逆转录病毒介导IL-18基因在大鼠胶质瘤细胞C6中的表达

目的 :建立表达IL 18基因的大鼠胶质瘤细胞C6 /IL 18,并探讨外源性IL 18基因对C6细胞生长的影响。方法 :应用逆转录病毒载体 ,将IL 18基因导入C6细胞。经G4 18筛选后 ,获得表达IL 18分子的细胞克隆C6 /IL 18。用RT PCR法检测目的基因mRNA的表达 ;用流式细胞和免疫细胞化学染色法检测目的蛋白的表达。用ELISA法检测C6 /IL 18细胞培养上清诱导脾细胞分泌IFN γ的能力 ,以确定IL 18的生物学活性。用MTT比色法检测细胞体外增殖的状况 ,用流式细胞技术检测细胞的增殖活性 ,并建立大鼠胶质瘤模型 ,观察C6 /IL 18细胞体内致瘤性的改变。结果 :外源IL 18基因于mRNA水平和蛋白水平可获得稳定表达 ,并可诱生大鼠脾细胞分泌IFN γ。同时 ,该细胞系的体外增殖率及体内致瘤性 ,均较亲代C6胶质瘤细胞明显下降。结论 :外源性IL 18基因能部分地抑制C6细胞的体外增殖率和体内致瘤性。建立了可进一步用于相关肿瘤基因免疫和基因治疗研究的大鼠胶质瘤细胞系C6 /IL 18。     

Increased IL-2, IL-4 and interferon-gamma (IFN-gamma) in steroid-sensitive nephrotic syndrome.

We investigated the production of cytokines by peripheral blood mononuclear cells (PBMC) and serum cytokine concentrations in children with steroid-sensitive idiopathic nephrotic syndrome (SSNS). PBMC from patients off treatment were collected during remission and relapse and cultured in medium alone or stimulated with calcium ionophore plus phorbol myristate acetate. Control PBMC were taken from healthy age-matched children. IL-2 was measured by bioassay, IL-4 by immunoradiometric assay, and IL-8 and IFN-gamma by ELISA. After 24 h culture without stimulation, IL-2, IL-4 and IFN-gamma were not detectable in the supernatant in any of the children. After stimulation, the supernatant concentrations of IL-2 (median 172 U/ml at 24 h) and IL-4 (160 pg/ml at 24 h; 210 pg/ml at 72 h) were significantly increased in relapse compared with remission (IL-2 37 U/ml; IL-4 65 pg/ml and 60 pg/ml) and controls (IL-2 69 U/ml; IL-4 40 pg/ml and 40 pg/ml) (P < 0.05). The concentration of IFN-gamma was not significantly increased in relapse compared with remission and controls (600, 325, and 145 U/ml, respectively, at 72 h). IL-8 concentrations were similar in relapse, remission and controls with stimulation (median 32, 40 and 40 ng/ml, respectively) and without (30, 17 and 10 ng/ml). IL-2 was not detectable in serum, but IL-4, IL-8 and IFN-gamma were measurable in about half the patients, both in relapse and remission, though were virtually undetectable in controls. We conclude that relapse of SSNS in children is associated with T lymphocyte activation with release of IL-2, IL-4 and IFN-gamma.     

Interferon-gamma inhibits the proliferation but not the differentiation of murine B cells in response to IL-5

