首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
浆细胞样树突状细胞(PDC)来源于淋巴系干细胞,其表面标志、功能有别于髓系DC,不仅在抗病毒免疫中发挥重要作用,而且通过多种途径诱导T细胞失能和调节性T细胞的形成,从而参与免疫耐受的诱导.PDC诱导T细胞免疫耐受的分子机制与吲哚胺2,3-双加氧酶(IDO)-色氨酸代谢通路和具有抑制功能的膜分子密切相关.深入阐明PDC诱导耐受的机制,将为免疫耐受异常相关的疾病的治疗提供新方案.  相似文献   

2.
张荣  洛若愚 《国际免疫学杂志》2006,29(2):123-125,128
可溶性人白细胞抗原(sHLA)Ⅰ在体内参与免疫应答,可诱导产生免疫耐受,抑制细胞毒性T淋巴细胞(CTL)的溶细胞作用。在器官组织移植、感染性疾病、自身免疫性疾病及肿瘤分化中具有重要的免疫调节作用。  相似文献   

3.
可溶性人白细胞抗原(sHLA)-Ⅰ在体内参与免疫应答,可诱导产生免疫耐受,抑制细胞毒性T 淋巴细胞(CTL)的溶细胞作用.在器官/组织移植、感染性疾病、自身免疫性疾病及肿瘤分化中具有重要的免疫调节作用.  相似文献   

4.
树突状细胞和免疫耐受   总被引:1,自引:0,他引:1  
树突状细胞(DC)是职业抗原递呈细胞,即可触发排斥反应,又能够调节T细胞反应而产生外周免疫耐受。尽管其诱导外周免疫耐受的确切机制尚不清楚,但DC在诱导供体特异性T无反应细胞(Treg)凋亡,供体特异T调整细胞,转基因诱导耐受DC以及T辅助细胞转化方向等方面都取得了明显进展。进一步研究DC在诱导自身抗原耐受的作用机理,可以揭示DC诱导移植免疫耐受,以实现人类在不依赖免疫抑制剂的条件下产生供体特异性免疫耐受,本文拟就有关内容作一综述。  相似文献   

5.
浆细胞样树突状细胞(p DC)是一种功能较为特殊的DC,可以通过胞质内Toll样受体(TLR)识别病毒RNA或细菌非甲基化DNA,产生大量1型干扰素,参与抗病毒免疫过程,同时p DC可以提呈抗原给T细胞,诱导CD8+细胞毒T细胞和CD4+效应T细胞分化并决定其反应类型,是联系固有免疫和适应性免疫的重要细胞。p DC的共刺激分子表达谱与经典的DC(c DC)不同,其活化性共刺激分子表达较少,刺激T细胞免疫反应的能力较弱,有利于诱导CD4+或CD8+调节性T细胞,对于诱导和维持免疫耐受具有十分关键的作用,在自身免疫性疾病和器官移植中有非常重要的应用前景。本文综述了p DC的发生、发育和功能特点以及近年来在诱导免疫耐受方面的研究进展。  相似文献   

6.
浆细胞样树突状细胞(pDC)是一类近年来被认识并证明在免疫应答与免疫耐受中发挥重要作用的免疫细胞,其功能特点在于活化后大量快速分泌Ⅰ型IFN,并能够通过Ⅰ型干扰素途径增强自然杀伤细胞(NK细胞)、T淋巴细胞、B淋巴细胞以及树突状细胞(DC)的功能,之后分化为一类独特的成熟DC,参与调节T细胞功能,从而有效地连接了固有免疫和适应性免疫.  相似文献   

7.
不同亚群CD8+T细胞细胞毒作用对慢性乙型肝炎的影响   总被引:1,自引:0,他引:1  
目的观察慢性乙型肝炎不同分期及干扰素-a(interferon-a,IFN-a)治疗前后外周血不同亚群CD8+T细胞细胞毒作用的变化,探讨其在慢性乙型肝炎发病机理及抗病毒治疗中的作用。方法采集20例慢乙肝免疫耐受期患者和20例免疫清除期患者IFN—a治疗前后的外周全血,采用流式细胞仪检测CD8^high和CD8^lowT细胞的颗粒酶B(Granzyme B,GrB)和溶酶体相关膜蛋白-1(Lysosome—associated membrane protein.1,LAMP-1,CD107a)表达变化,并进行分析。结果(1)慢乙肝患者免疫清除期不同亚群CD8+T细胞GrB和CD107a的表达水平均高于免疫耐受期;(2)不同分期慢乙肝患者CD8^lowT细胞GrB和CD107a的表达水平均高于CD8^highT细胞;(3)IFN—a治疗后CD8^highT细胞的GrB和CD107a表达水平和治疗前相比具有升高趋势,而CD8^lowT细胞反而具有下降趋势;(4)不同亚群CD8+T细胞的GrB和CD107a表达水平与HBV—DNA载量在免疫耐受期呈正相关,而在免疫清除期呈负相关。结论(1)不同亚群CD8+T细胞的GrB和CD107a分子在慢乙肝疾病进程及抗病毒治疗中均起重要作用,CD8^lowT细胞的细胞毒作用强于CD8^highT细胞,而CD8^highT细胞的细胞毒效应在IFN—a治疗过程中逐渐增强。(2)不同亚群CD8+T细胞的GrB和CD107a分子水平与HBV病毒载量的相关性在一定程度上可以提示机体免疫应答与病毒之间的关系。  相似文献   

