CD100 is a leukocyte semaphorin

CD100 was originally described as an activation molecule on the surface of human T lymphocytes. Its triggering through distinct epitopes leads to different signals of costimulation with phorbol myristate acetate (PMA) or with CD3 and CD2. Interestingly, CD100 was shown to associate with different partner molecules in T cells. First, CD100 can associate with CD45, a key molecule with protein tyrosine phosphatase activity involved in T-cell transduction this association is physical and has functional consequences for both partners. Second, CD100 interacts in its cytoplasmic domain with a Ser/Thr kinase for which it represents a preferential substrate. Recently, CD100 was identified as a member of the semaphorin gene family. This family comprises approximately 20 structurally related proteins. The first semaphorins were identified in the developing nervous system. Function has been shown for only some of them and involves repulsion during growth cone guidance. Since CD100 was the first semaphorin identified in the immune system, this raises the possibility of the involvement of members of the semaphorin family in other physiological phenomena outside the nervous system. Received 1 March 1998; received after revision 8 June 1998; accepted 8 June 1998     

Augmentation of natural antiganglioside IgM antibodies in lower motor neuron disease (LMND) and role of CD5+ B cells

IgM antibodies directed against neuronal gangliosides GM₁ , GM₂ , GD_1a , GD_1b and GT_1b occur in normal individuals and their level significantly decreases with age. Patients with lower motor neuron disease (LMND) produce high levels of these autoantibodies. AntiGM₁ IgM is selectively augmented. In these patients, the CD5+ (B1) and CD5− (B2) subsets of B cells are not distinct entities but range from those without detectable CD5 marker to those with high CD5+ expression. B1 B cells were sorted to homogeneity, but B2 B cell cannot be isolated to homogeneity because of the presence of B1 cells with low CD5 expression. In short term cultures both the subsets produced IgM antibodies, but the antibodies reacted better with desialylated GM₁ than with GM₁ . Cycloheximide (Cx) (0.35 mM) largely blocked IgM synthesis of the B1 B cells but inhibition of the B2 B cells was incomplete, possibly due to shedding of cytophilic antibodies as well as to the presence of B1 phenotype with loss of CD5 expression. CD5+ B cells may be involved in the production of antiglycolipid IgM. Received 9 June 1997; received after revision 21 July 1997; accepted 28 July 1997     

Dexamethasone enhances CTLA-4 expression during T cell activation

T cell activation is enhanced by the costimulatory interaction of B7 on antigen-presenting cells and CD28 on T cells, resulting in long-term T cell proliferation, differentiation and production of large amounts of cytokines, such as interleukin (IL)-2. CTLA-4 is a co-stimulation receptor that shares 31% homology with CD28 and binds B7 family members with higher affinity. CTLA-4 is transiently expressed intracellularly and on the cell surface following activation of T cells. We have studied the kinetics of CTLA-4 expression and the effects of dexamethasone on CTLA-4 expression during T cell activation in cultures of mouse spleen cells stimulated by a mixture of immobilized anti-CD3 and anti-CD28 monoclonal antibodies (anti-CD3/CD28 mAb) or concanavalin A (ConA). CTLA-4 expression peaked on day 2 and returned to background levels after 7 days. Dexamethasone was found to potentiate CTLA-4 expression in a dose-dependent manner with an EC₅₀ effective concentration 50%) of about 10⁻⁸ M. In contrast, other immunosuppressive agents, such as rapamycin or cyclosporin A had no or an inhibitory effect on CTLA-4 expression, respectively. Dexamethasone also stimulated CD28 expression, but inhibited IL-2R expression during anti-CD3/CD28 mAb-induced mouse splenic T cell activation. Western blot analyses of lysates of activated mouse T cells showed that dexamethasone increased CTLA-4 protein levels twofold during anti-CD3/CD28 mAb-induced activation. Dexamethasone also enhanced CTLA-4 messenger RNA twofold as quantified by ribonuclease protection assay. The effects of dexamethasone on CTLA-4 expression were glucocorticoid-specific and completely inhibited by the glucocorticoid receptor antagonist mifepristone (RU486), indicating that the effect of dexamethasone on CTLA-4 expression is mediated through the glucocorticoid receptor. In conclusion, the immunosuppressive agent dexamethasone actually stimulates CTLA-4 expression, which is involved in downregulation of T cell activation. Received 19 May 1999; received after revision 13 July 1999; accepted 13 July 1999     

