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It has long been recognized that T·T mismatches can adopt two different modes of exchangeable wobble base pairs in which no preferential pairing mode has been observed. In this study, we have performed a systematic nuclear magnetic resonance (NMR) investigation to study the sequence context effect on the pairing modes of T·T mismatches. Our results reveal for the first time that preferential pairing mode does exist in T·T mismatches with specific type of flanking base pairs. 相似文献
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Summary The -glucuronidase staining characteristics of isolated T cell populations and the T and T enriched fractions derived of them were studied. T lymphocytes were obtained from purified T lymphocytes by ox-IgG rosette sedimentation. The rosette-forming cells in the pellet were referred to as T lymphocytes, whereas the lymphocytes in the interface were referred to as T depleted or T lymphocytes. B cells were studied on rosetted mononuclear cells with either mouse erythrocytes or with Staphylococcus Aureus (Cowan I) bacteria, after a preceeding polyvalent anti-human Ig treatment of the cells. While B cells showed mostly no reactivity, T and T cells were respectively characterised by a dot-like and granular pattern of reactivity. These findings are in agreement with those observed by others after -naphthyl-acetate esterase or acid phosphatase staining. Within the T lymphocyte fraction, the T non-, non lymphocytes seemed to have a granular pattern of reactivity. The same staining pattern was found in non-B, non-T lymphocytes. 相似文献
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《生物产业技术》2017,(5)
T细胞受体工程T细胞疗法(TCR-T)是肿瘤治疗中很有希望的一种特异性过继性细胞免疫疗法,该方法主要是将肿瘤抗原特异的TCR基因通过载体转入自体的淋巴细胞中,再回输至病人体内以达到杀伤肿瘤细胞的目的。目前对TCR-T的挑战是肿瘤抗原特异的高亲和性的TCR基因的获取和高度表达以及TCR双链α和β的正确配对。除此之外,通过临床试验已经发现,由于TCR的高反应性,TCR-T会在靶向肿瘤细胞表面抗原的同时作用于正常组织而产生强的脱靶效应,因此,选择合适的靶抗原也是TCR-T细胞治疗能够发挥其优越效果的关键因素。对TCR基因的表达和调节机制、TCR配对的优化战略等TCR-T在肿瘤治疗中面临的挑战,以及TCR-T的临床转化和应用价值进行了探讨。 相似文献
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<正>前言 1979年高月等发现成人T细胞白血病(ATL),指出是以日本冲绳,南九洲,四国,纪伊和三陆,以及加勒比海沿岸各国为中心多发的淋巴瘤和白血病,据Gallo和日沼等证实病原病毒是逆转录病毒的人I型T淋巴细胞病毒(HTLV—I)。吉田等确定了病毒基因的全部碱基序列。 HTLV—I的主要传播途径,是以母乳为媒介的母子间垂直传播、经性行为的横向传播及输血,但详细的传播机制还不完全清楚。HTLV—I如进入人的淋巴细胞内,就与其他逆转录病毒一样,两条病毒RNA经自身的逆转录酶作用转化为DNA,形成双链DNA后随机插入宿主DNA中,以前病毒DNA的形式继续存在。因此,可用HTLV—IDNA诊断ATL患者的淋巴细胞DNA。 相似文献
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NKT细胞是一群介于NK细胞和T细胞间的细胞,它们同时表达多种NK细胞和T细胞的一些表面标志分子。在生物体的多种免疫反应中,如抗微生物感染,自身免疫病的发生,移植物的存活和抗肿瘤的发生和转移,均发挥重要作用。 相似文献
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T4病毒科由一类单股正链RNA病毒组成,分为松天蛾β样病毒属和松天蛾ω样病毒属。这2个属的病毒具有不同的基因组结构,β样病毒含单组分基因组,其结构蛋白由一亚基因组RNA表达; 而ω样病毒含双组分基因组,2个RNA分子分别编码复制酶蛋白和结构蛋白。在T4病毒基因组RNA 3′端有类似tRNA的二级结构。ω样病毒壳蛋白的氨基酸序列一致性高达66%~86%, 而β样病毒壳蛋白的氨基酸同源性则要低得多。在昆虫细胞中表达壳蛋白基因时都能形成病毒类似粒子。该文还介绍了T4病毒复制机理以及T4病毒与其他病毒的进化关系。 相似文献
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作为肿瘤微环境的重要组成部分, T淋巴细胞在肿瘤的发生、发展中发挥着极其重要的作用,被称为人体内的特种兵。但由于免疫逃逸机制的存在,癌细胞通常会伪装自己,让T细胞无法被识别出,以此躲避人体免疫系统的攻击,那么到底要如何唤醒体内的T细胞来歼灭癌细胞,成为当下肿瘤研究的热点。在过去的几十年,从基础研究到临床应用,诞生了多种基于T淋巴细胞免疫反应的新型抗肿瘤治疗方法,主要有以下三种类型:细胞毒性T淋巴细胞治疗、嵌合抗原受体T细胞治疗以及T细胞受体工程化T细胞治疗。该文简要综述了这三种T细胞免疫治疗的机制、技术与临床应用。 相似文献
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CHRISBLEACKLEY 《Cell research》2002,(Z1)
