霉酚酸及其衍生物对人T淋巴细胞及混合淋巴细胞免疫应答的影响

目的探讨霉酚酸及霉酚酸衍生物对人T淋巴细胞和混合淋巴细胞免疫应答的影响。方法从正常人外周血中分离单个核淋巴细胞(PBMC),在抗CD3刺激下和混合淋巴细胞反应体系中,加入或不加霉酚酸及其衍生物共培养,应用ELISA和流式细胞术检测CD4+和CD8+T细胞细胞因子的产生、细胞活化和增殖情况。结果经抗CD3刺激后,PBMC产生的细胞因子明显增加,加入霉酚酸及其衍生物后,IFN-γ及TNF-α明显降低,IL-2产生略有增加。在混和淋巴细胞反应体系中,3种细胞因子产生皆被抑制。抗CD3刺激和混和淋巴细胞反应后,T细胞表面活化分子CD25及CD69表达增加,加入霉酚酸及其衍生物共培养24、48 h后,T细胞CD25及CD69的表达并未被抑制。霉酚酸及其衍生物可抑制抗CD3刺激下和混和淋巴细胞反应后T细胞的增殖。结论霉酚酸及其衍生物对T淋巴细胞和混合淋巴细胞体系中因子的产生和细胞增殖都有抑制作用,为其在临床自身免疫疾病及移植排斥中的广泛应用提供了理论依据。     

IL-12对BALB/c小鼠Th17细胞的分化的影响

目的: 观察细胞因子IL-12对Th17细胞分化的影响.方法: 小鼠脾淋巴细胞经抗CD3单克隆抗体(mAb)和不同浓度的重组小鼠IL-12刺激, 3 d后使用ELISA方法观察培养物上清液中IL-17的产生情况.并使用细胞内细胞因子染色的方法, 通过流式细胞术观察CD3 mAb和重组小鼠IL-12刺激对Th1和Th17细胞分化的影响.结果: Th17细胞不分泌IFN-γ、 IL-5、 IL-10等细胞因子, 不表达Foxp3, 是一个独立的细胞亚群.不同浓度的重组小鼠IL-12可以诱导抗CD3 mAb 的T细胞分泌IFN-γ, 并向Th1细胞方向分化.同时, IL-12可以抑制活化的T细胞分泌IL-17, 抑制T细胞向Th17细胞分化.结论: IL-12可以抑制Th17细胞的分化.     

HDAC抑制剂丙戊酸对小鼠T淋巴细胞表达细胞因子的影响

目的分析组蛋白去乙酰化酶(HDAC)抑制剂丙戊酸(Valproic acid,VPA)对小鼠T细胞亚群IL-2、IFN-γ和IL-6表达的影响,探讨其抗炎免疫调节作用的机制。方法经VPA处理小鼠淋巴细胞,并在佛波醇酯(PDB)和离子霉素刺激后,以流式细胞术分析CD3+、CD4+和CD8+T细胞表达IL-2、IFN-γ和IL-6的情况。结果淋巴细胞受刺激后,IL-6的表达水平仅稍有提高,而IL-2在CD4+和CD8+T细胞表达率分别为35.49%和5.50%,IFN-γ表达率分别为3.47%和38.60%。经VPA处理后,CD3+T细胞IL-6+、IFN-γ+和IL-6+IFN-γ+的表达均受剂量依赖性抑制(P<0.01)。同样,VPA能够剂量依赖性地降低小鼠CD4+和CD8+T细胞亚群内表达IL-2+、IFN-γ+的细胞比例(P<0.01),对于IL-2+IFN-γ+双阳性细胞的比例也具有明显抑制作用(P<0.01);此外,VPA对CD8+T细胞表达IFN-γ的抑制程度高于CD4+T细胞。结论 HDAC抑制剂VPA通过抑制IL-2和IFN-γ而发挥其抗炎和免疫调节效应。     