Interferon-gamma (IFN-gamma) is supposed to be produced by type 1 helper T cells (TH1) and inhibits IL-4-dependent B cell growth and differentiation. IL-5 (T cell-replacing factor, TRF), is a T cell-derived lymphokine which is predominantly produced by type 2 helper T cells (TH2) and regulates proliferation and differentiation of activated B cells. In this study, the effect of IFN-gamma on IL-5-dependent B cell growth and differentiation has been studied using murine chronic B cell leukemic cells (BCL1), normal splenic B cells, and cloned early B cell line. IFN-gamma selectively inhibits the IL-5-mediated proliferation of activated B cells as well as cloned early B cell lines at a low concentration (2 U/ml) in which polyclonal IgM production was not affected. This inhibitory effect of IFN-gamma occurs within 24 h after the onset of culture, as demonstrated by the inability of antibody to IFN-gamma to reverse totally the IFN-gamma-mediated suppressive effects if it was added later than 24 h after the onset of the culture. On the contrary, IL-5-mediated IgM secretion of BCL1 and IgA formation of LPS-stimulated normal B cells were relatively resistant to the suppressive effect of IFN-gamma. IFN-gamma does not affect the receptor expression for IL-5. Interestingly, IL-4-mediated IgG1 formation of LPS-stimulated B cells was markedly suppressed by IFN-gamma at 10 U/ml. These results strongly suggest that IFN-gamma may have differential effects on IL-5-mediated B cell triggering.     

The effect of gamma interferon on IL-1 secretion of in vitro differentiated human macrophages

After being cultured overnight, human monocytes lose their ability to secrete interleukin-1 (IL-1) when stimulated by lipopolysaccharide (LPS). However, when these monocytes were cultured for up to 9 days with various concentrations of interferon-gamma (IFN-gamma), these cells were found to retain their ability to secrete appreciable amounts of IL-1 on LPS stimulation. However, the effect was observed only if the monocytes were exposed to the IFN before LPS stimulation and simultaneous addition of IFN and LPS to macrophages was ineffective. This effect of IFN-gamma was related to the concentration of IFN added to the cultures and was completely neutralized by a monoclonal antibody to IFN-gamma. In addition to inducing IL-1 secretion, IFN-gamma also appeared to increase the overall production of IL-1, since reinduction of IL-1 secretion was not associated with a decrease in intracellular IL-1 content. When these macrophages were initially cultured with IFN-gamma, washed, and further cultured with IFN free medium, these macrophages were found to progressively lose their capacity to secrete IL-1 in response to LPS. Conversely, when monocytes were initially cultured in medium free of IFN, washed, and then further cultured in new medium, but now containing IFN-gamma, these macrophages were found to regain their capacity to secrete IL-1. However, the amount of reinduced IL-1 secretion decreased as the length of the initial culture period without IFN increased, with less than optimal IL-1 secretion occurring if monocytes were allowed to mature for 6 days before IFN-gamma pretreatment. In summary, these studies suggest that IFN-gamma may be important in enhancing IL-1 production and secretion by maturing macrophages and tissue macrophages and consequently may play a role in regulating the accessory cell activity of these cells for a variety of immune responses in vivo.     

Interferon-gamma (IFN-gamma) and prostaglandin E2 (PGE2) regulate differently IL-12 production in human intestinal lamina propria mononuclear cells (LPMC).

IL-12 modulates Th1 immune response during chronic colitis. Mechanisms regulating IL-12 synthesis in human intestine are poorly understood. The aim of this study was to investigate the effect of IFN-gamma and PGE2 on lipopolysaccharide (LPS)-stimulated LPMC IL-12 production. Normal LPMC cultures were run in the presence or absence of IFN-gamma and/or PGE2 before LPS stimulation. To examine the role of endogenous PGE2 on LPS-stimulated IL-12 release, LPMC cultures were added of indomethacin before LPS stimulation. IL-12, IL-10 and IL-8 were measured by ELISA. No IL-12 was detected in either unstimulated or LPS-stimulated LPMC cultures. In contrast, LPMC released IL-8 (650 +/- 125 pg/ml) and IL-10 (75 +/- 25 pg/ml) in response to LPS. Treatment of LPMC with IFN-gamma facilitated LPS-stimulated IL-12, whereas it completely abrogated IL-10 production. IL-12 release by LPMC stimulated with IFN-gamma and LPS was significantly inhibited by exogenous IL-10. The addition of PGE2 to IFN-gamma-treated LPMC cultures inhibited in a dose-dependent manner LPS-induced IL-12 secretion. Furthermore, IL-12 was detectable (85 +/- 25 pg/ml) in the supernatants of LPMC cultures treated with indomethacin and LPS. In contrast to the effect on IL-12, PGE2 significantly augmented LPS-stimulated LPMC IL-10 production. However, the inhibition of IL-12 by PGE2 was only partially reversed by anti-IL-10. In a simplified model of LPS tolerance, we finally showed that monocyte-derived macrophages exhibited reduced IL-12 production after repeat LPS stimulation. In these cell cultures, indomethacin abrogated the induction of LPS desensitization. IFN-gamma and PGE2 modulate differently the LPMC responsiveness to LPS in terms of IL-12 synthesis.     

