miRNA在衣原体感染中的作用

衣原体是一种专性胞内寄生的原核细胞型微生物,是感染人和动物常见的病原体之一,能引起人类和动物罹患多种疾病。miRNA是一类内源性非编码单链RNA分子,在细胞的增殖与分化、自噬与凋亡、病毒感染等生理和病理过程中发挥重要作用。近年来相关研究发现,衣原体感染后能引起宿主的miRNA表达水平发生改变,其不仅调节宿主细胞线粒体网络结构进而影响衣原体的生长发育,还作为区分不同衣原体变体引起感染的早期生物标志物。miRNA参与了衣原体感染过程的调控,但miRNA在衣原体感染中的作用机制尚不完全清楚。本文就miRNA在衣原体感染中的作用进行简要综述。     

γδT17细胞活化机制的研究进展

IL-17是一种重要的促炎细胞因子，在炎症性疾病和自身免疫性疾病中发挥重要作用。研究发现，除Th17细胞外，γδT17细胞也是IL-17的重要来源。γδT17细胞参与多种免疫应答过程，与感染性疾病、自身免疫性疾病和肿瘤等疾病的发生发展密切相关，本文综述γδT17细胞活化机制的研究进展，探明γδT17细胞的分化和活化机制将为上述疾病的治疗提供新思路。     

Th17细胞在肺部感染免疫中的作用

Th17细胞是近年来发现的一种新的效应T细胞亚群,在自身免疫性疾病和感染中发挥重要的作用,其分泌产生几种致炎细胞因子,包括新发现的细胞因子白细胞介素17。Th17产生的细胞因子与Th1、Th2不同并且与其相互对抗。Th17细胞很可能对防御胞外病原菌的感染及自身免疫性疾病产生影响。综述了Th17细胞产生的细胞因子及其在肺部感染免疫中的作用相关方面的进展。     

CD8~+T细胞抗衣原体感染研究进展

衣原体(Chlamydia)是一种重要的胞内致病菌,其感染可引起多种疾病并常导致并发症。在衣原体感染过程中,宿主多种细胞参与免疫调控以抵抗衣原体的感染。CD8~+T细胞通过其跨膜受体(T cell receptor,TCR)识别抗原,从而在T细胞介导的抗衣原体感染中发挥了至关重要的作用,其抗感染机制可能与分泌细胞因子有关。现就CD8~+T在衣原体感染过程中的产生、募集、应答机制以及所介导的免疫病理反应作一概述,旨在为衣原体疫苗研制提供新的思路。     

衣原体免疫逃逸机制的研究进展

衣原体是一类专性细胞内寄生的原核细胞型微生物,感染人体后可引起多种慢性疾病。衣原体在宿主细胞中复制和持续性存在是其致病的主要原因。近年的研究表明,衣原体通过改变MHC抗原表达、干扰宿主细胞凋亡信号通路等机制以逃逸宿主的免疫清除。     

Th17细胞在侵袭性烟曲霉病中双向调节作用的研究进展

辅助性T细胞17(Th17)在机体侵袭性肺烟曲霉病中有防御和破坏性作用,一方面经常可以观察到曲霉菌感染后Th17细胞数量的增加,IL-17水平升高、或者Th17细胞促稳定因子IL-23的升高,其机制可能为分泌特异的细胞因子、介导自身免疫反应或者趋化效应性T细胞等几个方面;另一方面体内Th17细胞免疫反应可导致免疫损伤,其机制中主要包含直接作用和间接作用两种,直接作用表现为IL-17在体内外均可以促进烟曲霉生长,间接作用表现为IL-17可通过上调促炎介质、抑制Th1免疫反应或促进Th2免疫反应等机制促进炎症发生发展。Th17细胞对侵袭性肺烟曲霉病的这种双向调节作用主要与烟曲霉与感染环境如宿主免疫状态、感染时间、真菌细胞壁的特异成分的相互作用等有关。     

衣原体逃逸宿主免疫反应机制研究进展

衣原体感染常表现为持续性感染,能够引起人和动物的多种慢性疾病。衣原体成功逃逸宿主免疫反应是其维持持续感染的前提,目前已知衣原体可通过逃避宿主细胞溶酶体融合、调控宿主细胞免疫反应、干扰宿主细胞凋亡与自噬活动以及诱导宿主细胞蛋白质组改变等方式逃逸宿主免疫反应。现就衣原体逃逸宿主免疫反应的相关研究作一综述。     

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、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.     

Th17/Treg 细胞在银屑病的发病机制研究进展

Th17细胞和Treg细胞是CD4+T细胞在不同细胞因子环境中分化出的新亚群,发挥不同的生物学效应,使机体的免疫系统处于平衡状态.Th17/Treg细胞失衡可引起一系列自身免疫性疾病.银屑病是与遗传、免疫异常有关的皮肤炎症性疾病,其发病机制尚不清楚.越来越多的研究发现,Th17细胞增多和Treg细胞减少及其分泌的细胞因子在银屑病的发病中有着重要作用.本文围绕这一机制综述了近年来有关Th17细胞、Treg细胞在银屑病发病机制中作用的研究,帮助我们更深入地了解银屑病的发病机制并为今后临床诊断和治疗提供依据.     

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.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

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.