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991.
Structural studies of murine I-E and human DR antigens. 总被引:8,自引:0,他引:8
The structures of murine I-E antigens from two strains of mice were compared to each other and to human DR antigens. Murine and human antigens were isolated by using allo- and xenoantiserum, respectively, and purified by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The murine I-E and human DR antigens consist of two polypeptide chains designated α and β. The Eα and DRα chains display a high degree of amino acid sequence homology as do the Eβ and DRβ chains, provided a gap is inserted at position 1 of the DRβ chain. Comparison of N-terminal sequences reveals several differences between the β chains of I-E antigens from the two strains of mice. In contrast no sequence differences between the two α chains are observed. In addition, comparison of tryptic peptides examined by isoelectrofocusing reveals several differences between the two Eβ chains, but not between the two Eα chains. Thus, the polymorphism of murine I-E antigens and by analogy human DR antigens, may result from structural differences in the smaller (β) chain. 相似文献
992.
W Z Wang T Olsson V Kostulas B Hjeberg H P Ekre H Link 《Clinical and experimental immunology》1992,88(1):157-162
T cell reactivities to the putative autoantigens myelin basic protein (MBP), MBP peptides with amino acid residues 110-128 and 148-165, and myelin proteolipid protein (PLP) were examined in patients with acute ischaemic cerebrovascular disease (CVD) and, for comparison, in patients with inflammatory neurological diseases and other neurological diseases. A quantitative measure of these T cell reactivities was obtained by assessing numbers of T cells among blood and cerebrospinal fluid (CSF) mononuclear cells that secreted IFN-gamma in response to antigen in vitro. Higher numbers of T cells reactive with each of these four antigens were detected in peripheral blood from patients with CVD compared with patients of the two control groups. Among blood cells from the CVD patients, their average number was 2.3-4.2/10(5) mononuclear cells. MBP reactive T cells were several-fold enriched in the CSF of CVD patients. The findings strongly suggest that brain damage in context with acute CVD leads to an in vivo expansion of myelin reactive T cells. 相似文献
993.
B. N. Gupta 《Pflügers Archiv : European journal of physiology》1977,367(3):271-275
Summary In the attempt to explain the difference in discharge pattern of atrial endings, 131 endings were localized by punctate stimulation, 44 were type A, 77 type B and 10 of an intermediate type. All were located on the dorsal wall of the atria with none on the ventral wall or in the appendage. On the right side, 74% of type A were located in the atria and 63% of type B in or near the veins. On the left side, 67% of type A and 94% of type B were located in or near the veins. Thus, there appeared to be some difference in the location of type A and type B endings on the right side, but on the left side both types of endings were for the most part confined to the venous region. Further, on both right and left sides, these endings were present both in the central part of the atria and in or adjacent to veins. This leads to the suggestion that the difference in discharge patterns is not caused by the location but may be due to some other reasons, e. g. difference of arrangement in the atrial wall with respect to the contractile elements. 相似文献
994.
以基因表达谱芯片对Ty2 1a免疫前后小鼠肠细胞 (包括肠粘膜上皮细胞和肠上皮间淋巴细胞 )基因表达的差异性进行研究比较。将 490条经抑制消减杂交法筛选出的与小鼠Ty2 1a免疫相关的cDNA制备成表达谱芯片 ;利用免疫前后小鼠肠细胞的mRNA通过逆转录方法 ,将Cy3和Cy5两种荧光分别标记到两种组织的cDNA上 ,制备成cDNA探针 ,并与表达谱芯片进行杂交及扫描 ,单点重复 2次实验 ,通过计算机数据处理判定基因是否在上述两种细胞群中有表达差异。筛选出差异表达基因共 98条 ,其中 92条为表达上调基因 ,6条为表达降低基因。提示 ,基因表达谱芯片技术是高通量进行基因表达模式研究的方法 ,可同时定量研究大量的基因表达水平 ,从而鉴定可能参与免疫的基因。 相似文献
995.
目的 研究重组质粒表达载体介导的短发夹式RNA(shRNA)对乳腺癌MCF-7细胞株中血管内皮生长因子C(VEGF-C)的表达及乳腺癌细胞增殖、侵袭能力的影响.方法 脂质体介导重组质粒pSIREN-VEGF-C转染乳腺癌MCF-7细胞株,嘌呤酶素筛选阳性克隆;荧光定量PCR及Western blot检测转染前后乳腺癌MCF-7细胞中VEGF-C基因的表达;MTT法及Transwell体外侵袭实验检测转染前后乳腺癌MCF-7细胞的增殖及侵袭能力.结果 转染重组质粒后乳腺癌MCF-7细胞中VEGF-C mRNA及蛋白表达均明显下调,抑制率分别为95%及100%(P<0.05);MTT法和 Transwell体外侵袭实验显示,与阴性质粒组和空白对照组比较,转染重组质粒后各时间段乳腺癌MCF-7细胞增殖均明显受抑制(P<0.05),同时穿膜的肿瘤细胞数也明显减少[(29.0±1.9)个与(59.0±2.1)个和(61.0±2.2)个相比,P<0.05].结论 表达VEGF-C shRNA的重组质粒载体pSIREN-VEGF-C在乳腺癌MCF-7细胞中能高效、特异地发挥靶基因沉默作用,并对乳腺癌细胞的增殖及侵袭能力有显著抑制作用. 相似文献
996.
