TRANSPLANT IMMUNOMODULATION BY ALLOCHIMERIC MOLECULES

描述（由申请人提供）： 我们寻求开发一种临床上可应用的策略，以诱导用同种异体嵌合I类MHC分子治疗的“真正”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提供了基础。我们假设：（i）同种异体嵌合诱导的耐受适用于遗传多样的同种异体移植受体;（ii）同种异体嵌合分子通过间接呈递调节免疫应答;（iii）同种异体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.确定诱导耐受的不同全嵌合体分子的要求。将构建不同菌株组合中的多个同种异体嵌合分子，以确定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全嵌合分子诱导“真正的”慢性无排斥耐受的能力。2.通过间接呈递异源嵌合[alpha 1h I/u]-RT1.Aa I类MHC分子分析全免疫调节将进行对同种异体移植耐受性至关重要的免疫原性/隐蔽自身表位的精细定位。T细胞应答的间接异源嵌合偏离将通过使用已在体外用供体野生型或α 1 h 1/u]-RT1.Aa分子脉冲的宿主或供体型树突状细胞来解决。异源嵌合体蛋白的标记和检测将定位异源嵌合体加工和呈递中涉及的位点和细胞类型。将通过使用FIT 3L（一种造血生长因子）功能性刺激DC成熟和同种异体刺激能力，在体内研究用于同种异体嵌合耐受诱导的“不成熟与成熟”肝DC的需求，以潜在地消除门静脉内同种异体嵌合递送后间接诱导的耐受。3.间接同种异体识别诱导的独特调节性T细胞群的特征。我们将进行调节性T细胞的体内和体外表型和功能表征。调节性T细胞的异源嵌合生成，在这个模型中可能是一个关键的致耐受性机制，将在体外探索通过研究未成熟的肝树突状细胞，间接提出异源嵌合分子的CD 4 + T细胞。第三，慢性排斥反应的体内分析结合同种异体嵌合诱导的克隆限制性调节性T细胞的CDR 3谱分型、免疫显微镜和序列分析将定义独特的T细胞功能特异性和同种异体嵌合序列对同种异体特异性TcR库的影响。

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.