Increased plasma levels of soluble IL-2R are associated with severe Plasmodium falciparum malaria.

Plasma samples from children with mild and severe Plasmodium falciparum malaria and from children with unrelated diseases were collected to investigate whether the clinical outcome of infection was associated with plasma factors which reflected the activity of different cells of the immune system. Children with severe P. falciparum malaria had significantly higher plasma levels of soluble IL-2R than children with mild malaria. Plasma levels of IL-2R and levels of parasitaemia were significantly correlated. Neither parasitaemia nor plasma levels of tumour necrosis factor-alpha (TNF-alpha), IL-6, lymphotoxin (LT), interferon-gamma (IFN-gamma), IL-4, soluble IL-4R or soluble CD8 differed significantly between the two groups of children with malaria. High plasma levels of soluble CD8 were associated with failure of lymphocytes to produce IFN-gamma in vitro following stimulation with P. falciparum antigen. We conclude that soluble IL-2R is a useful marker of disease severity independently of the association with levels of parasitaemia, and that functional regulation of different lymphocyte subsets occurs during acute malaria episodes.     

Enhancement of IL-1, IL-2 production and IL-2 receptor generation in patients with acute rheumatic fever and active rheumatic heart disease; a prospective study.

In a prospective study, patients with quiescent rheumatic heart disease (CRHD), streptococcal pharyngitis (SP) and healthy normal subjects produced comparable amounts of IL-1 and IL-2, but acute rheumatic fever (ARF) patients produced significantly elevated amounts of IL-1 and IL-2 at all intervals up to 48 weeks. In active rheumatic heart disease (ARHD), IL-1 activity returned to within normal range at 48 weeks, but IL-2 activity remained persistently elevated compared with CRHD, SP and healthy age- and sex-matched volunteers. CD4+ T lymphocytes were significantly increased in the peripheral blood of ARF and ARHD patients. The amount of IL-2 produced by ARF and ARHD patients correlated with the percentage of helper T lymphocytes (CD4+ cells) but not with the percentage of suppressor/cytotoxic T lymphocytes (CD8+ cells). Moreover, pre- and post-phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear cell (PBMC) cultures from ARF and ARHD patients contained higher proportions of IL-2R+ (CD25+) cells than those from patients with SP, CRHD and normal individuals, which persisted up to 48 weeks. The percentage of CD25+ cells in both types of PBMC cultures directly correlated with the percentage of CD4+ cells and not with CD8+ cells in active rheumatic patients only. These findings indicate that the immune response in ARF and ARHD patients is skewed to produce activated helper T cells that release IL-2 which drives the accumulation of more T helper cells. The result is an undamped helper T cell response in the peripheral blood of these patients.     

High levels of circulating IL-10 in human malaria.

IL-10 is a monocyte/lymphocyte derived cytokine which has been shown to inhibit certain cellular immune responses such as delayed hypersensitivity. In particular, the production of tumour necrosis factor (TNF), IL-1 and IL-6, which are involved in malaria pathology, are strongly inhibited by IL-10. Accordingly, we examined whether IL-10 could be involved in a human acute parasitic infection such as Plasmodium falciparum malaria. Human IL-10 levels in plasma were determined by two-site ELISA method, taking care to avoid non-specific reactions due to autoantibodies. Fourteen cerebral, 11 severe, and 20 mild malaria cases had mean IL-10 levels of 2812, 2882 and 913 pg/ml, respectively, while 98% of healthy individuals had undetectable (less than 100 pg/ml) circulating IL-10. Thirteen of the 25 cerebral/severe cases had > 2000 pg/ml. In 11 hospitalized patients, circulating IL-10 levels were found to return to virtually normal levels 7 days after antimalarial chemotherapy when biological and clinical malaria features had disappeared (mean levels fell from 3880 to 333 pg/ml). Further studies are required to determine whether these elevated levels of IL-10 play a beneficial role by reducing the parasite-induced inflammatory response, or a detrimental one by decreasing the cellular immune responses.     

Soluble IL-2 receptor and tumour necrosis factor-alpha in plasma of haemophilia patients infected with HIV.

