白细胞介素-5增强嗜酸性粒细胞呈递抗原的能力

我们以前曾证实嗜酸性粒细胞 (ＥＯＳ)经粒细胞 巨噬细胞集落刺激因子 (ＧＭ ＣＳＦ)刺激后可以表达Ⅱ类主要组织相容性复合体基因所编码的蛋白分子(如人ＥＯＳ的ＨＬＡ ＤＲ) 〔1〕 以及协同刺激分子如Ｂ7 1(ＣＤ80 )和Ｂ7 2 (ＣＤ86 )等〔2〕,并因此成为抗原呈递细胞 ,能够将抗原呈递给Ｔ细胞从而促使后者进行增殖。本研究的目的是探讨ＴＨ2淋巴细胞产生的白细胞介素 5 (ＩＬ 5 )能否增强ＥＯＳ将抗原呈递给自体Ｔ淋巴细胞的能力。材料和方法人ＥＯＳ和自体Ｔ细胞的分离和纯化的方法详见文献〔1〕。 6名健康志愿者的血浆作为本研究的基本…     

嗜酸性粒细胞可作为抗原呈递细胞

目的探讨ＨＬＡ－ＤＲ＋嗜酸性粒细胞（ＥＯＳ）在体外培养条件下作为抗原呈递细胞（ＡＰＣ）将破伤风类毒素抗原（ＴＴ）呈递给Ｔ淋巴细胞的能力。方法新分离的ＥＯＳ经人重组粒细胞－巨噬细胞集落刺激因子刺激２４小时,以诱导ＨＬＡ－ＤＲ的表达,然后将其暴露于不同浓度的ＴＴ,检测ＨＬＡ－ＤＲ＋ＥＯＳ对自身Ｔ细胞增殖反应的影响,以评价ＥＯＳ呈递抗原的能力。结果ＨＬＡ－ＤＲ＋ＥＯＳ于ＴＴ存在时可以明显促进Ｔ细胞的增殖反应,并与ＴＴ的浓度呈剂量相关性。而抗ＨＬＡ－ＤＲ单克隆抗体则可以明显地抑制ＥＯＳ的抗原呈递过程。结论人ＥＯＳ可以摄入和处理抗原并能将其传递给自身Ｔ细胞,而ＥＯＳ呈递抗原的过程具有明显的ＨＬＡ－ＤＲ依赖性。     

060 CD28增强免疫新分子ICOS的表达及其时CD4+T细胞分化的调节作用

可诱导刺激分子 (ＩＣＯＳ)为新近发现的ＣＤ2 8/ＣＤ1 52受体家族的新成员 ,为表达于Ｔ细胞表面的与Ｔ细胞活化有关的分子 ,其配体分子为Ｂ7ＲＰ 1。小鼠的ＩＣＯＳ与ＣＤ2 8、ＣＴＬＡ4的氨基酸序列分别有 38%和 31 %的同源性。与ＣＤ2 8不同的是ＩＣＯＳ表达于活化的Ｔ细胞 ,发挥协同刺激通路的作用 ,而ＣＤ2 8对于处于免疫应答早期的Ｔ细胞的活化有重要作用。为了研究免疫新分子ＩＣＯＳ在ＣＤ4 +Ｔ细胞活化中的调节作用以及与ＣＤ2 8的关系 ,该文采用抗小鼠ＩＣＯＳ特异性单抗来检测小鼠的ＩＣＯＳ表达并以ＩＣＯＳ Ｉｇ阻断ＩＣＯＳ与…     

胸腺基质细胞的抗原提呈作用

目的 研究胸腺基质细胞的抗原提呈能力。方法 应用ＯＶＡ－特异的、受Ｉ－Ａ＾ｄ分子识别限制的辅助Ｔ细胞杂交瘤（３ＤＯ．１８．３）识别提呈的ＯＶＡ的ＣＮＢｒ水解片段而被活化后产生ＩＬ－２,测定ＩＬ－２活性来分析胸腺基质细胞的抗原提呈作用。结果ＩＦＮ－γ能促进ＭＴＥＣＩ和ＭＴＳＣ４表达Ｉ－Ａ＾ｄ分子,并促进ＭＴＳＣ４表达Ｂ７－１分子。经ＩＦＮ－γ作用后,ＭＴＥＣ１和ＭＴＳＣ４均有抗原提呈能力,ＭＴＳＣ     

