TRANSPLANT IMMUNOMODULATION BY ALLOCHIMERIC MOLECULES

通过异种嵌合分子进行移植免疫调节

• 批准号: 6999763
• 负责人: Rafik MARK GHOBRIAL
• 金额: $ 26.06万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6999763
• 关键词: TRANSPLANT; IMMUNOMODULATION; ALLOCHIMERIC; MOLECULES

DESCRIPTION (provided by applicant): We seek to develop a clinically applicable strategy to induce "true" transplantation tolerance treated with allochimeric Class I MHC molecules. Our novel findings in a rat cardiac allograft model provide the foundation of this proposal. We hypothesize: (i) allochimeric-induced tolerance is applicable to genetically diverse allograft recipients; (ii) allochimeric molecules modulate the immune response by indirect presentation; (iii) aIlochimeric molecules generate unique regulatory T cells with distinctive functional and TcR allospecificities. We propose: 1. To Define the Requirements of Different AIIochimeric Molecules to Induce Tolerance. Multiple allochimeric molecules, in different strain combinations, will be constructed to define critical immunogenic epitopes in the polymorphic regions of class I MHC. AIIochimeric molecules that display donor-dominant epitopes on recipient class I antigens will be tested for their ability to induce "true" chronic rejection-free tolerance. 2. To Analyze AIIoimmune Modulation by Indirect Presentation of Allochimeric [alpha1h I/u]-RT1.Aa Class I MHC Molecules. Fine mapping of immunogenic/cryptic self-epitopes that are critical for allograft tolerance will be performed. Indirect allochimeric deviation of T cell responses will be addressed by employing host or donor-type dendritic cells that have been pulsed in vitro with donor wild-type or alpha1h 1/u]-RT1.Aa molecules. AIIochimeric protein labeling and detection will localize the site and cell-type involved in allochimeric processing and presentation. Requirement of 'immature vs mature' hepatic DC for allochimeric tolerance induction will be investigated in vivo by functional stimulation of DC maturity and allostimulatory capacity using FIt3L, a hematopoietic growth factor, to potentially abrogate indirectly induced tolerance following intra-portal allochimeric delivery. 3. To Characterize the Unique Population of Regulatory T Cells Induced by Indirect Allorecognition. We will perform in vivo and ex vivo phenotypic and functional characterization of regulatory T cells. Allochimeric generation of regulatory T cells, a possible key tolerogenic mechanism in this model, will be probed in vitro by studying immature hepatic dendritic cells that indirectly present allochimeric molecules to CD4+ T cells. Third, in vivo analysis of chronic rejection coupled with CDR3 spectrotyping, immunoscope and sequence analysis of allochimeric-induced clonally-restricted regulatory T cells will define unique T cell functional specificities and the influence of allochimeric sequence on the allospecific TcR repertoire.

描述（由申请人提供）： 我们寻求开发一种临床适用的策略，以诱导用异源嵌合 I 类 MHC 分子治疗的“真正的”移植耐受。我们在大鼠心脏同种异体移植模型中的新发现为这一提议奠定了基础。我们假设：（i）同种异体嵌合诱导的耐受性适用于遗传多样性的同种异体移植受者； (ii)异源嵌合分子通过间接呈递调节免疫反应； (iii)异嵌合分子产生具有独特功能和TcR同种异体特异性的独特调节性T细胞。我们建议： 1. 明确不同嵌合分子诱导耐受性的要求。将构建不同菌株组合中的多个同种异源嵌合分子，以定义 I 类 MHC 多态性区域中的关键免疫原性表位。将测试在受体I类抗原上展示供体显性表位的所有嵌合分子诱导“真正的”慢性无排斥耐受的能力。 2.通过间接呈现同种异源嵌合[α1h I/u]-RT1.Aa I类MHC分子来分析所有免疫调节。将进行对同种异体移植物耐受性至关重要的免疫原性/隐性自身表位的精细定位。 T细胞反应的间接同种异体偏差将通过使用已在体外用供体野生型或α1h 1/u]-RT1.Aa分子脉冲的宿主或供体型树突细胞来解决。异源嵌合蛋白标记和检测将定位参与异源嵌合加工和呈递的位点和细胞类型。将通过使用 FIt3L（一种造血生长因子）对 DC 成熟和同种刺激能力进行功能性刺激，在体内研究“未成熟与成熟”肝 DC 对同种异体耐受诱导的要求，以潜在地消除门静脉内异种嵌合递送后间接诱导的耐受。 3. 表征间接同种异体识别诱导的调节性 T 细胞的独特群体。我们将对调节性 T 细胞进行体内和离体表型和功能表征。调节性 T 细胞的同种异体嵌合生成是该模型中可能的关键耐受机制，将通过研究间接向 CD4+ T 细胞呈递同种异体嵌合分子的未成熟肝树突细胞进行体外探索。第三，对慢性排斥反应的体内分析，结合CDR3分型、免疫镜和同种异体诱导的克隆限制性调节T细胞的序列分析，将确定独特的T细胞功能特异性以及同种异体嵌合序列对同种异体特异性TcR库的影响。