Th17细胞分化、调节及效应研究进展

Th17细胞作为一个不同于Th1、Th2的细胞亚群,已经被证实在自身免疫病、感染等疾病中发挥重要的作用.为了进一步认识Th17细胞的效应机制,近来对于Th17细胞的分化及调节进行了深入的研究,证实TGF-β与IL-6或者IL-21的协同作用是诱导Th17细胞分化的关键因素,而IL-23在促进IL-17分泌,增强Th17细胞效应功能方面发挥重要作用.与Th1、Th2、Treg细胞特异性的转录调节因子T-bet、GATA3、Foxp3相对应,现证实ROR-γt(retinoid-related orphanreceptors-γr)是促进Th17细胞分化、调节其功能的特异性转录调节因子.Th17细胞通过分泌IL-17A、IL-17F、IL-21、IL-22、IL-6、TNF-α等细胞因子发挥效应功能.其中IL-21作为Th17细胞的一个自分泌调节凶子,在诱导Th17分化、抑制Th1、Treg功能方面发挥关键作用.而另一方面,近来发现,重要的T细胞生长因子IL-2在维持、促进Th1、Th2、Treg及CD8 T细胞功能活性的同时,却发挥着抑制Th17细胞分化的作用.Th1、Treg、Th17细胞的分化之间存在微妙的调节关系,TGF-β的水平、作用的时间决定着上述三群T细胞的分化结局.Th17细胞与Th1细胞均是自身免疫病及感染性疾病的重要效应细胞,二者的作用是否有时间、空间、功能方面的特异性?TGF-β如何调节两群效应细胞的分化方向及功能?以及Th17细胞在体内免疫平衡中的作用,是否可以通过Th17细胞诱导免疫耐受等,是人们急于回答的非常有意义的课题.     

IL-23/Th17轴在变应性哮喘中的研究进展

变应性哮喘是一种由辅助性T细胞（T helper cell,Th cell）调节的慢性炎症性疾病。Th1/Th2的失衡一直被认为是变应性哮喘的发病机制,Th2细胞及其分泌的细胞因子白介素4（interleukin 4,IL-4）、IL-5以及IL-13在变应性哮喘特异性症状的发病中发挥重要作用。最近研究发现Th17细胞及其分泌的IL-17参与变应性哮喘的发展过程,IL-23在Th17细胞维持生存和功能成熟中发挥重要作用,并参与抗原诱导的气道炎症反应。该文对目前IL-23/Th17轴在变应性气道炎症反应中的研究进展作一综述。     

白介素6与肿瘤相关性的研究进展

白介紊-6(interleukin 6,IL-6)是一种由多种细胞产生的多功能细胞因子,在免疫应答、急性期反应、造血调节中起重要作用.最近研究发现IL-6与肿瘤的发生发展、预后及治疗密切相关.本文主要介绍IL-6的结构、生物学功能、及其与肿瘤的关系.探讨其在肿瘤发生发展中的作用机制及在肿瘤的早期诊断,预后和治疗方面的应用前景.     

白细胞介素18

白细胞介素-18(IL-18)是新发现的细胞因子,具有多种生物学功能.IL-18能促进外周血单个核细胞产生干扰素-γ(IFN-γ)、IL-2、粒细胞巨噬细胞集落刺激因子(GM-CSF)等细胞因子,增强天然杀伤细胞(NK细胞)的细胞毒作用.IL-18结构上与IL-1相似,而功能更接近IL-12,IL-18与IL-12均能诱导Th1细胞产生IFN-γ,存在协同效应,但它们的作用途径不同.IL-18在抗感染抗肿瘤等方面有着潜在的应用前景,并与自身免疫性疾病的发病密切相关.     

