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。     

小檗碱对小鼠DTH及其体内几种细胞因子的影响

目的 :以二硝基氟苯 (DNFB)所致迟发型超敏反应 (DTH)小鼠模型观察小檗碱对小鼠DTH及其体内几种重要细胞因子的影响。方法 :采用 1%DNFB腹部致敏、耳廓发敏的方法建立DTH小鼠模型 ,以巨噬细胞NO2 -释放法测定血清IFN γ水平 ,胸腺细胞法检测IL 1水平 ,丝裂原激活的淋巴母细胞法检测IL 2水平 ,L92 9细胞结晶紫染色法测定TNF α水平。结果 :发现小檗碱可抑制DNFB诱导的小鼠DTH ,降低其血清IFN γ水平 ,抑制其腹腔MΦ产生IL 1及TNF α ,抑制其脾细胞产生IL 2。结论 :表明小檗碱有抑制小鼠DTH的作用 ,其机制可能是抑制了IFN γ、IL 1、TNF α、IL 2等细胞因子的产生和分泌 ,从而抑制免疫反应 ,减轻炎症损伤。     

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?     

碘化钠对人甲状腺细胞IL-6、IFN-γ和TNF-α基因表达的影响

本研究以 10 4 M碘化钠 (NaI)刺激单层培养的人Graves病 (GD )甲状腺滤泡上皮细胞 (TEC ) ,采用定性及半定量PCR技术检测刺激前后白介素 6 (IL 6 )、γ 干扰素 (IFN γ )和肿瘤坏死因子 α(TNF α )在细胞中的表达水平。结果表明 :(1) 3例GD组织均含有IL 6及IFN γmRNA ,2例检测到TNF α基因表达 ;(2 )基础状态下 ,3例TEC均表达IL 6基因 ,2例表达TNF α ,而所有样本均无IFN γmRNA ;(3)NaI不能诱导TEC产生IFN γmRNA ,对IL 6mRNA的表达亦无明显影响 ;(4 ) 1例TNF α阴性的TEC样本 ,经NaI刺激后 ,可表达mRNA ,2例原含有TNF α的TEC经刺激后 ,其mRNA的表达水平显著增加。提示碘可通过诱导或增强TEC表达TNF α ,导致自身免疫性甲状腺疾病的发生与发展。     

SARS-CoV感染者血清IFN-γ和TNF-α的动态变化及其意义

目的　探讨SARS患者血清IFN γ和TNF α在SARS冠状病毒感染免疫中的作用。方法　应用酶联免疫吸附法 (ELISA)测定广州地区 2 8例SARS冠状病毒感染患者双份血清IFN γ和TNF α的水平。实验数据采用两样本均数t检验法。结果　 2 8例SARS冠状病毒感染者急性期血清IFN γ和TNF α水平比正常健康对照组明显增高 (P <0 .0 5 ) ;恢复期血清IFN γ水平比正常健康对照组明显增高 (P <0 .0 5 )。感染病程第 1周 ,患者血清IFN γ水平达高峰 ,然后逐渐下降。SARS患者血清TNF α水平在病程第 2周达高峰 ,然后逐渐下降。结论　IFN γ和TNF α在SARS冠状病毒的致病与免疫过程中可能起重要作用     

两种HLA-B分子对外周血单个核细胞分泌细胞因子的影响

为了解HLA B2 7和B39分子对外周血单个核细胞 (PBMC )分泌IFN γ和TNF α的影响。我们将外源HLA B 2 70 4和B 390 5 2基因分别表达在HLAI类分子缺陷的K5 6 2细胞表面 ,与PBMC作用 12h后 ,用ELISA法检测IFN γ和TNF α的含量。结果显示 :HLA B2 7分子能显著抑制PBMC分泌IFN γ ,而对TNF α分泌的影响不显著 ;而HLA B39表达于K5 6 2细胞后 ,均不能影响IFN γ、TNF α分泌。提示HLA B2 7分子与HLA B39分子影响PBMC分泌细胞因子的能力不同     