The CD40/CD154 receptor/ligand dyadRID="†"ID="†" Review

Until recently, the expression and primary function of the cell surface receptor CD40 and its ligand CD154 were considered restricted to B and T lymphocytes, and their interactions required for the thymus-dependent humoral response. However, current work from several groups challenges this view of the CD40/CD154 dyad as a mere mediator of lymphocyte communication. A variety of non-lymphocytic cell types express both receptor and ligand, including hematopoetic and non-hematopoetic cells, such as monocytes, basophils, eosinophils, dendritic cells, fibroblasts, smooth muscle, and endothelial cells. Accordingly, ligation of CD40 mediates a broad variety of immune and inflammatory responses, such as the expression of adhesion molecules, cytokines, matrix-degrading enzymes, prothrombotic activities, and apoptotic mediators. Consequently, CD40 signaling has been associated with pathogenic processes of chronic inflammatory diseases, such as autoimmune diseases, neurodegenerative disorders, graft-versus-host disease, cancer, and atherosclerosis. This review focuses on the synthesis and structure of CD40 and outlines CD154/CD40 signaling pathways, and emphasizes the previously unexpected importance of the CD40/CD154 receptor/ligand dyad in a spectrum of immunoregulatory processes and prevalent human diseases. Received 10 January 2000; revised 16 June 2000; accepted 5 July 2000 RID="†" ID="†" Review RID="*" ID="*" Corresponding author.     

Overexpression of HAb18G/CD147 promotes invasion and metastasis via α3β1 integrin mediated FAK-paxillin and FAK-PI3K-Ca2+ pathways

Mechanism of HAb18G/CD147 underlying the metastasis process of human hepatoma cells has not been determined. In the present study, we found that integrin α3β1 colocalizes with HAb18G/CD147 in human 7721 hepatoma cells. The enhancing effect of HAb18G/CD147 on adhesion, invasion capacities and matrix metalloproteinases (MMPs) secretion was decreased by integrin α3β1 antibodies (p<0.01). The expressions of integrin downstream molecules including focal adhesion kinase (FAK), phospho-FAK (p-FAK), paxillin, and phospho-paxillin (p-paxillin) were increased in human hepatoma cells overexpressing HAb18G/CD147. Deletion of HAb18G/CD147 reduces the quantity of focal adhesions and rearranges cytoskeleton. Wortmannin and LY294002, specific phosphatidylinositol kinase (PI3K) inhibitors, reversed the effect of HAb18G/CD147 on the regulation of intracellular Ca²⁺ mobilization, significantly reducing cell adhesion, invasion and MMPs secretion potential (p<0.01). Together, these results suggest that HAb18G/CD147 enhances the invasion and metastatic potentials of human hepatoma cells via integrin α3β1-mediated FAK-paxillin and FAKPI3K-Ca²⁺ signal pathways. Received 5 June 2008; received after revision 16 July 2008; accepted 23 July 2008     