7株小鼠胸腺基质细胞系诱导裸鼠骨髓干细胞表达CD4及CD8分子

为研究胸腺微环境在Ｔ细胞发育中的作用，我室在体外建立了７株小鼠胸腺基质细胞系，命名为ＭＴＥＣＩ～ＭＴＥＣ７。通过初步分离得到裸鼠骨髓富含干细胞的细胞群，表面ＣＤ４及ＣＤ８分子均为阴性。将分离的骨髓干细胞与胸腺基质细胞共育３天后，经双色荧光抗体染色，ＦＡＣＳ分析发现胸腺基质细胞可诱导裸鼠骨髓干细胞表达ＣＤ４ＣＤ８分子。ＭＴＳＣ－ＳＮ及ＭＴＳＣ主要诱导的是ＣＤ４＋ＣＤ８－细胞，部分ＣＤ４＋ＣＤ８＋细胞，而ＣＤ４－ＣＤ８＋细胞极少，这种诱导特点可能和基质细胞系的类型有关。     

7株小鼠胸腺基质细胞系诱导裸鼠骨髓干细胞表达CD4…

为研究胸腺微环境在Ｔ细胞发育中的作用，我室在体外建立了７株小鼠胸腺基质细胞系，命名为ＭＴＥＣ１－ＭＴＥＣ７。通过初步分离得到裸鼠骨髓富含干细胞的细胞群，表面ＣＤ４及ＣＤ８分子均为阴性，将分离的骨髓干细胞为胸腺基质细胞共育３天后，经双色荧光抗体染色，ＦＡＣＳ分析发现胸腺基质细胞可诱导裸鼠骨髓干细胞表达ＣＤ４ＣＤ８分子。ＭＴＳＣ－ＳＮ及ＭＴＳＣ主要诱导的是ＣＤ４＾＋ＣＤ８＾－细胞，部分ＣＤ４＾＋ＣＤ８     

小鼠胸腺基质细胞系（MTEC1）对裸鼠骨髓细胞的诱…

在体外建立的小鼠胸腺基质细胞系（ＭＴＥＣ１）及其培养上清（ＭＴＥＣ１－ＳＮ）与裸鼠骨髓（ＢＭ）细胞共同培养，通过直接荧光素标记抗体，ＦＡＣＳ分析其细胞表面标志表明，ＭＴＥＣ１及ＭＴＥＣ１－ＳＮ均有诱导促进Ｔｈｙ·１＾－ＣＤ＾－４ＣＤ＾－８的ＢＭ细胞表达Ｔｈｙ·１，ＣＤ４及ＣＤ８分子的作用。在培养或共育三天时，ＭＴＥＣ１－ＳＮ可促进ＢＭ细胞分化形成ＣＤ＾＋４Ｔｈｙ·１＾－，ＣＤ＾－４Ｔｈｙ·１＾＋细     

CD80和CD86研究进展

ＣＤ８０，ＣＤ８６是近年来发现的两个参与Ｔ细胞活化的协同刺激分子。本文综述了其基因结构、分析及表达、免疫学功能及其受体系统，特别提出了ＣＤ８０，ＣＤ８６在肿瘤转基因治疗中的作用。     

CD80和CD86研究进展

ＣＤ８０，ＣＤ８６是近年来发现的两个参与Ｔ细胞活化的协同刺激分子。本文综述了其基因结构、分析及表达、免疫学功能及其受体系统，特别提出了ＣＤ８０，ＣＤ８６在肿瘤转基因治疗中的作用。     

系统性红斑狼疮患者CD28表达及其意义

ＣＤ２８是Ｔ细胞激活中重要的共刺激分子。为了解Ｂ７－Ｃ礤刺激途径在系统性红斑狼疮（ＳＬＥ）中的作用，我们对３０例期ＳＬＥ２外周血Ｔ细胞ＣＤ２８的表达进行了检测，并分析了其激活后凋亡情况。结果表明，ＳＬＥ组的ＣＤ２８Ｔ细胞低于正常对照组，在抗ＣＤ３单抗刺激后ＣＤ２８细胞凋亡率增加。这提示ＳＬＥ中Ｂ７－ＣＤ２８共刺激途径介导的ＡＩＣＤ可能导致ＳＬＥ中的Ｔ细胞淋巴细胞贫血症。     

Priming to Mycobacterial Antigen In Vivo Using Antigen-Pulsed Antigen Presenting Cells Generated In Vitro is Influenced by the Dose and Presence of IL-4 in APC Cultures