HFRS患者血浆中TNF、sIL-2R、IL-6、IL-4和IFN-γ水平的变化及其意义

目的 :探讨肾综合征出血热 (HFRS)患者血浆中的TNF、sIL 2R、IL 6、IL 4和IFN γ水平的变化及其与血清中丙氨酸转氨酶ALT活性水平的相关性。方法 :利用双mAb夹心ELISA法检测HFRS患者血浆中细胞因子的水平 ,应用美国RA 10 0 0全自动生化仪检测患者血清中ALT的水平。结果 :HFRS患者血浆中TNF、IL 6、IL 4、IFN γ和sIL 2R水平分别为 (95 .82± 12 .0 4 )、(36 2 .4 6± 14 1.2 6 )、(17.76± 3.5 2 )、(116 .18± 19.80 )ng/L及 (89882 0± 12 72 0 0 )U/L ,健康对照组依次为 (17.89± 1.6 8)、(4 3.81± 18.0 8)、(4 .86± 1.14 )、(7.5 7± 2 .4 1)ng/L及(6 6 730± 2 96 90 )U/L、(P <0 .0 1) ;患者血清中ALT的水平也显著升高 ,为正常对照的 4 .4倍。通过相关性分析 ,发现TNF、sIL 2R、IL 6和IFN γ水平与患者血清中ALT的水平高度相关 (P <0 .0 1)。结论 :HFRS患者体内TNF、sIL 2R、IL 6和IFN γ水平显著升高 ,且与患者体内ALT水平的升高高度相关 ,提示HTNV感染所致肝脏的损伤可能与上述细胞因子水平的升高有关     

细胞因子对肾癌细胞株786-0Fas表达及其凋亡的调控

为研究细胞因子对肾癌细胞株 786 0Fas表达以及FasAb介导凋亡的影响 ,单独或联合应用IFN γ ,IFN α ,IL 2 ,TNF α刺激 786 0细胞株 ,并以Fas单克隆抗体 (FasAb )诱导其凋亡。结果发现 ,IFN α、IFN γ均能显著上调 786 0细胞的Fas表达 (P <0 0 1,P <0 0 1)并促进FasAb诱导的凋亡 (P <0 0 1,P <0 0 1) ;IL 2、TNF α对 786 0的Fas表达及FasAb诱导的凋亡均无影响 ;IL 2不能增强IFN α、IFN γ诱导的Fas表达 ,亦不能促进凋亡。TNF α能增强IFN α诱导的Fas表达并促进凋亡 ,但不影响IFN γ诱导的Fas表达及其凋亡。结果表明IFN γ、IFN α可增强肾癌细胞株 786 0的Fas表达 ,并促进FasAb介导的凋亡。但其对FasAb介导凋亡的敏感性并不完全取决于Fas表达水平     

活动性类风湿关节炎患者sICAM-1、sVCAM-1的变化及意义

目的 :测定活动性类风湿关节炎 (RA)患者血清中sICAM 1、sVCAM 1水平 ,探讨sICAM 1、sVCAM 1与IL 1、TNF、IFN γ及病情的关系。方法 :用酶联免疫分析法 (ELISA)检测 30例活动性RA患者与 30例健康对照者sICAM 1、sVCAM 1、IL 1、TNF、IFN γ水平。结果 :RA患者血清sICAM 1、sVCAM 1、IL 1、TNF、IFN γ水平明显高于正常对照组 (P<0 0 0 1) ,sICAM 1与IL 1、IFN γ正相关 ,与RF亦呈正相关 ,sVCAM 1与IL 1、TNF、IFN γ正相关 ,与ESR、CRP、Stock指数正相关。结论 :RA患者血清sI CAM 1、sVCAM 1水平显著升高 ,sICAM 1、sVCAM 1可能参与RA发病过程 ,sICAM 1可作为判断病情严重性的指标 ,sVCAM 1可作为观察病情活动性的指标。     