胃癌侧群细胞耐药性研究及干细胞相关基因检测

目的研究胃癌侧群（Side Population,sP）细胞对化疗药物5-Fu（氟尿嘧啶）的耐药性及可能机制,并检测干细胞相关基因Nanog、Musashi-1及cD44的表达情况。方法选择人胃癌细胞株sGc-7901,以荧光染料H0echst 33342染色,维拉帕米桔抗对照,应用流式细胞仪分选sP细胞和nonsP细胞。细胞耐药实验比较sP细胞与nonsP细胞对化疗药物5．Fu的耐药性差异;westem_h10t检测ABcG2和bcl-2蛋白表达情况;流式细胞仪分析细胞周期;荧光定量PcR检测两组细胞中干细胞相关基因Nanog、Musashi-1及cD44mRNA的表达差异。结果胃癌细胞株sGc．790l中sP细胞的比例为2．8％,sP细胞对5-Fu的耐药存活率明显高于non-sP细胞（P〈0．05）,与nonsP细胞相比,sP细胞高表达耐药蛋白ABcG2和抗凋亡蛋白bcl-2,有更多的细胞处于c0／G1期（P〈0．05）,并高表达干细胞相关基因Musashi-1和cD44。结论胃癌sGC_7901细胞株中sP细胞对化疗药物5．Fu的耐药性明显高于nonsP细胞,其耐药机制可能与sP细胞高表达耐药蛋白ABcG2和抗凋亡蛋白bcl-2,有更多细胞处于G0／Gl期有关;Musashi-1和cD44可能是相对特异性的胃癌干细胞标志物。     

Self and non-self discrimination is needed for the existence rather than deletion of autoimmunity: the role of regulatory T cells in protective autoimmunity

Autoimmune T cells have been viewed for decades as an outcome of immune system malfunction, and specifically as a failure to distinguish between components of self and non-self. The need for discrimination between self and non-self as a way to avoid autoimmunity has been repeatedly debated over the years. Recent studies suggest that autoimmunity, at least in the nervous system, is the bodys defense mechanism against deviations from the normal. The ability to harness neuroprotective autoimmunity upon need is evidently allowed by naturally occurring CD4+CD25+ regulatory T cells, which are themselves controlled by brain-derived compounds. These findings challenge widely accepted concepts of the need for discrimination between self and non-self, as they suggest that while such discrimination is indeed required, it is needed not as a way to avoid an anti-self response but to ensure its proper regulation. Whereas a response to non-self can be self-limited by a decreased presence of the relevant antigen, the response to self needs a mechanism for strict control, such as that provided by the naturally occurring regulatory T cells.Received 8 June 2004; accepted 6 July 2004     

CD1d and natural T cells: how their properties jump-start the immune system

Cellular and humoral immune mechanisms recruited to defend the host from infectious agents depend upon the early immune events triggered by antigen. The cytokine milieu within which the immune response matures is the most important of many factors that govern the nature of the immune response. Natural T cells, whose function is controlled by CD1d molecules, are an early source of cytokines that can bestow type 1 or type 2 differentiative potential upon helper T lymphocytes. This review attempts to illuminate the glycolipid antigen presentation properties of CD1d, how CD1d controls the function of natural T cells and how CD1d and natural T cells interact to jump start the immune system. CD1d is postulated to function as a sensor, sensing alterations in cellular lipid content by virtue of its affinity for such ligands. The presentation of a neo-self glycolipid, presumably by infectious assault of antigen-presenting cells, activates natural T cells, which promptly release pro-inflammatory and anti-inflammatory cytokines and jumpstart the immune system. Received 10 July 2000; received after revision 16 October 2000, accepted 16 November 2000     

Protective effect of Shigyaku-to,a traditional Chinese herbal medicine,on the infection of herpes simplex virus type 1 (HSV-1) in mice