Antigen presenting cells (APC) similar to immature dendritic cells can be generated in vitro from bone marrow precursors. The authors have compared the yield, the phenotype and the function of murine bone marrow cells cultured for 7 or 11 days in either granulocyte macrophage colony stimulating factor alone (GM BMAPC) or in combination with interleukin-4 (GM/IL-4 BMAPC). The results showed that GM/IL-4 BMAPC expressed the highest levels of MHC Class 2 molecules, CD86 /B7-2 and CD80/B7-1 co-stimulatory molecules and the lowest levels of F4/80 macrophage marker. However, when these APC were pulsed with BCG culture filtrate antigen or PPD they were not correspondingly more effective at stimulating activated T lymphocytes in vitro or priming naive T lymphocytes in vivo . Also, in contrast to GM BMAPC, high backgrounds recorded following injections of GM/IL-4 BMAPC without antigen were not consistently reduced by lowering the dose and irradiating the cells prior to administration. The authors conclude that the degree of maturity of BMAPC varies with culture conditions and that this may be an important consideration where BMAPC are to be used in vivo in immunotherapeutic regimens.     

CD28 interactions with either CD80 or CD86 are sufficient to induce allergic airway inflammation in mice.

Previous studies have shown that the pan CD28/cytotoxic T lymphocyte antigen (CTL)A-4 antagonist CTLA4 immunoglobulin (Ig) inhibits eosinophilic airway inflammation in Schistosoma mansoni-sensitized and airway-challenged mice. In the present study, the importance of CD28 as well as the individual roles of CD80 and CD86 were examined in this system using wild-type and CD28 knockout (KO) mice. Unlike wild-type controls, CD28KO mice did not produce systemic IgE or eosinophilic airway inflammation after antigen challenge. However, a lymphocytic infiltrate and continued production of interferon-gamma was observed in these animals. Thus, CD28 is not essential for the initial recruitment of lymphocytes into antigen-challenged airways but critically regulates the allergic T-helper 2 phenotype. We next determined by polymerase chain reaction and flow cytometry that CD80 and CD86 molecules are constitutively expressed in the naive murine lung and on eosinophils in the allergic lung, suggesting a potential important role for both ligands in the development of asthma. Combined anti-CD80/anti-CD86 treatment throughout the antigen challenge period fully blocked the development of allergic airways, whereas a partial reduction was observed in mice treated with either anti-CD80 or anti-CD86 antibody alone. However, only anti-CD86 blocked systemic IgE production. Therefore, signaling through either CD80 or CD86 is sufficient to generate a partial local allergic response, whereas CD86 costimulation is essential to induce systemic allergic (IgE) reactions. Finally, combined anti-B7 monoclonal antibody treatment after sensitization reduced airway eosinophilia and interleukin (IL)-4/IL-5 cytokine secretion consistent with an ongoing role for CD28/B7 interactions in the effector phase of the disease. These results emphasize the importance of differential B7 expression on different cells and in different organs on subsequent CD28/B7-mediated immune events, including the potential for CD28/B7 blockade in the treatment of atopic airway disease in people.     

Co-stimulation of murine CD4 T cell growth: cooperation between B7 and heat-stable antigen.

The B cell activation antigen B7/BB1 has been shown to co-stimulate growth of human T cells by binding the T cell molecule CD28. In mice, the heat-stable antigen (HSA) has also been shown to act as a co-stimulator for T cell growth. In this study, we have evaluated the contributions of B7 and HSA to the co-stimulatory activity of antigen-presenting cells (APC). Mouse B7 provides co-stimulatory activity for murine CD4 T cells in anti-CD3-induced proliferation. Human CTLA4Ig, a chimeric molecule comprising the extracellular region of CTLA-4 fused to an immunoglobulin C gamma fragment, binds to murine B7. We, therefore, use human CTLA4Ig and the hamster anti-HSA monoclonal antibody 20C9 to analyze the relative contributions of B7 and HSA to the co-stimulatory activity of murine spleen APC. Our data reveal that both murine B7 and HSA are expressed by dendritic cells and by low-density spleen B cells. Either CTLA4Ig alone or anti-HSA alone inhibited CD4 T cell proliferation to anti-CD3 by > 90%, while CTLA4Ig and anti-HSA together were far more efficient in inhibiting clonal expansion of CD4 T cells. These results demonstrate that functionally defined co-stimulation involves at least B7 and HSA and suggest that signals delivered by B7 and HSA synergize in promoting T cell growth.     