环孢素A对小鼠脾细胞IFN-γ产生的影响

目的研究在不同刺激条件下,环孢素A(CsA)对小鼠γ-干扰素(IFN-γ)产生的影响。方法小鼠脾淋巴细胞分别使用抗CD3单克隆抗体(mAb)、抗CD3mAb 抗CD28mAb及抗CD3mAb rIL-12刺激后,用ELISA法检测CsA对小鼠脾细胞IFN-γ产生的影响。在单个细胞水平上,用流式细胞仪检测CsA对脾细胞表面CD25和CD69表达及IFN-γ产生的影响。结果CsA对不同条件下诱导的小鼠脾细胞IFN-γ产生,均表现为剂量依赖性的抑制作用,其抑制机制与细胞的活化有关。结论CsA可以剂量依赖的方式抑制小鼠脾细胞表达CD25、CD69及产生IFN-γ。     

体外CD134L单抗或CTLA4Ig对狼疮样BXSB小鼠脾细胞分泌IL-6、IFN-γ及自身抗体的影响

目的:探讨体外CD134L单抗或CTLA4Ig对狼疮样BXSB小鼠脾细胞分泌IL-6、IFN-γ及自身抗体的影响。方法:采用未经治疗的狼疮样BXSB小鼠模型,应用CD134L单抗和/或CTLA4Ig体外特异性阻断CD134-CD134L或B7-CD28通路后,用MTT法测定分裂原刀豆蛋白A(ConA)诱导的脾淋巴细胞增殖反应和用ELISA方法测定ConA诱导的脾细胞培养上清液中IL-6、IFN-γ和抗ds-DNA抗体的表达水平,并与经中药狼疮方或强的松治疗的狼疮样BXSB小鼠模型进行比较。结果: (1)在单纯培养或经ConA刺激后培养,相比于正常对照鼠,狼疮样小鼠脾淋巴细胞都表现有增殖反应性的显著增高,IFN-γ、 IL-6蛋白量的增高和抗ds-DNA抗体的过度分泌。(2)经强的松或中药狼疮方体内治疗后,狼疮样小鼠脾淋巴细胞体外培养的增殖反应性及IFN-γ、IL-6的分泌都受到明显抑制,抗ds-DNA抗体的产生也明显减少。(3)体外单独应用CD134L单抗或 CTLA4Ig特异性阻断CD134-CD134L或B7-CD28共刺激信号通路,同样可以显著抑制体外培养的狼疮样小鼠脾淋巴细胞的增殖反应及IFN-γ、IL-6的分泌,并可明显减少抗ds-DNA抗体的产生,但它们的抑制作用比强的松、中药狼疮方体内治疗狼疮样小鼠时所表现出的类似效应要弱。(4)联合CD134L单抗和CTLA4Ig,则治疗作用显著提高,其抑制脾淋巴细胞的增殖反应及 IFN-γ、IL-6的分泌,抗ds-DNA抗体产生的作用都优于中药狼疮方的体内治疗效果,而与强的松的体内治疗效应相当。结论: CD134-CD134L可以提供独立的、非B7-CD28依赖的,另一种驱动抗原特异性T细胞增殖的协同刺激通路。同时阻断B7与 CD28、CD134L与CD134间的相互作用,使自身反应性T淋巴细胞的活化和增殖受到快速而最大限度的抑制,对治疗SLE等自身免疫性疾病可能是一种较理想的免疫干预模式。     

CpG-ODN联合抗CD40抗体活化小鼠调节性B细胞抑制CD4+T细胞增殖

目的分析CpG寡脱氧核苷酸(CpG-ODN)联合抗CD40抗体刺激后的调节性B细胞(Breg)对其免疫调节功能的影响。方法用流式细胞分选仪分选小鼠脾脏CD5+CD1 dhighBreg与CD5-CD1 dlowB细胞亚群,CpG-ODN联合抗CD40抗体激活24 h,再与纯化的CD4+T细胞共培养,流式细胞术检测活化后的Breg及对照CD5-CD1 dlowB细胞亚群白细胞介素10(IL-10)的表达,以及共培养抗CD3抗体联合抗CD28抗体激活的CD4+T细胞的增殖与γ干扰素(IFN-γ)的水平。结果 CpG-ODN联合抗CD40抗体激活的CD5+CD1 dhighBreg亚群与CD4+T细胞共培养时能明显抑制活化的CD4+T细胞的增殖,同时IFN-γ的水平降低;而CpG-ODN联合抗CD40抗体刺激后的对照B细胞亚群则不能抑制CD4+T细胞的增殖与IFN-γ分泌。CD5+CD1 dhigh Breg亚群在CpG-ODN联合抗CD40抗体刺激24 h,IL-10的表达水平明显高于CD5-CD1 dlowB细胞亚群。结论体外CpG-ODN联合抗CD40抗体刺激后的CD5+CD1 dhighBreg亚群通过分泌IL-10抑制CD4+T细胞的活化。     