IL-13抑制人肾小球系膜细胞IL-12的表达

为了探讨白细胞介素 13(IL 13)对体外培养的人肾小球系膜细胞产生白细胞介素 12 (IL 12 )的影响。我们用脂多糖(LPS 10 μg/ml) ,不同浓度的IL 13对系膜细胞培养 ,分别采用ELISA法和半定量RT PCR法检测细胞上清液的IL 12和系膜细胞IL 12p4 0mRNA表达。结果提示 5 %NCSRPMI 16 4 0基础培养条件下的系膜细胞未检测到IL 12蛋白分泌及其mRNA表达。在LPS刺激下系膜细胞的IL 12p4 0mRNA表达加强 ,并分泌出大量的IL 12。IL 13在 1～ 10 0ng/ml浓度范围内对LPS诱导的系膜细胞IL 12分泌及IL 12p4 0mRNA表达的抑制作用呈剂量依赖趋势。本研究认为IL 13可能通过抑制IL 12的产生 ,而调整了体内Th1/Th2细胞因子平衡 ,作为抗炎性细胞因子在肾小球肾炎发病机制中发挥一定作用     

A simple rapid method for detection of IL-2 in a physiological medium

The Con A-activated proliferation of C57BL/6 mice thymus cell suspension is completely blocked by a low concentration of hydrocortisone. This inhibition is reversed by the addition of a 24 h Con A-activated splenic cell supernatant to the thymic cell culture. The restoring activity is completely destroyed by heating. Restoration is not obtained by addition of IL-1-rich supernatant from an LPS-activated peritoneal adherent cell population. The supernatant of a 24 h splenic cell culture activated by Con A in the presence of indomethacin not only restores hydrocortisone-blocked thymocyte reactivity but also enhances thymic cell stimulation. Addition of PGE to the splenic cell culture inhibits the restoring potency of the supernatant. These results are in accord with the proposition that IL-2 is responsible for the restoring phenomenon. These properties have been used to develop a semi-quantitative method for detection of IL-2 in a physiological medium.     