The antiviral activity of Shigyaku-to (TJS-109), a traditional Chinese herbal medicine, was investigated in mice infected with herpes simplex virus type 1 (HSV-1). TJS-109 is a combination of the medicinal plant extracts fromZingiberis siccatum rhizoma,Aconiti tuber andGlycyrrhizae radix in a specific proportion. Mice infected with a 10 LD₅₀ dose of HSV-1 were treated with TJS-109 orally at doses of 1.25 to 20 mg/kg 2 days before, and 1 and 4 days after the infection. The treated groups had 80% (1.25 mg/kg), 40% (5 mg/kg) and 23% (20 mg/kg) mortality rates 25 days after the infection as compared with a 100% mortality rate in control mice treated with saline. When HSV-1 infected mice (recipients) received CD8⁺T cell fractions derived from spleens of mice treated with TJS-109 (donors), 70% of recipients survived, as compared with 0% survivors in the groups of mice treated with saline, B cell fractions, CD4⁺ T cell fractions or macrophage-enriched fractions prepared from the same donors. TJS-109 did not show any virucidal activities against HSV-1 or any virostatic activities on the growth of HSV-1 in Vero cells. These results suggest that TJS-109 protected mice exposed to lethal amounts of HSV-1 through the activation of CD8⁺ T cells.     

Retention of atherogenic lipoproteins in atherogenesis

Atherosclerosis is a multifactorial disease whose pathogenesis is still unclear. Mounting evidence, however, supports the concept that subendothelial retention of apoB100-containing lipoproteins is the initiating event in atherogenesis. Subsequently, a series of biological responses to this retained material leads to specific molecular and cellular processes that promote lesion formation.Received 3 July 2003; received after revision 13 August 2003; accepted 15 August 2003     

Glycolipids and phospholipids as natural CD1d-binding NKT cell ligands

Natural killer T (NKT) cells have been shown by a number of studies to play a protective role against cancers, autoimmune diseases and infectious diseases. Several glycolipids and phospholipids derived from mammalian, bacterial, protozoan and plant species have recently been identified as natural ligands (antigens) for NKT cells. Some of these glycolipid/phospholipid ligands have now been crystallized in forms bound to CD1d molecules, and the tertiary structure of these complexes has finally been revealed. This review is intended to list natural NKT cell ligands identified to date, and discuss how their structures relate to their propensity to bind CD1d molecules and, as a consequence, stimulate NKT cells. Received 14 February 2006; received after revision 31 March 2006; accepted 15 May 2006     

靶向CD133的RNA干扰对人肝癌SMMC-7721细胞的生长抑制作用

目的利用RNA干扰技术下调SMMC-7721肝癌细胞中CD133的表达,观察其在肝癌细胞增殖和侵袭方面的作用.方法构建CD133特异性的siRNA真核表达载体,转染SMMC-7721肝癌细胞并筛选出稳定表达siRNA的转染克隆;应用RT-PCR和Western blot检测CD133 mRNA和蛋白的表达;流式细胞仪检...     

Novel estrogen receptor coregulators and signaling molecules in human diseases

The steroid hormone estrogen and signaling from its receptors are increasingly recognized as critical mediators of a variety of organ-specific biological processes. Recent advances in the identification and functional characterization of novel estrogen receptor interacting proteins clearly show the complexity of hormonal signaling regulation, but may also contribute to our understanding of the roles of estrogen signaling in normal physiology and the pathobiology of human disease.Received 12 June 2003; received after revision 21 July 2003; accepted 29 July 2003     

Distribution of HIV-1 in the genomes of AIDS patients

The localization of HIV-1 proviruses in compositional DNA fractions from 27 AIDS patients during the chronic phase of the disease with depletion of CD4+ and different levels of viremia showed the following. (1) At low viremia, proviruses are predominantly localized in the GC-richest isochores, which are characterized by an open chromatin structure; this result mimics findings on HIV-1 integration in early infected cells in culture. (2) At higher viremia, an increased distribution of proviruses in GC-poor isochores (which match the GC poorness of HIV-1) was found; this suggests a selection of cells in which the isopycnic localization leads to a higher expression of proviruses and, in turn, to higher viremia. (3) At the highest viremia, integrations in GC-rich isochores are often predominant again, but generally not at the same level as in (1); this may be the consequence of new integrations from the extremely abundant RNA copies.Received 21 November 2003; received after revision 13 January 2004: accepted 15 January 2004     