阻断CD40-CD40L共刺激途径对T细胞表型及细胞因子分泌的作用研究

目的探讨应用抗CD40L单克隆抗体阻断CD40-CD40L共刺激途径后对T细胞表型及其分泌的细胞因子的影响,为体外阻断该共刺激途径诱导T细胞对异体移植抗原的免疫耐受提供实验依据.方法供鼠(C57BL/6H-2b)脾T细胞作为反应细胞,受鼠(BALB/CH-2d)脾细胞作为刺激细胞,设单抗组(加抗CD40L单抗)和对照组(不加单抗),初次混合淋巴细胞培养(MLR)7天,在不同时间点采用3H-TdR掺入法检测细胞增殖率,以ELISA法测定培养上清液中IFN-γ、IL-2、IL-4、IL-10等的水平,第5天采用流式细胞仪检测CD4+T和CD8+T细胞上CD25、CD69、CD40L和CD45RA的表达.再次MLR 5天,第1、3、5天采用3H-TdR掺入法测定细胞的增殖情况和ELISA法测定培养上清液中的上述细胞因子的水平.结果初次和再次MLR结果均显示,单抗组细胞增殖反应率明显低于对照组.初次MLR单抗组中CD4+T和CD8+T细胞比例明显低于对照组(P＜0.05);单抗组中CD4+CD25+T、CD4+CD69+T、CD8+CD25+T、 CD4+CD40L+T和CD8+CD69+T细胞比例明显低于对照组(P＜0.05),而CD8+CD40L+T和CD4+CD45RA+T细胞的比例与对照组相比无明显差异(P＞0.05).初次MLR中单抗组和对照组培养上清中IL-4和IL-10几乎无法测出,而单抗组培养上清中IFN-γ和IL-2的水平均明显低于对照组(P＜0.01);再次MLR后培养上清中单抗组IFN-γ、IL-2和IL-4和IL-10的分泌水平明显低于对照组(P＜0.05),但处于低水平,仍明显低于对照组.结论在体外MLR体系中,应用抗CD40L单抗孵育供鼠脾T细胞,可同时作用于CD4+T和CD8+T细胞,使CD40L+,CD25+和CD69+表达下降,引起T细胞早期的活化和成熟障碍,T细胞增殖能力减低,抑制了Th1类细胞因子IFN-γ和IL-2及Th2类细胞因子IL-4和IL-10的分泌水平,可诱导供者T细胞免疫耐受.     

环孢素A对LPS诱导的早期炎症反应的影响

目的研究环孢素A(cyclosporin A,CsA)对脂多糖(lipopolysaccharide,LPS)诱导的小鼠早期炎症反应的影响。方法小鼠腹腔内注射LPS诱导炎症反应,静脉注射不同浓度的CsA。6h后取血清,使用ELISA方法观察炎性因子IFN-γ和IL-6的含量;取脾细胞,使用流式细胞仪观察CD4+和CD8+T细胞表面的活化分子CD69表达;并使用细胞内细胞因子染色的方法,观察CD4+和CD8+T细胞IFN-γ和IL-4的产生水平。结果 CsA可以明显降低LPS诱导的小鼠血清中IFN-γ的水平,抑制CD4+和CD8+T细胞表面CD69分子的表达,抑制T细胞IFN-γ和IL-4的产生,均表现为剂量依赖性抑制关系。结论 CsA剂量依赖性抑制LPS诱导的小鼠早期炎症反应。     

