小鼠DC上HVEM与BTLA相互作用对T细胞免疫应答的影响

发布时间：2018-03-17 14:15

本文选题：树突状细胞　切入点：HVEM　出处：《苏州大学》2009年硕士论文　论文类型：学位论文

【摘要】： 启动T细胞免疫应答需要双信号的参与:T细胞抗原受体TCR和抗原递呈细胞(antigen presenting cell, APC)上MHC/抗原肽复合物结合产生的第一信号;T细胞与APC表面的共刺激分子相互作用产生的第二信号。树突状细胞(DC)是已知体内最强的APC,在肿瘤免疫、抗感染免疫、自身免疫和移植免疫中发挥着巨大作用。共刺激分子主要分为两类:肿瘤坏死因子受体超家族(TNFRSF)和免疫球蛋白超家族(IgSF)。HVEM(herpes virus-entry mediator)是TNFRSF成员,BTLA属于IgSF。过去一直认为,所有的IgSF成员只与B7分子家族成员相互作用;而TNFRSF成员只与TNF家族成员相互作用。而BTLA与HVEM的结合改变了传统的看法。这两个分子的结合将两大家族直接联系了起来,也是目前唯一的一对。近年来的研究表明,HVEM既可作为受体与LIGHT作用传递正性协同刺激信号,又能作为配体作用于BTLA介导负性协同抑制信号。HVEM可与BTLA结合并诱导其酪氨酸磷酸化,发挥抑制功能,降低T细胞的增殖能力,BTLA缺陷的T细胞增殖能力增强。HVEM与BTLA结合,发挥负性调节作用,HVEM-BTLA代表了一对新的负性协同刺激分子。本文第一部分采用小鼠骨髓来源的DC(BMDC),就影响HVEM分子在DC表达的因素作些探讨研究。将促DC成熟活化因子LPS、TNF-α、4-1BB分子激发型抗体(2A)、CD40激发型抗体(1c10)和免疫负性调节因子IL-10加入到各组BMDC中,观察BMDC上HVEM表达的变化。结果显示,加入促成熟活化因子的各组BMDC上HVEM表达与对照组相比有显著下调(P0.05),而加入免疫负性调节因子的BMDC上HVEM表达与对照组相比有显著上调(P0.05),提示LPS、TNF-α、2A抗体、1c10抗体可能通过下调DC上HVEM分子的表达,从而在与T细胞相互作用时降低T细胞活化的阈值。反之,IL-10抑制DC免疫功能的另一个可能机制,即上调DC上HVEM分子的表达,抬高T细胞活化的阈值,减弱T细胞的免疫应答。本文第二部分研究C57BL/6 BMDC上HVEM被抗HVEM抗体封闭后,作用于BALB/c小鼠脾脏T细胞,对T细胞活化尤其是早期活化的影响,以及白细胞介素2(IL-2)的分泌情况。检测表明,无论是混合培养的早期(0-48h)还是晚期(48-96h),加抗HVEM抗体封闭的实验组的T细胞增殖效应明显强于对照组。同时IL-2的分泌也高于对照组。说明了HVEM-BTLA传递的信号对T细胞的活化起抑制作用。特别是,在T细胞与DC混合培养早期(0-48h),BTLA即有抑制T细胞活化的作用,这与传统认为T细胞活化后诱导表达负性分子的负反馈调节理论是相矛盾的,提示免疫细胞可能存在多种负性调节方式。综上所述,本研究表明促成熟活化因子LPS、TNF-α、2A抗体、1c10抗体能下调DC上HVEM分子的表达,免疫负性调节因子IL-10能上调DC上HVEM分子的表达。经抗HVEM抗体封闭后的DC刺激T细胞活化的效应增强,与T细胞反应早期(0-48h)和晚期(48-96h)都存在这个现象,尤其在T细胞与DC混合培养早期(0-48h)。BTLA的抑制T细胞活化作用提示免疫细胞除了负反馈调节机制外,可能还存在其它负性调节方式。
[Abstract]:Start the T cell immune response involves two signals: T cell antigen receptor TCR and antigen presenting cells (antigen presenting cell, APC) MHC/ antigen peptide complex with the first signal generated by T and APC; cell surface costimulatory molecules produced by the interaction of the second signal. Dendritic cells (DC) are known the most powerful APC in tumor immunity, infection and immunity, play a huge role in autoimmune and transplantation.
Costimulatory molecules are divided into two categories: tumor necrosis factor receptor superfamily (TNFRSF) and immunoglobulin superfamily (IgSF).HVEM (herpes virus-entry mediator) is a member of TNFRSF, BTLA and IgSF. belong to the past has been that all members of IgSF and only members of the B7 family of molecules interaction; while TNFRSF and TNF family members only members interact with each other. And the combination of BTLA and HVEM changed the traditional view. The combination of these two molecules will directly link up the two families, is currently the only one.
Recent studies show that HVEM can be used as receptor and LIGHT functions to transfer positive costimulatory signal, and can be used as ligands acting on BTLA mediated negative synergistic inhibitory signal.HVEM can combine with BTLA and its induced tyrosine phosphorylation, play inhibitory function, reduce the proliferation of T cells, T cell proliferation ability of BTLA defects the enhanced.HVEM and BTLA combination, play a negative regulatory role, HVEM-BTLA represents a new pair of negative costimulatory molecules.