8.
浆细胞样树突状细胞(pDC)是一类在病毒入侵时分泌Ⅰ型IFN并介导细胞免疫应答的抗原提呈细胞,除了启动获得性免疫应答,它们在扩增调节性T细胞及介导免疫耐受方面也发挥着重要的作用。结合最新研究,此文着重介绍pDC诱导、扩增调节性T细胞及其介导免疫耐受的分子机制,并对pDC来源在介导耐受中的作用进行了介绍,其对于免疫耐受的影响与受者所处的免疫环境、免疫效应发生部位密切有关。深入研究pDC与移植免疫耐受间的密切联系将有助于探讨临床细胞免疫治疗的更多可能性。  相似文献   

9.
TRIM(tripartite motif)蛋白是一类含有RING结构域的蛋白质,在人类中发现超过70种,还有许多新成员正在研究中.这类蛋白除了参与细胞增殖、分化、发育、形态发生和细胞凋亡.也在免疫相关信号通路和抗病毒免疫反应中发挥重要作用.TRIM25能够泛素化病毒RNA受体视黄酸诱导基因-Ⅰ(RIG-Ⅰ)的N末端,这种改变能够激活RIG-Ⅰ与其下游配体结合参与线粒体抗病毒信号通路(MAVS).这个过程直接引起I型干扰素(IFN)的产生从而抑制病毒复制.近来的研究发现甲型流感病毒能够靶向结合TRIM25,使其抗病毒的功能失效从而抑制宿主的干扰素活性.本文对TRIM蛋白在抗病毒防御机制中的功能以及一种流感病毒通过靶向结合某种TRIM蛋白而产生的免疫逃逸机制的研究进展进行总结.  相似文献   

10.
机体免疫系统维持对自身物质的免疫耐受、防止自身免疫性疾病发生的机制非常复杂。尽管胸腺能触发自身反应性T细胞的清除,但胸腺内仍有多种组织特异的蛋白表达量较少而不足于诱导自身耐受。机体也存在胸腺外耐受,如树突细胞(DCs)等抗原递呈细胞(APCs)可从其它细胞捕获自身抗原再传递给自身反应性T细胞(间接递呈),使后者缺失或无能而形成免疫耐受;或APCs由于不完全成熟而使得自身反应性T细胞仍具部分活性。因此,给予APCs成熟信号可能打破胸腺外T细胞的免疫耐受而诱发自身免疫性疾病。  相似文献   

11.
Renal dysplasia and asplenia in two sibs   总被引:2,自引:0,他引:2  
A family is reported in which two sibs, one male and the other female, both died within 24 hours of birth with enlarged polycystic kidneys. Postmortem histology in the second child showed gross renal dysplasia. In both children the pancreas was enlarged, nodular and cystic but the liver appeared macroscopically normal. In the second child, histological examination confirmed pancreatic fibrosis with cystic dilation of ducts, but showed portal fibrosis with bile duct proliferation in the liver.
This combination of findings is very reminiscent of those in a girl and her brother reported by Ivemark et al. (1959). The children reported here also showed absence or hypoplasia of the spleen, cardiac anomalies and other features of the Ivemark syndrome (Ivemark 1955), a quite different, usually sporadic, congenital disorder. It is suggested that the children described here have a distinct lethal congenital disorder, probably inherited in an autosomal recessive manner.  相似文献   