Expression of IL-18 in patients with head and neck squamous cell carcinoma

Interleukin-18 (IL-18), a recently described cytokine secreted mainly by macrophages, stimulates interferon-gamma (IFN-gamma) production by natural killer cells and T cells. The purpose of this study was to determine tissue expression and serum levels of IL-18 in head and neck squamous cell carcinoma (HNSCC) and to evaluate ethanol and endotoxin-driven cytokine secretion. In 24 patients with primary HNSCC and 28 healthy controls, PBMC were isolated and incubated with 50 mM ethanol, LPS (doses 25 ng/ml, 250 ng/ml, 2500 ng/ml) and both agents for 24 h. Levels of IL-18 in serum, and cell supernatants were analysed by capture ELISA, IL-18 tissue level by immunoblotting. Serum levels of IL-8, IL-10 and IL-12, IFN-gamma, and endotoxin plasma levels were also determined. Statistical analysis involved Welch t-test and Page's test for trend. The majority of patients with HNSCC had high concentrations of serum IL-18. The level of IL-18 in the sera of these patients had a mean level of 271.7 pg/ml, while the mean IL-18 serum level in healthy controls was 174,0 pg/ml (p<0.001). Levels of IL-10 and IL-12, IFN-gamma were not increased in patients. Endotoxin was not detectable in either group. LPS stimulated dose-dependently IL-18 secretion from PBMC of patients and controls in vitro (p<0.05). Incubation with ethanol alone did not affect basal IL-18 secretion, but ethanol reduced LPS-stimulated IL-18 secretion compared to LPS stimulation alone. The mRNA expression of IL-18 in unstimulated PBMC and the response of PBMC to ethanol and LPS was similar in patients and controls. Our data on elevated serum levels of IL-18 in the majority of HNSCC cancer patients, irrespective of its biological activity, suggest that serum IL-18 might be a candidate for a new marker for HNSCC. The pathways for IL-18 production and its mechanisms of action in patients with HNSCC remain to be determined. Understanding of the immunological pathways might offer new therapeutic options in head and neck cancer in the future.     

The Role of Thymocytes in Regulating Thymic Epithelial Cell Growth and Function

The basic tenet underlying the present work and supported by recent studies is that there is a dialogue between developing thymocytes and thymic stromal cells. One direction in this dialogue, i. e. thymic stromal cell role in shaping thymocyte maturation, has been extensively studied. The other direction, thymocyte effect on stromal cell development and function, started to emerge only recently on the basis of in vivo observations in SCID and knockout mice. An in vitro approach to the analysis of this interaction may add substantial insight into the process, as demonstrated by the present work. We made use of a culture system of either murine thymic epithelial cells (TEC line) cultured alone or cocultured with thymocytes. Unstimulated thymocytes or their supernatant caused 40–80% inhibition of TEC cell proliferation, as measured by ³H-thymidine incorporation. Cell cycle analysis by flow cytometry indicated that this inhibition can be attributed to reduction in G₂/M phase cell number pari passu with an increase in G_o/G₁ cell number. This inhibitory effect was found to be partially mediated by TGF-β produced by thymocytes. On the other hand, thymocytes augmented IL-6 production by TEC cells in coculture, an effect which could not be reproduced by thymocyte culture supernatant and was not inhibited by thymocyte pretreatment with formaldehyde or emetine. Furthermore, antibodies against thymocyte adhesion molecules (CD2, LFA-1) blocked the thymocyte-induced IL-6 secretion. IL-6 was found to be an autocrine growth factor of TEC in culture, since a combination of anti IL-6 and anti IL-6 receptor antibodies caused 70% inhibition of TEC proliferation and addition of exogenous recombinant IL-6 doubled the rate of proliferation. These results suggest that thymocytes regulate thymic epithelial cell growth by a complex set of inhibitory and enhancing signals mediated through either soluble factors or direct contact. The ultimate effect is dependent on the balance between different signals and may be different in different microenvironmental settings in vivo. In coculture in vitro the dominant effect was growth inhibition of the epithelial cells by thymocytes.     

CD40 ligation-induced cytokine production in human skin explants is partly mediated via IL-1

CD40 ligation by CD40 ligand(+) CD4(+) T cells has been claimed to be involved in inflammatory responses in human skin. However, these data are derived from in vitro cell culture systems and immunohistochemistry, and the mechanisms involved have not been fully elucidated. We previously observed that cells in intact normal human skin secrete high levels of IL-6 and IL-8 upon stimulation with IL-1 beta. In vitro studies have shown that CD40 ligation on human keratinocytes results in the production of IL-6 and IL-8 as well. We used a novel tissue culture system with intact normal human skin, and show that antibody ligation of CD40 results in the induction of several pro- and anti-inflammatory cytokines. IL-6, IL-8, tumor necrosis factor (TNF)-alpha, IL-12 and IL-1 beta were induced upon CD40 ligation and IFN-gamma stimulation, while IL-10 could be induced by CD40 ligation alone and was reduced again by the addition of IFN-gamma. Since CD40 ligation on monocytes and dendritic cells in vitro results in the secretion of IL-1, which is pre-stored in high concentrations in normal human keratinocytes, we subsequently investigated whether CD40 induced IL-6 and IL-8 production in skin is mediated via IL-1. Indeed IL-1 receptor antagonist inhibited the CD40 ligation-induced IL-6 and IL-8 production, while TNF-alpha and IL-10 production were not affected. These data show that CD40 ligation-induced secretion of IL-6 and IL-8, but not TNF-alpha and IL-10, is partially mediated via IL-1 and that IL-1 plays a prominent role in the inflammatory response initiated by CD40 ligation in intact human skin.     