丙型肝炎病毒感染患者PBMC细胞因子的分泌水平

目的 :检测丙型肝炎病毒 (HCV)感染患者外周血单个核细胞(PBMC)体外培养后 ,培养上清中细胞因子分泌的水平 ,以反映HCV患者体内的免疫状况。方法 :患者PBMC培养上清中的细胞因子 (IL 2、IL 4、IL 10、IL 12、TNF γ、TNF α)采用ELISA进行检测。结果 :(1)HCV感染患者的PBMC培养 72h后 ,细胞因子检测结果表明 :与正常对照组相比较 ,HCV患者PBMC培养上清中TNF γ、IL 10和TNF α的水平明显升高 ,而没有检测到IL 2、IL 4、和IL 12的分泌产物。 (2 )轻、中度慢性肝炎 ,以及代偿期、失代偿期肝硬化患者间细胞因子的水平未见明显差异。结论 :(1)HCV感染患者体内细胞因子的分泌倾向于Th2型细胞因子占优势。 (2 )HCV感染患者PBMC分泌IL 2水平的降低可能是HCV免疫逃逸的原因之一     

Changes of cytokines in mice immunized with recombinant Bb-EmII/3-Em14-3-3 vaccine of Echinococcus multilocularis

AIM: To study the effects of recombinant Bb-EmII/3-Em14-3-3 vaccine on cytokine secretion in mice challenged with protoscoleces of Echinococcus multilocularis. METHODS: BALB/c mice were immunized with rBb-EmII/3-Em14-3-3 vaccine by subcutaneous injection, intramuscular injection, nasal mucosa inoculation or oral administration. After 12 weeks of immunization,all the mice were challenged with 50 protoscoleces of Echinococcus multilocularis by intraperitoneal injection. 18 weeks later, the mice were sacrificed and the splenocytes were stimulated with EmAg and ConA or LPS in vitro, then IL-12, IL-10, IFN-gamma and TNF-alpha in the culture supernatant were measured by ELISA. RESULTS: The level of IFN-gamma, IL-12 and TNF-alpha were greatly higher than that of PBS control group (P<0.05 or P<0.01), and the level of IL-10 was lower. The level of IFN-gamma, IL-12, TNF-alpha and IL-10 in each group with EmAg and ConA or LPS stimulation was greatly higher than that in the group without stimulation(P<0.05 or P<0.01). CONCLUSION: Th1 response is induced in mice challenged with Echinococcus multilocularis by rBb-EmII/3-Em14-3-3 vaccine, and the vaccine may enhance protective response against the challenge with protoscoleces of Echinococcus multilocularis.     

Combined effects of in vitro penicillin and sickle cell disease sera on normal lymphocyte functions

Previously published work has shown that sera from healthy sickle cell disease (SCD) patients inhibits normal lymphocyte response to phytohemagglutinin (PHA) in vitro. The objective of the current study is to ascertain what the combined effects of SCD sera plus penicillin have on normal lymphocyte cytokine production and mitogenic response to PHA. Steady state sera from 20 SCD patients not on penicillin prophylaxis and 20 comparable healthy controls were used in all experiments. Four normal healthy individuals were used as donors for obtaining peripheral blood mononuclear cells (PBMC), by density gradient. PBMC with or without penicillin were PHA stimulated by standard in vitro culture for mitogenic response and cytokine production. Supernatant cytokine levels for interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha and interleukin (IL)2 were quantified by ELISA technique. Results revealed suppression of mitogenic response in the SCD group with or without penicillin, compared to control sera (P < .001). Cytokine production in the SCD sera group showed increased production of IFN-gamma and TNF-alpha in the absence of penicillin, but suppression at all doses of penicillin. The control group results were as follows: no significant difference in IFN-gamma production with or without penicillin, mean TNF-alpha levels were the opposite of SCD sera with lower levels in the absence of penicillin. IL-2 production demonstrated a similar pattern for both groups of sera. IL-2 production was low without penicillin, but there was increased production with penicillin, which appeared dose related. The data suggests that sera from healthy SCD patients and in vitro added penicillin may have a combined suppressive effect on normal lymphocyte in vitro production of IFN-gamma and TNF-alpha. The current study results suggest that penicillin has the beneficial effect of decreasing TNF-alpha production and increasing IL-2 production when combined with SCD steady state sera. However, this in vitro benefit must be weighed against suppression of IFN-gamma production and ultimately, perhaps the long-term utility of penicillin prophylaxis in patients with SCD.     