We measured plasma concentrations of soluble receptors for IL-2 (sIL-2R) and tumour necrosis factor-alpha (TNF-alpha) in 149 haemophilia patients. Soluble IL-2R levels were elevated in 37% of 62 HIV-seronegative patients (mean 570 +/- 27 U/ml versus 361 +/- 17 U/ml in the control group, P less than 0.0001), in 78% of 68 HIV-seropositive patients (928 +/- 49 U/ml, P less than 0.0001), and in 95% of 19 AIDS/ARC patients (1578 +/- 199 U/ml, P less than 0.0001 compared with controls and with HIV-seronegative patients; P less than 0.005 compared with HIV-seropositive asymptomatic patients). A negative correlation was observed between sIL-2R, relative and absolute numbers of CD4+ cells (P less than 0.0001), and CD4/CD8 ratios (P less than 0.0001). There was also a negative correlation between sIL-2R in plasma and the cellular expression of IL-2R (P less than 0.001). We found a significant association of sIL-2R and plasma neopterin (P less than 0.0001). With progression of the disease from HIV-seronegative to seropositive without symptoms and to full manifestation of AIDS/ARC, sIL-2R plasma levels increased. The highest levels were found at the time of diagnosis of AIDS/ARC, but the levels decreased again during the following 18 months. Eight per cent of HIV-seronegative patients, 32% of HIV-seropositive patients, and 24% of patients with AIDS/ARC had increased plasma TNF-alpha. We conclude that sIL-2R and TNF-alpha plasma levels are elevated in HIV-infected haemophilia patients and that sIL-2R is a marker for disease progression from asymptomatic HIV-seropositive to AIDS/ARC.     

Ligand binding kinetics of IL-2 and IL-15 to heteromers formed by extracellular domains of the three IL-2 receptor subunits

Studies on the binding of IL-2 to its receptor (IL-2R) havegenerally been limited to receptors expressed on cell surfaces.This has hampered detailed kinetic and mechanistic studies atthe molecular level. We have prepared the soluble extracellulardomains of all three receptor subunits (called , ßand ) by recombinant techniques and have used these to performdetailed kinetic studies of their binding properties using thetechnique of surface plasmon resonance. We describe a novelapproach whereby the receptors are assembled on an antibodysurface, being held by an epitope engineered into the C-terminusof each of these domains. Thus the receptors are oriented naturallyleading to homogeneous ligand binding kinetics. We have characterizedthe interactions of the heteromeric complexes of these subunitswith mouse and human IL-2 and their analogs, as well as therecently discovered cytokine, IL-15. We have also studied theextracellular domains of the mouse receptor subunits for thefirst time and have used these as well as mouse-human hybridreceptors to probe the mechanism of assembly of these complexes.We show that no additional proteins are required to reproducethe properties of these complexes in vitro. In addition, kineticstudies with site-specific analogs of IL-2 and the mouse-humanreceptor hybrids clearly indicate that the extracellular domainsof and ) can together readily bind ligand with kinetic propertiesdistinct from those of the constituent subunits. In contrast,a complex containing ligand and the extracellular domains of and ß was comparatively difficult to assemble andrequired prolonged exposure to IL-2. Our method enabled us tocalculate the stoichiometry of these complexes and to determinethat anchoring these subunits is necessary to efficiently drivecomplex formation. The kinetic and equilibrium differences betweenthe mouse and human receptor complexes, and between IL-2 andIL-15 binding to these receptors clarify the roles of the andß subunits in the differential response of cells todifferent cytokines that may be present simultaneously in theenvironment.     

Requirement of high-affinity IL-2-IL-2R interaction for T cell anergy induction

Incomplete T cell antigen receptor-mediated signaling induces an unresponsive state known as anergy. Previously, we had shown that anergy can be induced in antigen-primed but not naive T cells. In this report, we found that in vitro primed T cells from IL-2R alpha-deficient mice were resistant to anergy induction in contrast to comparably treated wild-type T cells. This resistance persisted even after proliferation of IL-2R alpha chain-deficient CD4 T cells with high-dose IL-2-IL-2R beta gamma chains interaction. Thus, antigen activation, and/or progression through cell cycle are not sufficient to induce anergy susceptibility in T cells. The high-affinity IL-2-IL-2R interaction appears to play a critical role in this process.     

Soluble IL-2 receptor levels in patients with Graves'' ophthalmopathy.