Augmentation of naive,Th1 and Th2 effector CD4 Responses by IL-6, IL-1 and TNF

The role of antigen-presenting cell (APC)-derived cytokines in T cell activation is still controversial. Highly purified CD4 T cell populations of the naive and short-term Th1 and Th2 effector subsets were examined. Stimulation from anti-CD3 in the absence of APC was used to analyze directly T occurring cell-mediated effects, and the requirement for co-signaling was addressed using anti-CD28. Exogenous IL-6, IL-1 and TNF each enhanced proliferation and IL-2 secretion from naive cells, although IL-6 was most active in this regard. Peak responses, however, were obtained with IL-1 or TNF in combination with IL-6 resulting in up to 11-fold increases in IL-2 secretion. Enhanced naive T cell responses were only observed with anti-CD3 and anti-CD28, suggesting that co-signaling through surface-bound receptors was required to initiate IL-2 production. Although the cytokines enhanced naive activation, little effect was seen on differentiation into effector populations. IL-6 alone, or in combination, partially suppressed effectors secreting IFN-γ, but did not promote generation of effectors secreting IL-4. In contrast to reports on cloned cell lines, IL-6, TNF and IL-1 had enhancing activities on all cytokines elicited from already generated Th1 and Th2 effector populations. Again combinations of IL-6, TNF and IL-1 were most effective and generally required CD28 signaling. Induced responses with preexisting effector cells were far less than with naive cells and predominantly directed at augmenting IFN-γ and IL-5 secretion rather than IL-2 and IL-4. These studies show that APC-derived cytokines can promote T cell responses directly but largely after co-stimulation from accessory molecule co-receptors, that the effect is not specific for one T cell subset or cytokine, and that the naive T cell is the main target of action.     

Cytokine regulation of human monocyte interleukin-1 (IL-1) production in vitro. Enhancement of IL-1 production by interferon (IFN) gamma, tumour necrosis factor-alpha, IL-2 and IL-1, and inhibition by IFN-alpha.

IL-1 production (secreted and cell-associated) was measured in monocyte cultures stimulated by a variety of agents in vitro. Monocytes either adherent to conventional plastic culture plates in serum-free conditions, or in suspension in culture medium containing serum were stimulated to produce IL-1 during culture. In non-adherent, serum-free conditions, monocytes produced very low or undetectable amounts of IL-1 during 20 h of culture. Lipopolysaccharide (LPS) induced equivalent amounts of secreted and cell-associated IL-1, although at very low concentrations more cell-associated IL-1 was produced. IL-1 production in response to LPS could be augmented by crude lymphokine, IFN-gamma, or tumour necrosis factor (TNF) alpha. TNF-alpha preferentially augmented the production of cell-associated IL-1 in LPS-stimulated cultures. TNF-alpha induced a significant amount of IL-1 (mainly cell-associated) directly but could also induce IL-1 secretion when combined with IL-2 or IFN-gamma, or when in the presence of serum. IL-2 acted synergistically with low concentrations of IFN-gamma or IL-1 to induce significant levels of IL-1 production. IFN-alpha did not induce any IL-1 production, but was a potent inhibitor of IL-1 production induced by a variety of stimuli. These results suggest that IL-1 production may be enhanced or reduced by different cytokines at concentrations likely to be found in chronic inflammatory lesions.     