白细胞介素33在肿瘤免疫中的作用及信号通路研究进展

白细胞介素33(interleukin-33,IL-33)主要表达于人角质细胞、内皮细胞和纤维母细胞中。IL-33在Th(helper T cell)2细胞的成熟中发挥重要作用,促进Th2细胞分泌Th2相关细胞因子,趋化Th2细胞,并在组织损伤中作为警报素放大免疫反应。IL-33也可以激活肥大细胞、嗜碱性粒细胞、嗜酸性粒细胞和自然杀伤细胞。随着肿瘤免疫疗法研究逐渐深入,IL-33的抗肿瘤作用也逐渐被人们认识,包括在黑色素瘤和乳腺癌等癌症中的作用。为更好总结IL-33在肿瘤免疫中的研究进展,本文从IL-33在肿瘤免疫中的信号通路和IL-33对不同肿瘤免疫治疗效应两方面进行了归纳和总结。     

IL-17在肿瘤发生发展中的作用

Th17作为新发现的一类Th细胞亚群,其分泌的IL-17在肿瘤的发生与发展过程中有着重要的作用。大量文献报道IL-17在肿瘤发生发展过程中发挥双刃剑的作用,一方面,IL-17可以通过促进血管生成和肿瘤细胞的迁移促进肿瘤的生长。另一方面,IL-17亦可促进细胞毒性T细胞的免疫应答抑制肿瘤的生长。     

Th17细胞的分化、调节及其主要细胞因子和功能

近几年来以分泌白介素17(interleukin 17,IL-17)为特征的辅助性T细胞Th17(T help cell 17,Th17)细胞被认为是有区别于Th1(T help cell 1,Th1)、Th2(T help cell 2,Th2)新型的细胞亚群,它的发现改变了以往人们只将Th细胞分为Th1、Th2的传统分类认识。Th17细胞参与了自身免疫疾病、肿瘤的发生及机体各种炎症的发病机制,其分泌的细胞因子在生物学功能中发挥了极其重要的作用。同时Th17细胞的活化需要各种转化生长因子、IL-6(interleukin 6,IL-6)、IL-23(interleukin 23,IL-23)等细胞因子的参与,活化的Th17细胞同时再进一步的促进各种细胞因子的分泌,以通过分泌IL-17、IL-21(interleukin 21,IL-21)、IL-22(interleukin22,IL-22)、IL-26(interleukin 26,IL-26)、肿瘤坏死因子(tumor necrosis factor,TNF)α等细胞因子导致机体炎症等各种疾病的发生。     

Th17分化调节机制及其在器官移植中的研究进展

Th17细胞是新近发现的第三类CD4+ T辅助细胞亚群,其所分泌的IL-17、IL-22等细胞因子在中性粒细胞趋化、组织重塑与修复及介导抗体蛋白的产生等具有重要作用.但Th17分化调节受外界环境影响较大,如转录因子、细胞因子、Th1、Th2和调节T细胞(Tregs)等,这些均具有决定初始CD4+ T细胞向Th17细胞的分化方向和免疫反应方向的调控作用.目前Th17在器官移植物免疫耐受中的作用越来越受到重视,明确Th17分化调节的各种影响因素,将为器官移植免疫耐受研究提供新思路.     

辅助性T细胞17在免疫相关性全血细胞减少症中的免疫调节功能研究

免疫相关性全血细胞减少(immune-related pancytopenia,IRP)是临床多个学科易见的疾病,也是困扰临床医师的一大难题。近年来关于辅助性T细胞17(T helper 17,Th17)对IRP发病作用的研究更是热点。通过检测免疫相关性全血细胞减少症患者骨髓中Th17细胞数量及功能变化,探讨Th17细胞在IRP中的免疫调节作用。研究发现,IRP患者(IL-23R)+CD4+/CD4+细胞比率及其骨髓上清液IL-6、IL-17、IL-23水平增高,提示IL-23介导的Th17细胞分化亢进可能是IRP发病原因之一。免疫干预治疗可以显著降低Th17细胞比率及IL-23R,抑制Th17细胞分化亢进可能是治疗IRP的一个靶点。     

Th17细胞分化和功能的研究进展

近年研究发现了效应性辅助性T细胞的新亚群-Th17细胞,它主要分泌IL-17、IL-17F、IL-21和IL-22等细胞因子。Th17细胞及其效应分子被认为与自身免疫病和其他多种疾病相关。该文从Th17细胞的发现、人和小鼠Th17细胞的分化、Th17细胞的效应性因子及与健康和疾病的相关性几个方面对目前的研究进展进行了综述。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.