CD28-B7-mediated T cell costimulation in chronic cardiac allograft rejection: differential role of B7-1 in initiation versus progression of graft arteriosclerosis

Provision of adequate T cell costimulation is critical for the development of acute and chronic allograft rejection. We have previously reported that early blockade of CD28-B7 T cell costimulation prevents the development of graft arteriosclerosis, in the LEW into F344 rat cardiac transplant model. In this study, we used the same model to examine the requirement for CD28-B7-mediated T cell costimulation in the progression of established chronic rejection and examined the individual roles of B7-1 (CD80) and B7-2 (CD86) costimulatory molecules. Late blockade of CD28-B7 T cell costimulation by the fusion protein CTLA4Ig, which binds both CD80 and CD86, attenuated the development of transplant arteriosclerosis, mononuclear cell infiltration, and parenchymal fibrosis in this model. Selective blockade of CD80 using the mutant fusion protein Y100F was as effective as CTLA4Ig in this regard. In contrast to CTLA4Ig, blockade of CD80 alone by Y100F was ineffective at preventing early graft loss and prolonging graft survival when given early after transplantation. This study is the first to demonstrate that late blockade of CD28-B7 T cell costimulation interrupts chronic cardiac allograft rejection, and it indicates the importance of continued T cell activation in this process. This study further defines functional differences between CD80 and CD86 costimulatory molecules in vivo.     

Up-regulation of the dendritic cell marker CD83 on polymorphonuclear neutrophils (PMN): divergent expression in acute bacterial infections and chronic inflammatory disease

Upon cultivation with interferon-gamma (IFN-gamma ) and granulocyte/macrophage-colony stimulating factor (GM-CSF) polymorphonuclear neutrophils (PMN) acquire characteristics of dendritic cells, including expression of major histocompatibility complex (MHC) class II antigens, of the co-stimulatory antigens CD80, CD86 and of CD83, the latter considered to be specific for dendritic cells. Dendritic-like PMN were also able to present to T cells antigens in a MHC class II-restricted manner. To assess whether dendritic-like PMN are also generated in vivo, cells of patients with acute bacterial infections and of patients with chronic inflammatory diseases (primary vasculitis) were tested. During acute infection up to 80% of PMN acquired CD83, but remained negative for MHC class II, CD80 or CD86. PMN of patients with primary vasculitis expressed MHC class II antigens, CD80 and CD86, but not CD83, indicating that up-regulation of MHC class II and of CD83 are not necessarily linked to each other. Indeed, parallel studies with PMN of healthy donors showed that while IFN-gamma and granulocyte/macrophage colony stimulating factor (GM-CSF) induced both, MHC class II and CD83, tumour necrosis factor (TNF)-alpha selectively induced de novo synthesis of CD83. The function of CD83 on PMN is still elusive. A participation in the MHC class II-restricted antigen presentation could be ruled out, consistent with the segregation of MHC class II and CD83 expression. Regardless, however, of its function, CD83 expression could serve as a marker to differentiate between acute and chronic inflammation.     

Local gene therapy with CTLA4-immunoglobulin fusion protein in experimental allergic encephalomyelitis

It has been reported previously that the induction phase of experimental allergic encephalomyelitis (EAE) is highly sensitive to systemic blockade of stimulation via MHC class II molecules and co-stimulation via the CD28 : CD80/CD86 pathways. In contrast, the effector phases of EAE were relatively unaffected by similar treatments using MHC class II antigen (Ag)-specific mAb and cytotoxic T lymphocyte antigen (CTLA)4-Ig fusion proteins in some studies. This has been attributed to different sensitivities of effector cell function or the poor penetrance of inhibitory proteins into the central nervous system (CNS). To examine this question further, MHC class II Ag-specific mAb and CTLA4-Ig were delivered directly into the CNS following EAE induction, and both were found to inhibit disease. While it was found that systemic administration of mouse CTLA4-Ig could also inhibit the progression of effector immune responses when administered shortly before or during clinical disease, these were significantly more active when delivered directly into the CNS, which probably involved an action on both CD28 ligands, CD80 and CD86. Although mouse CTLA4-human Ig was therapeutically less efficient than mouse CTLA4-mouse Ig protein, probably due to the enhanced immunogenicity and lower functional activity, gene delivery of CTLA4-human Ig into the CNS using a non-replicating adenoviral vector was more effective than a single injection of CTLA4-human Ig protein. Gene delivery significantly ameliorated the development of EAE, without necessarily inhibiting unrelated peripheral immune responsiveness. Local gene delivery of CTLA4-Ig may thus be an important target for immunotherapy of human autoimmune conditions such as multiple sclerosis.     