The inhibitory effect of quercetin on IL-6 production by LPS-stimulated neutrophils

Quercetin is a herbal flavonoid derived from various foods of plant origin and plays a role in anti-inflammation. Although a number of researches in the field have been done, the mechanism of anti-inflammatory effect of quercetin should be further darified. In the present study, we investigated the effects of quercetin on IL-6 production by LPS-stimulated neutrophils in human. Neutrophils were were pre-treated with quercetin at the final concentrations of ranging from 0-80 ~M for 30 rain, or not treated, and then incubated in the presence or absence of lipopolysaccharide （LPS） at a final concentration of 100 ng/ml for indicated time. The secretion level of IL-6 in the culture supernatants was assayed by ELISA, the intracellular level of IL-6 was detected by flow cytometry and the expression of IL-6 mRNA was analyzed by RT-PCR. The experiment results showed that neutrophils cultured with medium or quercetin alone did not express IL-6, but LPS （100 ng/ml） induced IL-6 expression of neutrophils. However, after pre-treatment of neutrophils with quercetin （40 ~Vl） for 30 rain, the inducible effects of LPS on the increase of IL-6 secretion, intracellular IL-6 level and IL-6 mRNA expression by neutrophils were abrogated. IL-6 is one of the important pro-inflammatory factors, especially in early phage of inflammation. Thus, our data suggested that quercetin might exert its anti-inflammatory effect through negatively modulating pro-inflammatory factors, such as IL-6. The inhibitory effects of quercetin on IL-6 production by neutrophils may provide a theoretical basis on future therapy of inflammation. Cellular ＆ Molecular Immunology. 2005;2（6）：455-460.     

A macrophage-derived factor induced by alpha 1-acid glycoprotein that inhibits IL-1 comitogenic activity

After exposure to a concanavalin A (Con A)-unreactive variant of alpha 1-acid glycoprotein (AGP), macrophages released an inhibitor of interleukin-1 (IL-1) proliferative activity in the thymocyte comitogenic assay. This effect was observed with AGP concentrations above 100 micrograms/ml in the macrophage supernatant and would appear to be mediated by the macrophages, since native AGP had no activity on thymocyte proliferation. Preliminary physicochemical characterization showed that the factor was partially resistant to heating, undialyzable, and eluted with an apparent molecular mass of 50-100 kDa when subjected to Sephacryl S-200 chromatography. Murine IL-1 and human (h) recombinant (r) IL-1 were affected by this factor to the same extent. IL-1 and IL-2 co-induced thymocyte proliferation, which is mitogen-independent, was also inhibited, whereas hrIL-2 activity was not suppressed when assayed in thymocytes with PHA at a submitogenic concentration or in CTLL cells. The factor did not interfere with TNF alpha or hrIL-6 activity when tested against their specific cell line. These data indicate that the inhibitor may act specifically against IL-1 activity and further elucidate the possible role of AGP in the modulation of IL-1 activity via the secretion of an inhibitor.     

LPS的直接诱导对肺微血管内皮细胞IL-8的表达及对PMN趋化作用影响的研究

目的探讨LPS的直接诱导作用对肺微血管内皮细胞(PMVEC)IL -8表达的影响及诱导发生的PMVEC对多形核中性粒细胞 (PMN)趋化作用的影响。方法100ng/mlLPS刺激PMVEC0、1、2、4、6、8h或1、10、100ng/mlLPS刺激6h,ELISA和原位杂交试验分别检测培养液上清中分泌的IL -8及PMVEC内IL-8mRNA的表达 ,同时琼脂糖平板法检测对PMN的趋化作用 ,并通过抗IL -8的抗体抑制试验观察对趋化作用的影响。结果LPS能显著促进PMVEC表达IL -8 ,包括促进IL-8mRNA的表达及IL -8的分泌。在时间上mRNA的表达先于IL -8分泌。LPS能促进PMVEC对PMN的趋化 ,随刺激作用的持续 ,诱导的PMVEC对PMN的趋化作用加强。抗IL -8抗体能显著抑制对PMN的趋化作用(P<0.01)。结论表明细菌致病因子LPS的直接诱导确能促进PMVEC高效表达和分泌IL -8 ,从而为PMN的迁移提供必需的物质条件,发挥对PMN的趋化作用而参与导致肺损伤。     