The first part of this paper using mouse bone marrow-derived DC (BMDC), factors affecting the expression of HVEM molecules in DC are discussed in this paper. The research will promote DC maturation and activation of factor LPS, TNF- alpha, stimulate antibody 4-1BB molecule (2A), CD40 antibody (1c10) and stimulate the immune negative regulation factor IL-10 into groups in BMDC, expression of HVEM was observed on BMDC. The results showed that adding maturation promoting activating factor BMDC on the expression of HVEM in each group compared with the control group were significantly reduced (P0.05), and adding negative immuno regulatory factor BMDC on the expression of HVEM compared with the control group were significantly increased (P0.05), LPS, TNF- alpha, 2A antibody, 1c10 antibody by down-regulation of HVEM expression on DC, thereby reducing the threshold for activation of T cells in interactions with T cells. On the contrary, another possible mechanism of IL-10 inhibiting DC immune function, namely the upregulation of DC expression of HVEM molecules, elevation of T cell activation The threshold, which weakens the immune response of T cells.
The second part of this paper studies C57BL/6 BMDC HVEM by anti HVEM antibody is closed, in the role of BALB/c in mouse spleen T cells, activation of T cells especially the early activation effect, and interleukin 2 (IL-2) secretion. Test showed that both the early mixed culture (0-48h) or late (48-96h) T cell proliferation, anti HVEM antibody closed in the experimental group was significantly stronger than the control group. At the same time, the secretion of IL-2 is higher than that of the control group. The signal transmission of HVEM-BTLA activation of T cells inhibited. In particular, raising early in T cells and DC mixed culture (0-48h), BTLA inhibition the activation of T cells, the expression of negative thought and traditional molecular induced T cell activation after the negative feedback theory is contradictory, suggesting that immune cells may have many negative ways. Regulation
In summary, this study shows that maturation promoting factor LPS activation, TNF- alpha, 2A antibody, 1c10 antibody can decrease the expression of HVEM molecule on DC, immune negative regulator of IL-10 expression of HVEM upregulated by DC. The enhancement effect of anti HVEM antibody after the closure of DC stimulated the activation of T cells, T cells and early response (0-48h) and late (48-96h) the existence of this phenomenon, especially in the early stage of culture T cells mixed with DC (0-48h) activation suggesting that immune cells in addition to negative feedback mechanism of.BTLA inhibition of T cell, there may be other negative regulation.

【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R392

【参考文献】