Effect of CTLA-4 chimeric protein on rat autoimmune anti-glomerular basement membrane glomerulonephritis

The interaction of the T cell receptor with the antigen/major histocompatibility class II complex is insufficient to induce optimal T cell activation. Co-stimulatory signals, including those provided by CD28/CTLA-4 on T cells and B7 molecules (B7-1, ?2 and ?3) on antigen-presenting cells, are also required. CD28-B7 interactions can be blocked by a soluble human CTLA-4 chimeric protein (CTLA4Ig). We tested the effect of administration of CTLA4Ig on experimental anti-glomerular basement membrane (GBM) autoimmune glomerulonephritis in Wistar-Kyoto rats induced by immunization with bovine GBM. The disease is characterized by development of antibody to the α3 chain of type IV collagen (Goodpasture's antigen), deposition of rat IgG in GBM, infiltration of the kidney by T cells and macrophages, severe crescent formation and renal failure leading to death in 5–6 weeks. Animals injected with human CTLA4Ig from day 0 to day 14 or to day 35 had reduced disease severity. Beneficial effects were observed even when injections were begun after the onset of glomerulonephritis on day 14. However, the rats developed antibody to the human CTLA4Ig, associated with reduction in levels of circulating CTLA4Ig. The results provide evidence for CD28/CTLA-4 signaling in rat autoimmune glomerulonephritis, and suggest that more effective inhibition of B7-dependent T cell activation, such as might be achieved with homologous CTLA4Ig, could be useful in the treatment of autoimmune diseases.     

Immunological potential of cytotoxic T lymphocyte antigen 4 immunoglobulin in murine autoimmune cholangitis

Cytotoxic T lymphocyte antigen 4 (CTLA‐4) immunoglobulin (Ig) is an important regulator of T cell activation and a fusion protein directed at CD80 and CD86; it blocks co‐stimulatory signalling and T cell activation. We have taken advantage of a murine model of human primary biliary cirrhosis (PBC), mice expressing a transforming growth factor (TGF)‐β receptor II dominant negative (dnTGF‐βRII) transgene to address the potential therapeutic efficacy of CTLA‐4 Ig. To mimic patients with PBC at different stages or duration of disease, we treated mice with either CTLA‐4 Ig or control IgG three times weekly from 3 to 12 or 24 weeks of age, or from 12 to 24 weeks of age. CTLA‐4 Ig treatment from 3 weeks of age significantly reduced liver inflammation to 12 weeks of age. Treatment initiated at 12 weeks of age also ameliorated the autoimmune cholangitis at 24 weeks of age. However, in mice treated at 3 weeks of age, suppression of liver inflammation was not sustained and colitis was aggravated when treatment was extended to 24 weeks of age. Our data indicate that, in dnTGF‐βRII mice, CTLA‐4 Ig treatment has short‐term beneficial effects on autoimmune cholangitis, but the effect varies according to duration of treatment and the time in which therapy was initiated. Further dissection of the events that lead to the reduction in therapeutic effectiveness of CTLA‐4 Ig will be critical to determining whether such efforts can be applied to human PBC.     

Quantitative analysis predicts the relative therapeutic efficacy of different forms of CTLA4Ig

Modulating the activities of costimulatory molecules controlling immune responses holds considerable promise for immunotherapy. CTLA4Ig (abatacept), a soluble version of the T cell-expressed membrane receptor CTLA-4, is approved for the treatment of rheumatoid arthritis. Like natural CTLA-4 molecules, CTLA4Ig ligates B7-1 and B7-2 on antigen presenting cells, preventing CD28-mediated costimulation of T cells. However, CTLA4Ig can also prevent ligation of CTLA-4, potentially blocking vital inhibitory signals, thereby augmenting immunity. There have been no quantitative analyses of the likely effects of CTLA4Ig on costimulatory interactions at the immunological synapse. We present a mathematical model, based on rigorous biophysical and expression data, for simulating the effects of abatacept and a mutated derivative, LEA29Y, on the synaptic interactions of CD28 and CTLA-4. The simulations reveal an unexpectedly large window within which CD28, but not CTLA-4, ligation is blocked by CTLA4Ig, perhaps explaining the efficacy of abatacept at the recommended therapeutic dose (10 mg/kg) and its relative safety. However, the simulations suggest that the present dosing regimen is close to the maximum theoretically safe dose. The simulations also show that, within the therapeutic window, LEA29Y enhances the interaction of CTLA-4 with the more potent of its two native ligands, B7-1. They also suggest that CTLA-4 ligation by B7-1 could, in principle, be enhanced by further decreasing the off-rate of CTLA4Ig for binding to B7-2. Our findings therefore offer molecular explanations for why LEA29Y might prove to be more effective than abatacept in a clinical setting, and suggest ways in which its therapeutic efficacy could be further optimised.