IL-4 enhances IEC-6 intestinal epithelial cell proliferation yet has no effect on IL-6 secretion

Intestinal epithelial cells (IEC) form an important line of defence at the intestinal mucosa by providing a barrier to lumenal contents and also by their ability to secrete various inflammatory cytokines. Recently, several T cell-derived cytokines have been shown to regulate specific IEC functions. In this study, the effect of IL-4 on IEC proliferation and secretion of the inflammatory cytokine IL-6 was investigated using the non-transformed rat IEC-6 intestinal epithelial cell line. Recombinant rat (rr)IL-4 was found to enhance IEC-6 cell proliferation over 4 days of culture, and this enhancement was dose-dependent. Further studies using specific antibodies confirmed that IL-4 induced the effect and that the effect was not mediated by autocrine-produced transforming growth factor-alpha. However, IL-4 did not induce IL-6 secretion by the IEC-6 cells, nor did it alter IL-1β-induced IL-6 secretion. These results indicate that T cells may be capable of regulating IEC proliferation via the secretion of IL-4 without altering the capacity of the IEC to function in the inflammatory response by secreting IL-6.     

Regulation of C3 and factor H synthesis of human glomerular mesangial cells by IL-1 and interferon-gamma.

Previous reports have shown production of complement components C4, C2 and factor B by renal tissue. We have shown recently that human proximal tubular epithelial cells (PTEC) synthesize C3 in vitro, and that IL-2 enhances this production. In the present study we demonstrate that human mesangial cells (MC) in culture produce factor H and that supernatants of activated peripheral blood mononuclear cells (T cell growth factor (TCGF)) induce C3 production and enhance factor H synthesis in both a time- and dose-dependent manner. To investigate whether certain defined cytokines from TCGF were responsible for the observed effect, we tested various cytokines for their effect on complement production by MC. It is shown that IL-1 induces C3 synthesis whereas factor H production is up-regulated by IFN-gamma, in both a dose- and time-dependent manner. Antibody blocking experiments revealed that C3 synthesis induced by both TCGF and IL-1 could be blocked with antibodies specific for IL-1, and also that TCGF and IFN-gamma enhanced factor H synthesis could both be blocked with antibodies specific for IFN-gamma. Cycloheximide was able to inhibit C3 and factor H production, suggesting de novo synthesis of the proteins. mRNA-polymerase chain reaction (PCR) analysis revealed mRNA encoding for C3 after stimulation with TCGF and IL-1. Factor H genes are constitutively expressed in cultured mesangial cells and its expression is up-regulated by TCGF and IFN-gamma. Northern blot analysis with specific probes for C3 and factor H revealed bands which support the results obtained by PCR analysis.     

Signal delivery by physical interaction and soluble factors from accessory cells in the induction of receptor-mediated T-cell proliferation. Synergistic effect of BSF-2/IL-6 and IL-1.

