay, CP-77 059 was about 30 times more potent than rolipram, with a minimum effective dose of 0.1 mg/kg versus 3 mg/kg for rolipram. This rank order is in keeping with the relative in vitro IC₅₀S for CP-77059 and rolipram, as well as their relative Ki against the human PDE-IV enzyme (46 nM and 220 nM, respectively). In LPS-induced endotoxic shock, rolipram and CP-77 059 at relatively high doses of 30 and 10 mg/kg, respectively, significantly reduced serum TNF-α levels, and also inhibited mortality 66%. In the LPS/galactosamine shock model, in which mice are rendered exquisitely sensitive to LPS by co-injection with galactosamine, only 0.1 μg of LPS/mouse Is necessary for serum TNF-α elevation and death. Both rolipram and the CP-77059 caused dose-dependent reduction of serum TNF-α and lethality. In the carrageenan-induced paw oedema model, in which there is a pronounced local TNF-α response (without a serum TNF-α elevation), rolipram significantly inhibited paw swelling as well as localized TNF-α levels in the paw. In the adjuvant arthritis model, a chronic model of inflammation also possessing localized TNF-α elevation in the inflamed paw, rolipram and CP-77059 suppressed ankle swelling and radiological evidence of joint damage. These data are consistent with a major role for PDE-IV in regulation of TNF-α production and inflammatory responses in murine systems. It suggests a potential therapeutic use for PDE-IV-specific inhibitors in inflammatory disease such as rheumatoid arthritis, septic shock and other inflammatory diseases where TNF-α has been postulated to be a contributing factor in the pathology of the disease.     

Comparison of the effects of interleukin-1α, interleukin-lβ and interferon-γ-inducing factor on the production of interferon-γ by natural killer

Interferon-γ inducing factor (IGIF) is a recently identified cytokine which stimulates the production of interferon-γ (IFN-γ) by T cells and enhances natural killer (NK) cell cytolytic activity. Protein fold recognition, structure prediction and comparative modeling have revealed that IGIF is a member of the interleukin (IL)-1 cytokine family and has prompted the designation IL-1γ. Here we report functional similarities between members of the IL-1 family by comparing the effects of IL-1α, IL-1β and IGIF on NK cell production of IFN-γ. All three IL-1 types enhanced NK cell production of IFN-γ when induced by IL-2 or IL-12, although at high concentrations (>10 ng/ml), IGIF was five- to tenfold more potent than IL-1α or IL-1β. This effect correlated with enhanced levels of mRNA for IFN-γ when NK cells were stimulated with IGIF plus IL-12. In contrast to IL-12 and IL-2, the ability of IGIF to stimulate NK cell production of IFN-γ was not increased by IL-1α or IL-1β. The ability of IGIF to enhance IFN-γ production was independent of the type I and type II IL-1 receptors or the IL-1R accessory protein. Together, these results identify IGIF as a potent stimulator of NK cell production of IFN-γ and demonstrate that the effect of IGIF on NK cell production of IFN-γ is similar to that of IL-1α and IL-1β but distinct from that of IL-12.