葫芦素B对小鼠淋巴细胞活化、增殖和凋亡的影响

目的分析葫芦素B(CuB)对多克隆丝裂原激活的小鼠淋巴细胞活化、增殖、凋亡和γ-干扰素(IFN-γ)表达的影响,探讨其免疫调节作用的机制。方法经CuB处理的小鼠淋巴细胞,在刀豆蛋白(ConA,5μg/ml)或者佛波醇酯(PDB,10-7 mol/L)和离子霉素(Ion,0.5μg/ml)刺激后,细胞计数观察CuB对小鼠淋巴细胞增殖的抑制作用;流式细胞术分析CD69和IFN-γ的表达及亚二倍体峰和线粒体膜电位的变化;免疫印迹分析Caspase 3的活化水平。结果细胞计数分析显示,CuB对小鼠淋巴细胞增殖的抑制呈剂量依赖关系。对细胞DNA含量分析表明,随着CuB浓度的增加,处于亚二倍体峰(即凋亡峰)的细胞数量增加。同样,经CuB处理后,早期活化标志CD69和IFN-γ在CD3+T细胞中的表达均受剂量依赖性抑制。JC-1染色结果表明,10μmol/L CuB能显著使小鼠淋巴细胞的线粒体膜电位发生下降(P<0.01)。免疫印迹分析表明,10μmol/L CuB处理24 h后,Caspase 3明显活化。结论 CuB对小鼠淋巴细胞的增殖和活化具有明显抑制作,可以诱导体外培养的小鼠淋巴细胞发生凋亡,具有潜在的抗炎免疫调节活性。     

IL-12有助于化疗药物处理后肿瘤患者及小鼠的细胞免疫功能重建

目的探讨白细胞介素12(IL-12)是否能够恢复化疗药物对肿瘤患者和小鼠细胞的免疫抑制作用。方法分离顺铂化疗前后肿瘤患者及正常人外周血单个核细胞(PBMC),在抗CD3抗体和抗CD28抗体共刺激条件下,加或不加IL-12。培养后,ELISA检测上清中γ干扰素(IFN-γ)和肿瘤坏死因子α(TNF-α)的水平,流式细胞术检测不同亚群T细胞IFN-γ的水平。建立顺铂毒性小鼠模型,采用以上方法检测IFN-γ、TNF-α水平。结果肿瘤患者产生的IFN-γ和TNF-α显著低于正常人;与化疗前患者相比,化疗后患者IFN-γ和TNF-α的产生明显减少,IL-12可以显著增强IFN-γ和TNF-α的产生;T细胞亚群分析的结果表明,IL-12可以恢复化疗后CD4~+T细胞和CD8~+T细胞中IFN-γ的水平。小鼠体内实验证明,化疗药物抑制小鼠T细胞的免疫功能,IL-12能完全恢复T细胞免疫功能。结论化疗药物抑制肿瘤患者和小鼠细胞的免疫应答,而IL-12能够恢复化疗药物对细胞因子的抑制作用,从而对肿瘤化疗患者重建免疫功能起到非常重要的作用。     

The interleukin-12 subunit p40 specifically inhibits effects of the interleukin-12 heterodimer

The recently discovered cytokine interleukin (IL)-12 is a heterodimeric protein of two disulfide-bonded subunits of 35 and 40 kDa. IL-12 has multiple effects on T cells and natural killer (NK) cells. In particular it appears to be a major factor for the development of cellular immunity. So far activity of the single subunits alone has not been described, however their expression is regulated independently. In this report we demonstrate for the first time that the mouse IL-12 subunit p40 (IL-12p40) specifically antagonizes the effects of the IL-12 heterodimer in different assay systems. The proliferation of mouse splenocytes activated by phorbol ester and IL-12 was inhibited by IL-12p40, whereas the proliferation induced by phorbol ester and IL-2 was not affected. Furthermore, the synthesis of interferon (IFN)-γ by mouse splenocytes activated with IL-2 and IL-12 was suppressed by IL-12p40. Purified mouse splenic CD4⁺ T cells produced IFN-γ upon activation with plate-bound anti-CD3 monoclonal antibody which was enhanced more than tenfold in the presence of IL-12. In this system IL-12p40 inhibited only the enhancement caused by IL-12 but not IFN-γ synthesis of CD4⁺ T cells stimulated with anti-CD3 alone. Moreover, IL-12p40 inhibited the effects of IL-12 on differentiated T helper type 1 (T_h1) cells. IFN-γ production by T_h1 cells induced in a T cell receptor-independent way by macrophages and IL-2 or macrophages and IL-12 was greatly reduced by IL-12p40 providing evidence for the endogenous synthesis of IL-12 in the Th1 cell, macrophage and IL-2 co-cultures. The specificity of inhibition was clearly demonstrated in the homotypic aggregation assay of Th1 cells. Incubation of Th1 cells with either IL-2 and IL-12 or IL-2 and tumor necrosis factor induces LFA-1/ICAM-1-dependent aggregation. Only IL-2 + IL-12 but not IL-2 + tumor necrosis factor-induced aggregation was inhibited in a dose-dependent manner by IL-12p40. Thus, the IL-12 subunit p40 appears to be a specific inhibitor for the IL-12 heterodimer.     

