白细胞介素—2活化DNA结合因子的研究

用凝胶阻滞分析的方法,发现鼠Ｔ淋巴细胞系ＣＴＬＬ－２在白细胞介素－２（ＩＬ－２）刺激下可活化一个结合因子,它与γ－干扰素活了列（ＧＡＳ）专一性结合,命名这个ＤＮＡ结合因子为白细胞介素－２活化核因子（ＩＬ－２－ＮＡＦ）,ＩＬ－２－ＮＡＦ的活化非常迅速,不需要新的蛋白质合成,并且它的活化程度随着ＩＬ－２刺激细胞的时间的不同而发生相应的变化,进一是步研究表明,ＩＬ－２－ＮＡＦ的活化过程是通过酪氨酸激酶的     

PTPase对IL-2信号转导通路的正调和负调作用

用蛋白质酪氨酸磷酸酯酶(PTPase)抑制剂正矾酸钠处理细胞,可以大为增强细胞内蛋白质的酪氨酸磷酸化水平.电泳迁移率变动分析(EMSA)发现,此时Stat5发生酪氨酸磷酸化而被激活,并与γ-干扰素活化序列(GAS)结合.与白细胞介素-2(IL-2)活化Stat5不同,正矾酸钠对Stat5的活化不能被蛋白质酪氨酸激酶(PTK)抑制剂完全阻断.此外发现,正矾酸钠可以加强IL-2对启动子区含有GAS的报告基因表达的上调作用.以上结果证明PTPase对IL-2诱导的JAK-STAT信号转导通路起负调作用.然而,抑制PTPase的活性却可以阻断IL-2对TNF-β基因和c-myc基因转录的激活,并导致细胞死亡.因此,PTPase在IL-2诱导的不同信号转导通路中分别起正调和负调作用,这两种作用都是通过它的酯酶活性来实现的.     

基因工程人白细胞介素－2的生物功能研究

重组白细胞介素－2(rIL－2),能维持T－淋巴细胞及CTLL-2细胞株(IL-2依赖)的增殖达一个月之久,细胞总数增加了近千倍。这种作用能被rJL-2专-的单克隆抗体破坏,显示rIL-2的专一性,rIL-2能增加天然杀伤细胞(NK)的活动达46—96％,但其剂量太高时反而起抑制作用,它能诱异淋巴因子激活的杀伤细胞(Lvmphokine Activated Killier,LAK)的生成,它还能杀伤转移性人肺癌细胞及抗NK的HL－60癌细胞株,其杀伤效率达37.06—54．84％。这说明我们获得的rIL－2在上述生物功能方面与天然lL－2相似。     

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.     

人白细胞介素-2结构与镇痛功能关系的研究

免疫调节因子白细胞介素-2(IL-2)具有中枢镇痛功能。实验采用基因定位突变技术,获得系列IL-2突变体,并测定其免疫学活性和镇痛能力,发现无免疫学活性的IL-2突变体20Leu-IL-2仍具有中枢镇痛能力,而44Leu-IL-2,45 Val-IL-2虽保留了免疫学活性,但其镇痛能力显著性下降或消失,阿片受体拮抗剂纳洛酮能够阻断IL-2的中枢镇痛作用,而不能影响IL-2对CTLL-2细胞的增殖作用。抗内源性阿片肽血清与IL-2能发生明显的交叉反应。实验结果提示,IL-2分子是通过由第45位Tyr残基及空间上相近的Phe残基等组成的镇痛功能位点与阿片受体相结合而发挥镇痛效应。     

人白细胞介素－2的两个部分拮抗剂

通过定点诱变技术得到6个生物活性剧烈下降的人白细胞介素-2(IL-2)突变体,其中两个突变体即15Val-IL-2和126Asp-IL-2可以在一定浓度范围内使IL-2的生物效应降低.在对高亲和力IL-2受体(IL-2R)的竞争抑制实验中,15Val-IL-2和126Asp-IL-2又表现了一定的竞争能力.这些结果表明15Val-IL-2和126Asp-IL-2的部分拮抗天然IL-2的作用.结合IL-2二级结构分析及对IL-2与IL-2R相互作用的已有认识,可认为15Val-IL-2和126Asp-IL-2的部分拮抗作用产生的原因在于替换残基在空间上对IL-2与IL-2R βγ亚基结合微环境的轻微扰动,干扰了IL-2有关残基与IL-2R βγ亚基的结合,但尚不能完全阻止其与IL-2R βγ亚基的结合.     

白细胞介素-2加强小鼠T淋巴细胞产生白细胞介素-3

本文报道了白细胞介素-2(IL-2)刺激ConA(5μg/ml)活化的小鼠T细胞产生的条件培养液(TCM)中含有CFU-GEMM诱导活性。这种CFU-GEMM诱导活性的生成在IL-2作用后48h达到高峰。特异性抗IL-3单克降抗体可以完全中和该条件培养液中的CFU-GEMM诱导活性。进一步证明,TCM可以刺激IL-3依赖细胞系FDC-P_1细胞的增殖;在IL-2作用于ConA活化的T细胞后可促进其细胞表达高水平的IL-3mRNA。这些结果表明IL-2可以加强小鼠T细胞产生IL-3。     

丹参酮Ⅱ-A对细胞因子IL-6和IL-10的影响

目的:RAW264.7细胞中,炎症发生时相关的细胞炎症因子白细胞介素-6(IL-6)和白细胞介素-10(IL-10)起重要作用.丹参酮Ⅱ-A是传统中药丹参的一种重要的药理成分,它具有一定的抑制炎症的作用.但是,从传统中药丹参提取液中的丹参酮对炎症过程的影响研究较少.该文着重介绍了丹参酮Ⅱ-A在转录水平上对IL-6和IL-10的调节作用.方法:以RAW264.7细胞系作为药物刺激靶细胞,使用不同浓度的丹参酮Ⅱ-A对其进行刺激,分别刺激24h、48h后,半定量RT-PCR检测IL-6和IL-10mRNA表达量的变化.结果:丹参酮Ⅱ-A可以诱导IL-10的释放,同时也减少IL-6的生成,说明它对炎症因子有一定的调控作用.结论:在炎症发生后,丹参酮Ⅱ-A可有效的调节炎症因子的mRNA表达量,进而减少或消除炎症.     

细胞素与艾滋病的体外实验结果引起疑问

近期研究体内四种造血生长因子及γ-干扰素对受HIV-1侵染的人体单核吞噬细胞的影响,它们给临床应用蛋白质治疗艾滋病带来一些问题。特别是洛杉矶加利福尼亚大学(UCLA)医学院的研究者发现当往HIV-侵染的培养细胞中加入粒细胞-巨噬细胞集落刺激因子(GM-CSF)、巨噬细胞集落刺激因子(M-CSF)或白细胞介素-3(IL-3)时,     

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.