Activation of CD47 receptors causes histamine secretion from mast cells

Mast cells play pivotal roles in allergic and inflammatory processes via distinct activation pathways. Mucosal and serosal mast cells are activated by the IgE/FcɛRI pathway, while only serosal mast cells are activated by basic secretagogues. We show that CD47 receptors are expressed on rat peritoneal mast cells. 4N1K, a peptide agonist of CD47, rapidly caused exocytosis. Such exocytosis required increased intracellular calcium and was inhibited by pertussis toxin and an antibody against the βγ dimer of a G_i protein. Cooperation with integrins and glycosylphosphatidylinositol-anchored proteins was necessary, since anti-integrin antibodies and pretreatment with phosphatidylinositol-phospholipase C reduced exocytosis. Depletion of membrane cholesterol inhibited exocytosis and decreased CD47 in lipid rafts, consistent with a CD47/integrin/G_i protein complex being located in rafts. An anti-CD47 antibody inhibited exocytosis induced by 4N1K and by mastoparan and spermine, suggesting that basic secretagogues might target CD47. We propose that 4N1K-stimulated mast cell exocytosis involves a CD47/integrin/G_i protein complex. Received 8 December 2008; received after revision 12 January 2009; accepted 29 January 2009     

RNA干扰CD133基因对结肠癌干细胞生物学行为的影响

目的探讨CD133基因表达、活化被阻断后对结肠癌干细胞生物学行为的影响。方法从EpcAMhighCD44＋结肠癌干细胞中流式分选获得CD133＋细胞,感染LV-CD133shRNA载体慢病毒后观察CD133＋结肠癌干细胞在生长方式、成球能力、克隆形成率、成瘤能力以及ABCC2mRNA的变化;Westernblot分析CD133-细胞中CD133蛋白表达情况。结果EpcAMhighCD44＋结肠癌干细胞中CD133＋细胞比例为89．2％。实验组经过LV-CD133shRNA载体病毒感染后,在干细胞养液中细胞改悬浮生长的方式为贴壁生长,不能形成细胞球。MTT法测定发现细胞增殖减慢,克隆形成率明显下降。将感染细胞移植在Balb／C裸鼠体内,在观察期间,感染LV—CD133shRNA载体病毒的CD133＋细胞无肿瘤形成。ABCG2mRNA表达水平明显降低（P〈0．01）。从EpcAMhighCD44＋结肠癌干细胞中流式分选获得CD133-细胞,其中也有CD133蛋白的表达。结论CD133维持结肠癌干细胞生物学特性。     

无血清分离人结直肠癌细胞的体外培养形态及标志物表达特征

目的探讨人结直肠肿瘤干细胞在体外分化过程中细胞形态和干细胞相关标志物CD133的表达变化,为进一步研究结直肠肿瘤干细胞分化走向提供实验依据。方法取来源于人结直肠癌的细胞系HCT116,无血清培养分离出CD133+细胞,加血清诱导分化,相差显微镜下观察其形态变化;在未分化状态下无血清培养第7天和14天与血清诱导分化后收集细胞,利用流式细胞仪检测干细胞标志物CD133的表达量,采用激光共聚焦检测CD133表面标记分子的表达。结果 1)细胞形态:无血清培养分离的CD133+细胞,在生长过程中聚集成规则的细胞球,血清诱导后即贴壁生长,贴壁形态与同来源细胞形态一致,且再次无血清悬浮培养后聚集成球稳定生长。2)标志物变化:结直肠肿瘤干细胞未分化时CD133表面标记分子高表达,流式细胞仪检测未分化细胞CD133第7天表达率为(20.4±0.52)%,第14天表达率为(78.5±2.80)%,分化后表达率为(0.50±0.17)%。结论细胞形态和标志物表达改变均表明高表达CD133+的HCT116结直肠癌肿瘤干细胞可定向分化为同源的结直肠癌细胞,CD133+细胞经血清诱导后表达下调而使细胞失去干细胞特性。     