12.
Over 200 schizophrenic patients belonging to three major and interrelated pedigree complexes have been investigated over the past 30 years in a North Swedish geographically isolated population, presently numbering about 6,000. An intensive investigation of a number of biochemical correlates and genetic markers in a few selected families belonging to one of the major pedigrees has indicated new strategies for the current research program.
Schizophrenia, as defined operationally, is significantly associated with decreased activities of two enzymes (1) blood platelet monoamine oxidase, (2) plasma dopamine-β-hydroxylase, and (3) with the genetic marker Gc2 (group specific antigen). Both enzymes are subject to genetic variation. A positive score for linkage between schizophrenia and low plasma DBH activity has been calculated, but, so far, available data are insufficient for discrimination between linkage and partial contribution of genetically controlled low plasma DBH to the pathogenesis of the disease. Alternatively, both mechanisms could be involved.
As a model for continued research, schizophrenia is explained as based on a double dominant-recessive genotype (Aabb), representing a vulnerability which in about 50 % of cases develops into clinical schizophrenia. It is suggested that the dominant mutation (A) operates on or affects MAO activity, and that the recessive genotype (bb) is instrumental in low variates of DBH activity and very likely such variates within the normal range of physiological variation. Moreover, it is suggested that the combined effects of MAO- and DBH-reduced efficiency on the metabolism of e.g. dopamine could be an essential pathogenic mechanism for the schizophrenic illness which is segregating in this population.  相似文献   

13.
About 1900, modern food selection and processing caused widespread epidemics of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a panhypovitaminosis B, i.e., a mixture of substrate beriberi and substrate pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse endemic disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for primates. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.  相似文献   

14.
15.
There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub-Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide-treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.  相似文献   

16.
Newton H 《Medical history》2011,55(2):153-182
Sick children were ubiquitous in early modern England, and yet they have received very little attention from historians. Taking the elusive perspective of the child, this article explores the physical, emotional, and spiritual experience of illness in England between approximately 1580 and 1720. What was it like being ill and suffering pain? How did the young respond emotionally to the anticipation of death? It is argued that children’s experiences were characterised by profound ambivalence: illness could be terrifying and distressing, but also a source of emotional and spiritual fulfilment and joy. This interpretation challenges the common assumption amongst medical historians that the experiences of early modern patients were utterly miserable. It also sheds light on children’s emotional feelings for their parents, a subject often overlooked in the historiography of childhood. The primary sources used in this article include diaries, autobiographies, letters, the biographies of pious children, printed possession cases, doctors’ casebooks, and theological treatises concerning the afterlife.  相似文献   

17.
Recent advancements in agricultural biotechnology have created a need for analytical techniques to determine introduced proteins in crops enhanced through modern biotechnology techniques. These proteins are expressed in plant tissues and may be present in food ingredients. Immunoassays are ideally suited for protein detection and may be used as both quantitative and threshold methods. Microplate ELISA and lateral flow devices are two of the most commonly used immunoassay formats for agricultural biotechnology applications. This paper provides general background information and a discussion of criteria for the validation and application of immunochemical methods to the analysis of proteins introduced into plants and food ingredients using biotechnology methods. It is the result of a collaborative effort of members of the Analytical Environmental Immunochemical Consortium. This collaborative effort represents the combined expertise of several organizations to reach consensus on establishing guidelines for the validation and use of immunoassays. Further, the paper offers developers and users a consistent approach to adopting the technology as well as aid in producing accurate and meaningful results.  相似文献   

18.
The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis. The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed. Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology. Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts.  相似文献   

19.
HLA-A,-B,-C,-DRB1 and -DQB1 alleles have been studied in Chimila Amerindians from Sabana de San Angel (North Colombian Coast) by using high resolution molecular typing. A frequent extended haplotype was found:HLA-A*24:02-B*51:10-C*15:02-BRB1*04:07-DQB1*03:02 (28.7%) which has also been described in Amerinndian Mayos Mexican population (Mexico, California Gulf, Pacific Ocean). Other haplotypes had already been found in Amerindians from Mexico (Pacific and Atlantic Coast), Peru (highlands and Amazon Basin), Bolivia and North USA. A geographic pattern according to HLA allele or haplotype frequencies is lacking in Amerindians, as already known. Also, five new extended haplotypes were found in Chimila Amerindians. Their HLA-A*24:02 high frequencies characteristic is shared with aboriginal populations of Taiwan; also, HLA-C*01:02 high frequencies are found in New Zealand Maoris, New Caledonians and Kimberly Aborigines from Australia. Finally, this study may show a model of evolutionary factors acting and rising one HLA allele frequency (-A*24:02), but not in others that belong to the same or different HLA loci.  相似文献   

20.
There is a sharp difference in how one views TCR structure–function–behaviour dependent on whether its recognition of major histocompatibility complex‐encoded restriction elements (R) is germline selected or somatically generated. The generally accepted or Standard model is built on the assumption that recognition of R is by the V regions of the αβ TCR, which is not driven by allele specificity, whereas the competing model posits that recognition of R is allele‐specific. The establishing of allele‐specific recognition of R by the TCR would rule out the Standard model and clear the road to a consideration of a competing construct, the Tritope model. Here, the case for allele‐specific recognition (germline selected) is detailed making it obvious that the Standard model is untenable.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号