In various autoimmune diseases circulating levels of soluble IL-2 receptor (sIL-2R) seem to be related to disease activity. Because reliable parameters of disease activity in Graves' ophthalmopathy are lacking, we measured sIL-2R levels in 47 patients with this disorder. The patients had Graves' disease, but no other immune-mediated diseases, had not yet received specific treatment for their ophthalmopathy and were euthyroid during the entire study period. Twenty-one of the 47 patients (45%) had sIL-2R values above the upper normal limit of 650 U/ml, as established in 20 healthy controls. There were no differences between patients with normal (median 469, range 280-644 U/ml) and elevated (median 946, range 678-1588 U/ml) sIL-2R levels regarding duration or severity of the eye disease (as assessed clinically from the total eye score). However, patients with severely enlarged eye muscles had higher sIL-2R values than patients with less severely enlarged eye muscles on CT scan. Patients with elevated sIL-2R tended to have a higher response rate (71%) to a 3-month course of prednisone, than those with normal levels (46%; P = 0.081). Since a successful outcome of prednisone treatment might be representative for disease activity, the elevated sIL-2R levels seem to reflect active inflammation. Although the practical relevance of this finding in individual patients is limited, it underscores the importance of cell-mediated immune responses in this thyroid-related eye disease.     

IL-2 Family of Cytokines in T Regulatory Cell Development and Homeostasis

Introduction  Interleukin 2 (IL-2) induces an essential signal for T regulatory (Treg) cells. Without a functional IL-2R, only immature CD4⁺ Foxp3^low CD25^neg T cells develop, and these cells fail to suppress autoreactive T cells in the periphery. Discussion  IL-2 functions during Treg cell development by upregulating Foxp3 and CD25 and by increasing the number of thymic Treg cells. Upon exiting the thymus during neonatal life, IL-2 is responsible for rapid amplification of the number of Treg cells in peripheral lymph nodes to insure suppression of autoreactive T cells that escape negative selection, thereby maintaining tolerance. The homeostasis of Treg cells in mature immunocompetent mice also depends on IL-2. However, there is an alternative mechanism for Treg cells homeostasis that may represent a minor IL-2-independent pathway or the consequence of weak and very transient IL-2R signaling. Conclusion  Thus, IL-2 provides importance signals for Treg cell development and for their homeostasis in peripheral immune tissues.     

生物素-链霉亲和素系统在检测人PBMC IL-2R_α中的应用

本文报道用自制生物素-链霉亲和素系统配以抗IL-2R_aMcAb,建立检测人PBMCIL-2R_a的方法,并对本法中的关键条件进行探索,确定生物素化二抗和链霉亲和素的最适浓度以及多种诱导物的最适诱导时间和浓度。用本法对比检测了健康献血者和肿瘤患者PBMC IL-2R_a的表达水平,表明未经诱导的肿瘤患者PBMC IL-2R_a百分率显著高于正常人(P<0.01)。     

雷公藤单体T_4体外给药对IL－2R表达的影响

Ｔ_Ⅱ是中草药雷公藤的一类粗提物，临床治疗类风湿关节炎和系统性红斑狼疮等免疫性疾病效果显著。Ｔ_４是进一步从Ｔ_Ⅱ中提取出的单体成分。以正常人外周血单个核细胞（ＰＢＭＣ）为实验材料，测定了不同浓度的Ｔ_Ⅱ（０．０９８～３．１３Ｕ／ｍｌ）和Ｔ_４（０．０３９～５ｎｇ／ｍｌ）对于Ｔ细胞功能的影响。结果表明，Ｔ_Ⅱ和Ｔ_４对Ｔ细胞表面ＩＬ－２Ｒ的表达剂量相关的抑制作用。结果还显示，在药物作用下，ＩＬ－２对ＩＬ－２Ｒ表达的调节作用是很有限的。     

The significance of serum soluble IL-2 receptor as a marker for active visceral leishmaniasis in Sicilian patients.

Sera from nine Sicilian patients with confirmed visceral leishmaniasis (Leishmania donovani infantum; VL), at the moment of the diagnosis, during the course of the disease and after clinical recovery, were analysed for the concentration of soluble IL-2 receptor (sIL-2R). The results show that sIL-2R is a marker of disease activity, since it is in high concentration at the beginning of infection and returns to the normal range following successful chemotherapy. At the same time of serum analysis for sIL-2R, peripheral blood mononuclear cells (PBMC) of VL patients were stimulated with phytohaemagglutinin (PHA) or antigen and supernatant tested for IL-2 and interferon-gamma (IFN-gamma) production. Data demonstrate that there is an inverse relation between concentration of IL-2 and IFN-gamma in the supernatants and sIL-2R secretion in the sera.     

