CD8 in the Immunological Synapse and in Thymocyte Death

CD8 在免疫突触和胸腺细胞死亡中的作用

• 批准号: 6780797
• 负责人: TERRY A POTTER
• 金额: $ 34.11万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6780797
• 关键词: MHC class I antigen; SDS polyacrylamide gel electrophoresis; T cell receptor; antigen presentation; antigen presenting cell; apoptosis; biological signal transduction; cell cell interaction; crosslink; cytotoxic T lymphocyte; genetically modified animals; glycosylation; helper T lymphocyte; laboratory mouse; ligands; phosphorylation; polymerase chain reaction

DESCRIPTION (provided by applicant): During the interaction of T cells with antigen presenting cells (APCs), receptors and intracellular proteins translocate into the contact region known as the Immunological Synapse (IS). In CD4 T cells IS formation can readily be rendered independent of CD4 by increasing the amount of antigenic peptide whereas the same does not hold true for CD8 T cells. In addition, CD4 rapidly moves out of the center of the IS whereas we do not observe any such clearance of CD8. In this proposal we shall examine the IS of CD8 T cells interacting with APCs. In particular we shall focus on the requirement of the CD4/8 co-receptor and on the movement of both antigenic and non-antigenic MHC class I molecules. We shall also examine SMAC formation in immature thymocytes during a CD8 mediated, TCR independent interaction with APCs. It has been demonstrated that MHC I tetramers can bind to CD8 on DP thymocytes in a TCR independent manner. This binding event has been attributed to a developmentally regulated difference in the glycosylation of CD8 on DP thymocytes compared to CD8 single positive thymocytes and peripheral T cells. In contrast there is no evidence for TCR independent binding of MHC class II tetramers to CD4 on DP thymocytes. The implications and/or biological relevance of this event have not been determined. Recently we have found that antibody mediated cross-linking of CDS, but not CD4, results in rapid apoptosis of CD4 CD8 (DP) thymocytes. Treatment with the phorbol ester, PMA, prevents the induction of apoptosis resulting from CD8 cross-linking. We hypothesize that the ligation of CD8 by physiological ligands in the absence of TCR engagement leads to the death of DP thymocytes during T cell development. In this application we shall further characterize the induction of apoptosis in DP thymocytes by CD8 antibodies and also investigate whether classical or non-classical MHC class I molecules can induce apoptosis in DP thymocytes in a TCR independent manner. These studies will incorporate 4 specific aims: (1) To determine whether CD8 behaves as a co-receptor within the immunological synapse, for the activation of peripheral T cells (2) To determine the biochemical events leading to the CD8 mediated death of DP thymocytes; (3) To determine the mechanism by which treatment with PMA prevents CD8 mediated death in DP thymocytes; (4) To determine whether CD8 mediated death has a physiological function.

描述（由申请人提供）：在 T 细胞与抗原呈递细胞 (APC) 相互作用的过程中，受体和细胞内蛋白质易位到称为免疫突触 (IS) 的接触区域。在 CD4 T 细胞中，通过增加抗原肽的量，可以很容易地使 IS 形成独立于 CD4，而对于 CD8 T 细胞则不然。此外，CD4 迅速移出 IS 中心，而我们没有观察到 CD8 的任何此类清除。在本提案中，我们将检查 CD8 T 细胞与 APC 相互作用的 IS。我们特别应关注 CD4/8 辅助受体的需求以及抗原性和非抗原性 MHC I 类分子的运动。我们还将检查在 CD8 介导的、不依赖于 TCR 的 APC 相互作用过程中未成熟胸腺细胞中 SMAC 的形成。 已证明MHC I四聚体可以以不依赖于TCR的方式与DP胸腺细胞上的CD8结合。这种结合事件归因于与 CD8 单阳性胸腺细胞和外周 T 细胞相比，DP 胸腺细胞上 CD8 糖基化的发育调节差异。相反，没有证据表明 MHC II 类四聚体与 DP 胸腺细胞上的 CD4 不依赖于 TCR 结合。该事件的影响和/或生物学相关性尚未确定。最近我们发现抗体介导的 CDS 交联（而非 CD4）导致 CD4 CD8 (DP) 胸腺细胞快速凋亡。用佛波酯 (PMA) 处理可防止诱导 CD8 交联引起的细胞凋亡。我们假设在没有 TCR 参与的情况下，生理配体对 CD8 的连接导致 T 细胞发育过程中 DP 胸腺细胞死亡。 在本申请中，我们将进一步表征CD8抗体对DP胸腺细胞凋亡的诱导，并研究经典或非经典MHC I类分子是否可以以不依赖于TCR的方式诱导DP胸腺细胞凋亡。这些研究将包含 4 个具体目标：(1) 确定 CD8 是否作为免疫突触内的辅助受体，激活外周 T 细胞 (2) 确定导致 CD8 介导的 DP 胸腺细胞死亡的生化事件; (3) 确定 PMA 治疗预防 DP 胸腺细胞中 CD8 介导的死亡的机制； (4)确定CD8介导的死亡是否具有生理功能。

项目成果

MPYS is required for IFN response factor 3 activation and type I IFN production in the response of cultured phagocytes to bacterial second messengers cyclic-di-AMP and cyclic-di-GMP.

• DOI: 10.4049/jimmunol.1100088
• 发表时间: 2011-09-01
• 期刊: Journal of immunology (Baltimore, Md. : 1950)
• 作者: Jin L;Hill KK;Filak H;Mogan J;Knowles H;Zhang B;Perraud AL;Cambier JC;Lenz LL
• 通讯作者: Lenz LL