Standardization and performance evaluation of mononuclear cell cytokine secretion assays in a multicenter study

Background

Burkholderia pseudomalleiis the causative agent for melioidosis. For many bacterial infections, cytokine dysregulation is one of the contributing factors to the severe clinical outcomes in the susceptible hosts. The C57BL/6 and BALB/c mice have been established as a differential model of susceptibility in murine melioidosis. In this study, we compared the innate IFN-γ response toB. pseudomalleibetween the C57BL/6 and BALB/c splenocytes and characterized the hyperproduction of IFN-γ in the relatively susceptible BALB/c micein vitro.

Results

Naïve BALB/c splenocytes were found to produce more IFN-γ in response to live bacterial infection compared to C57BL/6 splenocytes. Natural killer cells were found to be the major producers of IFN-γ, while T cells and Gr-1^intermediatecells also contributed to the IFN-γ response. Although anti-Gr-1 depletion substantially reduced the IFN-γ response, this was not due to the contribution of Gr-1^high, Ly-6G expressing neutrophils. We found no differences in the cell types making IFN-γ between BALB/c and C57BL/6 splenocytes. Although IL-12 is essential for the IFN-γ response, BALB/c and C57BL/6 splenocytes made similar amounts of IL-12 after infection. However, BALB/c splenocytes produced higher proinflammatory cytokines such as IL-1β, TNF-α, IL-6, IL-18 than C57BL/6 splenocytes after infection withB. pseudomallei.

Conclusion

Higher percentages of Gr-1 expressing NK and T cells, poorer ability in controlling bacteria growth, and higher IL-18 could be the factors contributing to IFN-γ hyperproduction in BALB/c mice.     

IL-4-producing NK T cells are biased towards IFN-γ production by IL-12. Influence of the microenvironment on the functional capacities of NK T cells

NK T cells are an unusual T lymphocyte subset capable of promptly producing several cytokines after stimulation, in particular IL-4, thus suggesting their influence in Th2 lineage commitment. In this study we demonstrate that, according to the cytokines present in the micro environment, NK T lymphocytes can preferentially produce either IL-4 or IFN-γ. In agreement with our previous reports showing that their IL-4-producing capacity is strikingly dependent on IL-7, CD4⁻ CD8⁻ TCRα β⁺ NK T lymphocytes, obtained after expansion with IL-1 plus granulocyte-macrophage colony-stimulating factor, produced almost undetectable amounts of IL-4 or IFN-γ in response to TCR/CD3 cross-linking. However, the capacity of these T cells to produce IFN-γ is strikingly enhanced when IL-12 is added either during their expansion or the anti-CD3 stimulation, while IL-4 secretion is always absent. A similar effect of IL-12 on IFN-γ production was observed when NK T lymphocytes were obtained after expansion with IL-7. It is noteworthy that whatever cytokines are used for their expansion, IL-12 stimulation, in the absence of TCR/CD3 cross-linking, promotes consistent IFN-γ secretion by NK T cells without detectable IL-4 production. Experiments in vivo demonstrated a significant up-regulation of the capacity of NK T cells to produce IFN-γ after anti-CD3 mAb injection when mice were previously treated with IL-12. In conclusion, we provide evidence that the functional capacities of NK T cells, which ultimately will determine their physiological roles, are strikingly dependent on the cytokines present in their microenvironment.     