重组细胞分泌可溶性IL-2R的动态检测及放免分析

ELISA检测表明:重组CHO细胞产生的IL-2Rα分子主要分布在细胞膜上,少量分泌到膜外成为可溶性IL-2R(sIL-2R)。sIL-2R产生的时相与膜IL-2Rα相似,但后者有一个较长的高浓度稳定期。此结果提示:膜IL-2Ra代谢比培养液中sIL-2R明显活跃,但sIL-2R的水平并不随膜IL-2Rα含量增加而改变,sIL-2R这种恒定的代谢方式可能包含着独特的免疫生物学意义。放免受体分析表明:重组IL-2Rα的最大结合容量(Bmax)为33000/细胞,KD为1.5×10~(-11)M。大剂量IL-2才能阻断Wu69McAb与IL-2Rα的结合。提示:IL-2与Wu69 McAb结合IL-2Rα的位点虽然不同,但可能十分靠近。     

红细胞天然免疫分子CD59与可溶性IL-2R相关性分析

为了探讨红细胞CD5 9与可溶性IL 2受体 (sIL 2R )之间变化规律。采用流式细胞仪测定红细胞CD5 9,用ELISA法测定sIL 2R含量。结果发现肿瘤患者红细胞CD5 9数量 (平均荧光相对强度 5 2 5 8± 12 4 2 )明显低于 2 6例银屑病患者 ( 6 31 0 0±16 6 70 ,P <0 0 5 ) ,而 19例正常人sIL 2R含量 ( 1736 5 8± 6 5 0 10 )ng/L明显低于肿瘤患者 ( 2 36 4 80± 831 2 0 ,P <0 0 5 ) ,6 5例标本同时测定红细胞CD5 9和sIL 2R ,两者之间存在负相关 (r= 0 312 ,P <0 0 5 )。红细胞CD5 9与sIL 2R之间变化的分析为免疫反应的调控规律及临床提供了有用的信息     

IL-2 receptor subunit, p75: direct demonstration of its IL-2 binding ability by using a novel monoclonal antibody

A new monoclonal antibody (mAb), TU11 mAb, was found to be specific for the p75 subunit of human interleukin 2 receptor (IL-2R). TU11 mAb reacted with human and Gibbon ape cell lines positive for IL-2Rp75 but not with cell lines negative for IL-2Rp75 tested. TU11 mAb specifically detected a single cell surface molecule with a molecular weight of 75 kd. The 75 kd molecule was identical to p75 detected by TU27 mAb specific for human IL-2Rp75 in sequential immunoprecipitation. TU11 mAb did not block IL-2 binding to the high-affinity IL-2R at all and precipitated p75 bound with IL-2. Using TU11 mAb, we have demonstrated here that solubilized p75 has an IL-2 binding site.     

SLE患者淋巴细胞膜上IL-2R表达的动态分析

本实验采用Wu Tac单克隆抗体的间接荧光抗体法,动态观察了系统性红斑狼疮(SLE)患者和正常供血员(对照组)的外周血淋巴细胞经PHA刺激后,于不同时间(0、24、48、72小时)内细胞膜上白细胞介素2受体(IL-2R)的表达。结果表明在给予PHA刺激培养24、48和72小时后,与对照组比较SLE患者淋巴细胞的IL-2R表达明显下降,提示了SLE的T淋巴细胞反应性降低可能与被激活的T细胞表面IL-2R的表达功能缺陷有关。此结果将有助于进一步探讨SLE的免疫调节紊乱的发生机制。     

IL-2 regulation of soluble IL-2 receptor levels following thermal injury.