PD-L1在人子宫颈癌细胞异常表达并促T细胞凋亡

目的 探讨人子宫颈癌中负性协同刺激分子PD-L1的表达和它与肿瘤浸润淋巴细胞的关系以及PD-L1融合蛋白促宫颈癌患者外周血活化T细胞凋亡的作用.方法 采用免疫组化S-P法检测67例宫颈癌组织及20例正常宫颈组织中PD-L1的表达,分析PD-L1同临床病理特征的相关性,免疫荧光观察肿瘤浸润淋巴细胞数量,TUNEL法检测T细胞凋亡,体外实验将PD-L1融合蛋白细胞加入PHA刺激活化的宫颈癌患者外周血T细胞中共同培养,流式细胞术分析T细胞凋亡率和CD8+/CD4+T细胞比例.结论 正常子宫颈组织不表达PD-L1;宫颈癌组织中PD-L1的表达率为70％.宫颈癌PD-L1的表达与宫颈癌浸润深度相关(P＜0.05).PD-L1阳性病例肿瘤局部浸润淋巴细胞存在凋亡且CD8+T细胞数量明显减少;PD-L1融合蛋白组T细胞凋亡率明显高于抗PD-1组和空白对照组T细胞,分别为32.7％、18.3％和17.9％;CD8+T/CD4+T细胞的比值低于加入抗PD-1组和空白对照组,分别为0.864、0.894和0 907.结论 PD-L1在子宫颈癌中高表达且与肿瘤浸润程度及肿瘤浸润淋巴细胞数量减少有关,PD-L1能促进活化的T细胞尤其是CD8+T细胞的凋亡.     

Polyisoprenyl glycolipids as targets of CD1-mediated T cell responses

T cells are well known to recognize peptide antigens presented by major histocompatibility (MHC) class I or class II molecules. More recently, the CD1 family of antigen-presenting molecules has been shown to present both mammalian and microbial glycolipid antigens for specific recognition by T cells. Human CD1c proteins mediate T cell recognition of polyisoprenyl glycolipids, evolutionarily conserved phosphoglycolipids, which function in glycan synthesis pathways. This family of antigenic molecules is particularly attractive for the study of the molecular features that control T cell recognition of self and foreign glycolipids because natural polyisoprenols from mammals, fungi, protozoa, mycobacteria and eubacteria differ in structure. Moreover, these naturally occurring structural differences can influence their recognition by CD1c-restricted T cells. This review of the structural diversity and evolutionary relationships of polyisoprenoid glycolipids emphasizes those features of polyisoprenyl glycolipid biosynthesis that are relevant to their functions as targets of CD1-mediated T cell responses. Received 16 March 2001; received after revision 19 April 2001; accepted 23 April 2001     

Distinct features of recombinant rat vanilloid receptor-1 expressed in various expression systems

In this study, we expressed rat vanilloid receptor 1 (VR1) in various heterologous expression systems using different VR1-encoding vectors, and examined how the VR1 agonists capsaicin and resiniferatoxin affected intracellular calcium. Our results clearly show that the magnitude and kinetics of response as well as the extent of tachyphylaxis differ markedly between systems. Using green fluorescent protein-tagged VR1, we show that much of the VR1 is localized to intracellular membranes. Consistent with this localization, VR1 agonists are able to liberate calcium from intracellular stores in the absence of extracellular calcium. As with other parameters of response, the three expression systems differ in the degree to which, in the absence of extracellular calcium, capsaicin and resiniferatoxin can liberate calcium from the intracellular stores. Our findings emphasize the influence of the expression system on characteristics of the response of VR1 to its ligands and the need for caution in extrapolating such results to other settings.Received 16 June 2003; received after revision 26 July 2003; accepted 31 July 2003