Cytotoxic T lymphocytes and natural killer cells protect us against a variety of pathogens, and are involved in autoimmune diseases and transplant rejection. Granzyme B plays a major role in the mechanism used by these cytolytic effectors to destroy the target cells. This proteinase is produced by the effectors and stored within cytoplasmic granules. Upon interaction with the pathogenic cell the granzyme is transferred from the CTL to the target via directed exocytosis and subsequent receptor mediated endocytosis. It is interesting that cells that are deficient in expression of the receptor for granzyme are also resistant to CTL- 相似文献
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《Endocrine practice》2012,18(5):750-757
ObjectiveTo evaluate the existing evidence regarding the combined use of levothyroxine and liothyronine to treat hypothyroidism.MethodsEleven published randomized controlled trials evaluating the efficacy and safety of combined levo- thyroxine and liothyronine therapy for hypothyroidism were reviewed and summarized. Related basic and clinical research findings were also incorporated for perspective.ResultsAn initial randomized controlled trial reported symptomatic improvement in hypothyroid patients taking combined levothyroxine and liothyronine therapy compared with those taking levothyroxine therapy alone. Subsequently, multiple relatively small randomized controlled trials failed to demonstrate any subjective or objective benefit from combined levothyroxine and liothy- ronine therapy. A polymorphism (Thr92Ala) in the gene encoding the deiodinase 2 (D2) enzyme that converts thy- roxine to triiodothyronine in the brain was later identified in about 16% of hypothyroid persons. This polymorphism may impair brain deiodinase activity in the presence of low brain thyroxine levels. One randomized controlled trial found that patients with the D2 Thr92Ala polymorphism had more baseline symptoms than those with the wild type D2 and experienced significantly greater symptomatic improvement in response to combined levothyroxine and liothyronine therapy.ConclusionsMost hypothyroid patients experience rapid symptomatic relief after institution of levothyroxine replacement therapy, but persistent symptoms remain in some despite what appears to be adequate levothyroxine therapy with normalization of the serum thyrotropin level. A thorough investigation is warranted in these patients to detect and treat other responsible lifestyle issues, medical conditions, and endocrine conditions. A subset of hypo- thyroid patients has a polymorphism in the gene encoding the D2 enzyme that may prevent full resolution of symp- toms with levothyroxine therapy alone; these patients may benefit from combination levothyroxine and liothyronine therapy. (Endocr Pract. 2012;18:750-757) 相似文献
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Koyasu S 《Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme》2000,45(11):1795-1800
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《生命科学》2017,(11)
T细胞受体(T cell receptor,TCR)基因转导的T细胞疗法(TCR-T)是目前发展较快的一种新的过继性细胞免疫疗法,该方法主要是将肿瘤特异的TCR基因通过各种载体转入自体或异体的淋巴细胞中,再回输至患者体内以达到杀伤肿瘤细胞的目的。因此,肿瘤特异的高亲和性的TCR基因的获取是提高TCR-T细胞治疗的一个重要因素,TCR基因的高水平表达和TCR双链的正确配对也是确保TCR能够在T细胞表面发挥正常抗原识别功能的必要条件。现对TCR的表达及调控机制、TCR基因转导和亲和力的优化策略,以及TCR-T在肿瘤治疗临床试验中的进展与所面临的问题做了详细的阐述。 相似文献
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用^1H NMR法测定T18肽在DMSO(MS18)和50%六氟异丙醇(FP18)中的溶液构象。MS18含有Ile3 ̄Glu7和Ala12 ̄Gln16两段β-折叠链;而FP18则转变为α-螺旋结构。综合分析T14,T18和TDK三个模型肽的结构性质和稳定性,比较肽链序列和溶剂作用,提出肽链局部优势结构的概念,并据此讨论天花粉蛋白小结构域折叠起始过程。 相似文献
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陈军浩张葵 《现代生物医学进展》2012,12(2):389-392
CD4+CD25+FOXP3+的调节T细胞(regulatory T cells,Treg)在维持机体免疫平衡方面起着重要的作用。体外扩增Treg细胞用于治疗自身免疫病、哮喘及诱导器官移植免疫耐受引起人们极大的兴趣。Treg细胞可分为2个亚群,分别为nTreg和iTreg,两者有不同的生物学特性。nTreg在特定条件下,可以分泌具有促进炎症的IL-17;iTreg在体内可丢失FOXP3,失去其免疫抑制功能。Treg细胞用于临床治疗,还有许多问题需要研究解决。 相似文献