D Soldateschi S Censini V de Gori G Antoni A Tagliabue D Boraschi 《Immunobiology》1984,166(3):251-262
Mouse peritoneal M phi and human blood monocytes were assayed for their antitumor activity in vitro with a cytolysis, a cytostasis and a cytotoxicity test performed in parallel. Both natural and stimulus-induced M phi antitumor capacities were assessed. Results indicate that natural cytolytic activity of unstimulated M phi is generally unable to restrict final tumor cell growth, since it is not coupled with cytostatic capacity. In contrast, exposure of M phi in vitro to either MAF or IFN-beta, besides augmenting M phi cytolytic capacity, induced a very significant cytostatic activity and thus efficiently restricted the survival of tumor cells. 相似文献
997.
Mounir Fouad F Mamer O Khayyal M Sauriol F Lesimple A Ruhenstroth-Bauer G 《Medical hypotheses》2004,63(6):1024-1034
We are elaborating on the kinetics and mechanisms of septic rabbit liver to de novo biosynthesize acute-phase response (APR) proteins under in vitro conditions of deepening ischemia in reference to their in vivo prevalence in serum and cerebrospinal fluids (CSF) collected at predetermined times. The significance of the data is interpreted as relevant to grafting cadaveric liver into end-stage liver diseased patients and APR-induced ischemic heart diseases (IHD). Hepatic APR was induced by CCl(4)-intubation, and the administration of cholera toxin (CT) or scorpion venom (SV), or both, to rabbits. Hepatic functional efficiency, in terms of biosynthesis of APR proteins in closed circuit perfusion of the isolated intoxicated liver with oxygenated saline or L-15 media paralleled the two-dimensional immunoelectrophoresis (2D-IEP) spectrum of APR serum proteins at time of liver isolation. We are suggesting: (a) in vitro biosynthesis of plasma proteins by isolated perfused liver is the result of in vivo decoded and retained APR inflammatory signals; and (b) decoded inflammatory signals are expressed not withstanding the perfusate's organic composition. Furthermore, 90 min of ischemic perfusion in saline or L-15 medium precipitated mitochondrial aberrations which resulted in further deterioration of de novo biosynthesis of APR plasma proteins. Regardless of the nature of the inflammatory stimuli, mitochondrial aberrations rendered the perfused organ a biologically inert tissue mass that was incapable of resuming biological function upon perfusion with oxygenated L-15 medium. This is most likely due to ischemia-induced irreversible hepatic necrosis. Thus, in vitro aberrations of mitochondrial function(s) critically limit the capability of the isolated liver to resume its organic function to sustain biosynthesis of de novo plasma proteins. Extrapolation of these results to the surgical management of end-stage liver diseases points to the importance of the status and the handling protocol(s) of the cadaver donor liver prior to successful grafting. We conclude that although histology of a cadaver liver may reveal well-preserved hepatic cellular organelles with at least minimal intra- and intercellular communication required for viable hepatic function, we deem it essential to further define acceptable minimal capabilities to de novo biosynthesize plasma proteins by a cadaver liver as a measure of its functional viability and suitability for transplantation. Ultimately, this measure may improve the success of liver transplants with minimal surgical and drug interventions. 相似文献
998.
干细胞是一类具有自我复制和多分化潜能的细胞 ,根据其发育阶段不同 ,分为胚胎干细胞和成体干细胞。胚胎干细胞具有多分化潜能 ;而成体干细胞的分化潜能则较为局限 ,只能定向分化为特化细胞。但新近的研究表明 ,成体干细胞在一定条件下可分化为与其所在组织不同的其他组织类型细胞 ,这种干细胞的可塑性被称为成体干细胞的横向分化(transdifferentiation)。其中造血干细胞 (hematopoieticstemcells,HSC)作为人们认识最深入 ,其临床应用也最为广泛的一类成体干细胞 ,目前已成为成体干细胞可塑性… 相似文献
999.
BACKGROUND: Rat basophilic leukemia (RBL-2H3) cells are well characterized in terms of morphological and biochemical changes upon activation, and have been extensively used as a model system for studying the mechanisms of the immediate hypersensitivity reaction. To investigate whether overexpression of heat shock/stress proteins (HSP) is involved in the mast cell-dependent reactivity, we examined the adaptive responses of RBL-2H3 cells to classical stress conditions such as heat shock or oxidative injury produced by an aqueous extract of tobacco smoke. METHODS: HSP were determined by flow cytometry and immunocytochemistry. Degranulation was confirmed as the release of beta-hexosaminidase, determined spectrophotometrically, and by electron microscopy experiments. RESULTS: We found that RBL-2H3 cells respond to heat shock or oxidative injury by the synthesis of both the inducible 72 kDa HSP (Hsp70), and the oxidation-specific 32 kDa heme oxygenase (HO)-1. Heat shock induced mainly Hsp70 in a cell growth-dependent manner, whereas oxidative stress induced mainly HO-1 in a cell growth-independent manner. However, heat shock or oxidative stress had no significant effects on degranulation. CONCLUSION: Stress-mediated synthesis of HSP was not associated with RBL-2H3 degranulation and likewise, degranulation did not induce HSP. 相似文献
1000.