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。     

Modulation of IL-2, IFN-gamma, TNF-alpha and IL-4 production in mice of different ages by thymopentin.

The effect of an immunomodulator drug thymopentin (TP5) on the production of various cytokines (IFN-gamma, IL-2, IL-4, TNF-alpha) in mice of different ages has been studied. TP5 enhanced IL-2, TNF-alpha and IFN-gamma production but reduced the IL-4 secretion by splenocytes from aged mice (greater than 120 week old) in vitro. However, it had no effect on the IL-2, IFN-gamma, TNF-alpha or IL-4 production by splenocytes from young and adult mice. TP5 injected subcutaneously was able to induce high levels of IL-2 production by splenocytes from all groups of mice. The TP5 effect on TNF-alpha and IFN-gamma was similar, even though it was significant only in old mice. Furthermore, TP5 was able to significantly reduce IL-4 production in old mice, which normally produced high levels of this cytokine after mitogen stimulation. Since it has been observed in the mouse that the Th1 cells secrete IFN-gamma and IL-2, whereas the Th2 cells preferentially produce IL-3, IL-4 and IL-5, these results indicate that the immunopotentiatory activity of TP5 is due to the preferential up-regulation of Th1 cells.     

Cytokine levels in patients with brucellosis and their relations with the treatment

PURPOSE: To determine the serum levels of proinflammatory and some of the Th1/Th2 cytokines in brucellosis and their alterations with treatment and outcome. METHODS: Twenty-eight acute and seven subacute brucellosis patients diagnosed clinically were included in the study. Twenty healthy volunteers were also included. Brucella standard tube agglutination tests and blood culture were conducted on all subjects. Cytokine levels of pre- and post-treatment period serum samples were measured by ELISA. RESULTS: The mean serum levels of IL-6, IFN-gamma and TNF-alpha were significantly higher in brucellosis patients compared to the control group ( P < 0.05). No significant differences were found between patient and control groups in terms of IL-1beta , TGF-beta 1, IL-2, IL-4 and IL-8 levels. There was a positive correlation between IFN-gamma, TNF-alpha and IL-6 levels with CRP levels. IL-6, IFN-gamma and TNF-alpha levels measured after treatment were statistically significantly lower than pre-treatment values ( P < 0.001). No differences were found in the levels of these cytokines between acute and subacute patients' sera. IL-6, IFN-gamma and TNF-alpha levels were higher in acute or subacute brucellosis patients. CONCLUSIONS: Although the levels of the cytokines were decreased significantly with effective and adequate treatment these alterations did not correlate with the extent or activity of the disease.     

Th1 cytokines and the prothrombinase fgl2 in stress-triggered and inflammatory abortion