Our recent study revealed that soluble factors derived from accessory cells (AC; monocytes) and physical interaction with T cells of the accessory cells are both required for the induction of the proliferation of human peripheral blood T cells by anti-CD3 antibody coupled on latex beads. The accessory cell-derived soluble factor could be replaced by IL-1 and IL-6, and the role of live macrophages for physical interaction with T cells was found to be replaceable with paraformaldehyde(PFA)-fixed macrophages, provided the macrophages were pretreated with interferon-gamma (IFN-gamma) before fixation. Quantitative analysis in the present study revealed that IL-1 and IL-6 act synergistically to induce T-cell proliferation in the above system but either one of the factors alone reveals only a marginal or weak activity. Furthermore, it was shown that the potentiating activity of the culture supernatants of monocytes was substantially inhibited by anti-IL-6 antibody. Taken together with our previous results that anti-IL-1 serum strongly inhibited the potentiating activity of the culture supernatant, these results indicate that the main responsible molecules in the culture supernatant are IL-1 and IL-6, although a presence of other effective factors is not excluded. The anti-CD3-induced thymidine uptake by T cells in the presence of IL-1 and IL-6 was significantly inhibited by anti-Tac antibody, suggesting that the proliferation of T cells in this system is mostly mediated by a IL-2-dependent pathway. Our study further showed that accessory cells seem to acquire cell surface properties necessary for the effective interaction with T cells during 6-24 hr of culture with IFN-gamma. Presumably, a certain molecule(s) required for the interaction is induced on the cell surface of the AC by IFN-gamma.     

衰变加速因子在Jurkat细胞增殖及分泌IL—2中的作用

目的 研究衰变加速因子对CD3阳性与阴性Jurkat细胞的增殖效应及对IL－2分泌的影响。方法 应用MTT比色实验观察交联DAF单抗DG3与固相化抗CD3联合作用对CD3阳性与CD3阴性Jurkat细胞增殖效应;IL－2依赖CTLL^3H-TdR掺入实验检测CD3阳性与CD3阴性Jurkat细胞IL－2的分泌;细胞ELISA检测CD3阳性与CD3阴性Jurkar细胞IL－2R的表达。结果 交联DG3可协助促进固相化抗CD3对CD3阳性Jurkat细胞的增殖效应和IL－2分泌,并可引起IL－2Rα链表达增加,此作用可被Src家族酪酸激酶抑制剂PP2所抑制,而对CD3阴性Jurkat细胞无此作用。结论 衰变加速因子可协同促进固相化抗CD3对CD3阳性Jurkat细胞的刺激增殖效应、IL－2分泌及IL－2R表达增加。     

Interplay between IL-2 and IL-4 in human thymocyte differentiation: antagonism or agonism

The effect of recombinant interleukin 2 (IL-2) and IL-4, as well as a combination of both lymphokines on human post-natal thymocytes at different maturation stages, was analyzed by culturing highly purified pro-T cells, pre-T cells, double-negative and double-positive thymocyte subsets in the presence of IL-2 and/or IL-4. Both IL-2 and IL-4 responsiveness are developmentally regulated in human thymocytes, since IL-2 and IL-4 responses decline with increasing thymocyte differentiation, double-positive T cells displaying far less proliferation than immature thymocytes. IL-2 and IL-4 may influence pro-T cell growth in both an antagonistic and additive fashion. At low doses, IL-4 inhibits IL-2-supported growth of pro-T cells, whereas, at higher concentrations, this inhibitory effect is masked by the ability of IL-4 to stimulate pro-T cell proliferation. In contrast to peripheral lymphocytes, IL-4 does not down-regulate the expression of the IL-2 receptor light chain on thymocytes. In pro-T cell cultures, IL-2 and IL-4 favour the differentiation of distinct cell populations, namely lymphocytes displaying preferentially a TCR alpha/beta+ and CD4+CD8- phenotype versus predominantly TCR gamma/delta+ and CD4-CD8+ cells, respectively. The effect of IL-2 dominates over that of IL-4, since the composition of cultures set up in the presence of IL-2 plus IL-4 resembles that of cells cultured with IL-2 alone. In synthesis, IL-2 and IL-4 exhibit reciprocal inter-relations in human thymocyte cultures, thus supporting the notion that these lymphokines are implicated in the complex regulation of a local cytokine network.