Anti-IL-12 antibody prevents the development and progression of collagen-induced arthritis in IFN-γ receptor-deficient mice

In several models of inflammation, including collagen-induced arthritis (CIA), the disease-promoting effect of IL-12 has been attributed to its well-known ability to produce IFN-γ. However, IFN-γ receptor knockout (IFN-γ R KO) mice of the DBA/1 strain have been reported to be more susceptible to CIA than corresponding wild-type mice, indicating the existence of an IFN-γ-mediated protective pathway in this model. In the present study the development of CIA was found to be completely prevented by pretreatment with a neutralizing anti-IL-12 antibody, not only in wild-type, but significantly also in IFN-γ R KO mice. In both strains of mice, the protective effect of anti-IL-12 was associated with lower production of anti-collagen type II antibodies. In vivo stimulation with anti-CD3 antibody in arthritic IFN-γ R KO mice resulted in production of higher levels of circulating IFN-γ, TNF and IL-2 than in corresponding control mice that had not received the arthritis-inducing immunization. This was not the case in arthritis-developing wild-type mice. Furthermore, the protective effect of anti-IL-12 antibody in mutant, but not in wild-type mice, was associated with lower circulating IFN-γ, TNF and IL-2 and higher IL-4 and IL-5 cytokine levels following an anti-CD3 challenge. The data indicate that IL-12 promotes the development of arthritis independently of its ability to induce or favor production of IFN-γ. In fact, any IFN-γ produced in the course of the disease process rather exerts a protective effect. Furthermore, our study suggests that, in the absence of a functional IFN-γ system, endogenous IL-12 exerts its disease-promoting effect by favoring production of other Th1-associated cytokines (IL-2 and TNF), by inhibiting development of IL-4- and IL-5-producing T cells and by stimulating production of anti-collagen autoantibodies.     

瘦素(Leptin)与免疫系统的关系研究

为弄清高Leptin水平在不同免疫状态下对免疫系统的影响 ,选用 8周龄的清洁级BALB/c雄性小鼠共 4 0只 ,分成五组 ,分别用外源性鼠Leptin和Leptin抗体人为形成小鼠的不同Leptin水平状态 ,并利用CsA将小鼠分为正常免疫和免疫抑制状态两类 ,两种状态各设对照组 ,测定细胞增殖情况 ;用ELISA方法检测外周血和细胞培养液中IL 2、IL 4、IFN γ和Leptin的浓度。正常免疫状态下 ,Leptin组的脾细胞增殖与对照组无差异 ,细胞因子除IFN γ升高外 ,IL 2、IL 4均无差异 ;Leptin抗体组显示脾细胞增殖能力下降 ,各细胞因子测定示显示差异 ;免疫抑制状态下 ,Leptin组的细胞增殖活力较强 ,IL 2、IFN γ水平上升 ,IL 4分泌降低 ,这种结果也在几乎所有体外加入Leptin的各组中出现。表明Leptin可以起免疫调节作用 ,增加IFN γ、IL 2的合成 ,降低IL 4的产生 ,使免疫应答向Th1细胞方向偏离。在正常免疫状态下Leptin的调节作用不明显 ,而在免疫抑制情况下 ,这种调节作用可以得到体现。     

CD40/CD40 ligand interactions are required for T cell-dependent production of interleukin-12 by mouse macrophages

We have previously shown that T cell receptor-activated mouse T helper (Th)1 clones induce the production of interleukin (IL)-12 by splenic antigen-presenting cells (APC). Here, we show that the expression of CD40L by activated T cells is critical for T cell-dependent IL-12 production by mouse macrophages. IL-12 was produced in cultures containing alloreactive Th1 clones stimulated with allogeneic peritoneal macrophages, or in cultures of splenocytes stimulated with anti-CD3. Anti-CD40L monoclonal antibodies (mAb) inhibited the production of IL-12, but not IL-2, in these cultures by ?90% and had dramatic inhibitory effects on antigen-dependent proliferation of Th1 clones. In addition, both activated T cells and a Th1 clone derived from CD40L knockout mice failed to induce IL-12 production from splenic APC or peritoneal macrophages. Finally, macrophages cultured in the absence of T cells produced IL-12 upon stimulation with soluble recombinant CD40L in combination with either supernatants from activated Th1 clones or with interferon-γ and granulocyte/macrophage colony-stimulating factor. Thus, both CD40L-dependent and cytokine-mediated signals from activated T cells are required to induce the production of IL-12 by macrophages. A blockade at the level of IL-12 production may explain, at least in part, the dramatic ability of anti-CD40L mAb to inhibit disease in animal models that are dependent upon the generation of a cell-mediated immune response. Moreover, a defect in T cell-dependent induction of IL-12 may contribute to the immune status of humans that lack functional CD40L.     