In the immunosuppressed burn patient serum levels of both IL-2 and a soluble form of IL-2 receptor alpha (sIL-2R alpha) are significantly elevated. Strikingly, the production of these markers by the in vitro activated patients' cells is decreased. This study examines the role of IL-2 in the decreased production of the sIL-2R alpha in vitro in patients with major burns (n = 18, 30 to greater than 70% total body surface area). Peripheral blood mononuclear cell (PBMC) cultures from patients with highly elevated serum sIL-2R alpha, and from healthy controls (n = 12) were activated with concanavalin A (Con A) at initiation. In patients' cultures mitogen-induced increments of sIL-2R alpha levels were significantly lower. There was a significant negative correlation (r = 0.64, P less than 0.001) between a high serum sIL-2R alpha level and a decreased lectin-induced sIL-2R alpha release in vitro. Low levels of sIL-2R alpha in patients' samples were not normalized by increasing the number of T lymphocytes. Also exogenous rIL-1 was without effect, whereas rIL-3 increased sIL-2R alpha release in some cultures. However, sIL-2R alpha levels were significantly increased in patients' cultures by (i) addition of exogenous IL-2; (ii) removal of adherent cells; (iii) addition of cyclooxygenase inhibitor, indomethacin; (iv) bypassing cell surface activation by the combination of the calcium ionophore A23187 and the phorbol ester 12-o-tetradecanoyl acetate. The cyclic AMP-elevating drug, forskolin, abrogated the ability of exogenous IL-2 to increase sIL-2R alpha production. Thus, in the burn patient, the reduced in vitro sIL-2R alpha release appears to relate to abnormalities in IL-2 production and action mediated through its functional surface receptor. Elevated levels of sIL-2R alpha in vivo may, therefore, reflect systemic activation of T lymphocytes in response to biologically active IL-2.     

Soluble IL-2 receptor and CD25 cells in psoriasis: effects of cyclosporin A and PUVA therapy.

A study was conducted to quantify soluble IL-2 receptor (sIL-2R) levels in sera of 57 chronic plaque psoriasis patients and correlate these measurements with disease activity and the number of IL-2R-positive (CD25+) lymphocytes in lesional biopsies of 11 cyclosporin A (CsA) and 13 psoralen plus ultraviolet radiation (PUVA) treated patients. Levels of sIL-2R showed a strong correlation with the psoriasis area and severity index (PASI). CsA and PUVA significantly reduced the PASI and sIL-2R levels to a similar degree after 4 weeks of treatment. Although the majority of CsA-treated patients who were biopsied showed reductions in lesional CD25+ cells, these did not reach statistical significance; in five patients biopsied who had PUVA treatment, no consistent effect on the numbers of CD25+ cells was observed. A significant correlation was found between CD25+ cells in lesional biopsies and the PASI score.     

新生儿脐血T细胞IL－2R表达和血清sIL－2R水平的研究

对新生儿脐血Ｔ细胞ＩＬ－２Ｒ表达率和血清ｓＩＬ－２Ｒ水平进行检测，结果显示：①早产儿脐血Ｔ细胞ＩＬ－２Ｒ自然表达率明显低于足月新生儿和正常儿童组，而后两者间无差异；②经ＰＨＡ活化后足月新生儿和早产儿Ｔ细胞ＩＬ－２Ｒ表达率皆显著低于正常儿童组，早产儿组也明显低于足月新生儿组；③足月新生儿和早产儿脐血血清ｓＩＬ－２Ｒ水平均明显高于正常儿童组，但前两者间无明显差异；④新生儿组（包括足月和早产儿）脐血Ｔ细胞ＩＬ－２Ｒ自然表达率与血清ｓＩＬ－２Ｒ水平呈直线负相关，而正常儿童组二者间呈直线正相关。     

虫草多糖对人外周血IL－2、IL－ZR及IFN－γ调节作用的研究

本研究观察了冬虫夏草多糖（ｃｏｒｄｙｃｅＰｓＰｏｌｙｓａｃｃｈｒｉｄｅ，ＣＰ）对体外培养的外周血淋巴细胞（ＰＢＬ）的ＩＬ－２、ＩＬ－２Ｒ、ＩＦＮ－γ的影响。结果表明，ＣＰ可单独或协同ＰＨＡ诱导ＩＬ－２Ｒ的表达，促进可溶性ＩＬ－２Ｒ（ｓＩＬ－２Ｒ）的生成，但对ＰＨＡ诱生的ＩＬ－２、ＩＦＮ－γ活性有选择性抑制作用。其协同或抑制作用均呈剂量依赖性，吲哚美辛可部分或全部消除其抑制效应。提示ＣＰ对体外培养的ＰＢＬ具有双向免疫调节作用。