PROBLEM: The immune system contributes to the outcome of pregnancy by complex immunological interactions. Cytokines especially influence the immune milieu pro or contra pregnancy. T helper 1 (Th1) cytokines [tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma)] cause inflammation and together are thought to threaten the maintenance of pregnancy. It has been proposed that increased levels of these Th1 cytokines activate coagulation via up-regulating the novel prothrombinase, fgl2. This study further investigates the Th1 cytokine up-regulation of fgl2 expression in a pathophysiological, stress induced abortion model, and an inflammatory, interleukin-12 (IL-12) triggered abortion model. METHOD: The DBA/2J-mated CBA/J female mice were exposed to sonic sound stress or were injected with IL-12 during early gestation. On day 13.5 of pregnancy the uteri were removed and the resorption rate was calculated. We evaluated TNF-alpha, IFN-gamma, fgl2 as well as IL-12 messenger RNA (mRNA) expression in decidual samples of all mice by quantitative, real-time polymerase chain reaction (PCR). RESULTS: A similar resorption rate of 24% was detected in stressed mice, as well as in IL-12 injected mice compared with approximately 11% in non-stressed, non-injected control mice. In stressed mice compared with controls, we observed on day 13.5 up-regulated TNF-alpha, unchanged IFN-gamma down-regulated fgl2, and a slightly increased levels of IL-12. In the IL-12 triggered abortion model, we observed up-regulated levels of TNF-alpha, IFN-gamma and fgl2. CONCLUSION: These novel data suggest two distinct cytokine patterns leading to similar abortion rates. A physiological cascade associated with up-regulation of TNF-alpha, and an IL-12-triggered cascade characterized by persistent up-regulation of TNF-alpha and IFN-gamma as well as a persistent increase in fgl2.     

Elevated levels of interferon-gamma, interleukin-10, and interleukin-6 during active disease in Indian kala azar

We have evaluated levels of 6 cytokines in sera of 35 patients of kala azar (KA), 29 post kala azar dermal leishmaniasis (PKDL), and 18 healthy controls using cytometric bead array technology. Results indicated significantly high levels of interferon gamma (IFN-gamma), interleukin (IL)-10, and IL-6 during active KA, while tumor necrosis factor alpha (TNF-alpha), IL-2, and IL-4 were minimal. Serum level of cytokines in PKDL was comparable to the controls while TNF-alpha was significantly elevated compared to KA or control. At post-treatment stage, KA patients showed a significant decrement in the levels of IFN-gamma, IL-10, and IL-6; however, IL-6 remained significantly elevated above control levels. Further, comparison of cytokine levels in children and adults revealed elevated level of IL-10 in pediatric cases. SAG unresponsive cases showed significantly elevated levels of IFN-gamma in comparison with the responsive cases. The results depict that type1 response is not depressed during active KA and suggest the possibility that unresponsiveness to type1 stimuli may prevail.     

Tumor necrosis factor alpha and interleukin-12 contribute to resistance to the intracellular bacterium Brucella abortus by different mechanisms.

Both interleukin-12 (IL-12) and tumor necrosis factor alpha (TNF-alpha) are produced early in intracellular bacterial infection. Depletion of either IL-12 or TNF-alpha by a single injection of specific antibody 4 h before the injection of Brucella abortus 19 led to the exacerbation of infection 2 weeks later. Whereas the effect of IL-12 depletion on resistance was persistent and exacerbation was still significant 6 weeks later, the bacterial numbers in mice depleted of TNF-alpha were similar to the bacterial numbers in control infected mice by 6 weeks postinfection. Massive splenomegaly, which is often seen in 2-week Brucella-infected mice, was not observed in IL-12- or TNF-alpha-depleted mice. Both IL-12- and TNF-alpha-depleted mice showed reduced cell accumulation in the spleen compared with the massive cell accumulation in control infected mice. Granuloma formation in livers was much reduced in IL-12-depleted mice but not in TNF-alpha-depleted mice. Gamma interferon (IFN-gamma) production by cells from TNF-alpha-depleted mice was not significantly different from that of cells from control infected mice. In contrast, the production of IFN-gamma by both CD4+ and CD8+ T cells from IL-12-depleted mice was greatly reduced, compared with that from control infected mice. This effect was still observed when the antibody injection was delayed for up to 7 days postinfection, but injections of anti-IL-12 antibody into mice with established Brucella infection had no significant effect on IFN-gamma production by T cells. Taken together, these results suggested that IL-12 contributed to resistance mainly via an IFN-gamma-dependent pathway and had a profound effect on the induction of acquired cellular resistance. In contrast, TNF-alpha was involved in resistance possibly via direct action on effector cells and may not be essential for the induction of acquired cellular resistance.     

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.