八肽胆囊收缩素对经钥孔戚血蓝蛋白免疫小鼠T淋巴细胞亚群的影响

目的：探讨八肽胆囊收缩素（CCK-8）对经钥孔戚血蓝蛋白（KLH）免疫小鼠T淋巴细胞亚群的影响。方法：雌性BALB/c小鼠KLH免疫同时分别给予不同剂量CCK-8。流式细胞法检测小鼠外周血及脾细胞中CD4+、CD8+T细胞阳性百分率；RT-PCR法检测脾细胞中Th1型细胞因子IFN-γ、Th2型细胞因子IL-4 mRNA表达；ELISA法检测其培养上清中IFN-γ、IL-4水平；HE染色观察小鼠肺组织病理变化。结果：CCK-8下调KLH免疫小鼠外周血及脾细胞中上升的CD4+、CD8+T细胞阳性百分率，降低CD4+/CD8+比值；进一步提高其IFN-γ mRNA表达和培养上清中IFN-γ分泌量，同时下调上升的IL-4 mRNA表达和培养上清中IL-4分泌量；减轻KLH免疫所致小鼠肺部炎症。结论：CCK-8可调节适应性免疫应答，抑制T细胞尤其是CD4+T细胞活性；抑制Th2功能，提高Th1功能，因此可能在变态反应性疾病的发病和防治中具有一定作用。     

Production of IFN-γ by CD4(+) T cells in response to malaria antigens is IL-2 dependent

T-cell immune responses are critical for protection of the host and for disease pathogenesis during infection with Plasmodium species. We examined the regulation of CD4(+) T-cell cytokine responses during infection with Plasmodium berghei ANKA (PbA). CD4(+) T cells from PbA-infected mice produced IFN-γ, IL-4 and IL-10 in response to TCR stimulation at levels higher than those from uninfected mice. This altered cytokine response was dependent on parasitemia. To examine the specificity of the response, mice were adoptively transferred with CD4(+) T cells from OT-II TCR transgenic mice and were infected with PbA expressing OVA. Unexpectedly, CD4(+) T cells from the OT-II-transferred wild-type PbA-infected mice showed high levels of IFN-γ production after stimulation with OVA and the cells producing IFN-γ were not OT-II but were host CD4(+) T cells. Further investigation revealed that host CD4(+) T cells produced IFN-γ in response to IL-2 produced by activated OT-II cells. This IFN-γ response was completely inhibited by anti-CD25 mAbs, and this effect was not due to the block of the survival signals provided by IL-2. Furthermore, IFN-γ production by CD4(+) T cells in response to PbA antigens was dependent on IL-2. These findings suggest the importance of IL-2 levels during infection with malaria parasites and indicate that CD4(+) T cells can produce IFN-γ without TCR engagement via a bystander mechanism in response to IL-2 produced by other activated CD4(+) T cells.     

内源性IL-12决定人PBMC产生干扰素γ的水平

目的：IFN－γ是由被有丝分裂原或抗原所激活的T细胞和NK细胞所产生,它具有广泛的免疫调节活性,现认为IL－12（外源性）是诱导IFN－γ产生的强诱导剂,并可促进静息CD4^ T细胞朝向Th1表型分化,即诱导细胞免疫。目的是为了解PBMC产生的内源性IL－12是否在体外可诱导IFN－γ的产生及通过何机制诱导细胞免疫。方法：用抗CD3抗体、PHA、抗CD3抗体加抗CD28抗体和抗原（MLC）来检测被刺激的PBMC细胞的IFN－γ的产生。同时也用IL－12和IL－12Rβ1的中和抗体来抑制IFN－γ的产生。结果：活的人PBMC中IFN－γ分泌依赖于内源性IL－12的产生,而且激活的T细胞可诱导APC细胞产生IL－2,此过程是通过T细胞表面的CD40L和APC的CD40相互作用而实现。结论：这些结果显示,内源性IL－12在正常罕主抗细胞内抗原的感染反应中起重要作用,在某些形式的自身免疫性疾病和移植排斥反应的免疫病理发生中也起中心作用。