TRANSPLANT IMMUNOMODULATION BY ALLOCHIMERIC MOLECULES

我们试图开发一种临床适用的策略来诱导“真正的”移植耐受，治疗方法是 同种异体嵌合体I类MHC分子。我们在大鼠同种异体心脏移植模型上的新发现为 这项提议。我们假设：(I)异基因嵌合体诱导的耐受适用于遗传多样性的同种异体移植物。 受体；(2)异体嵌合分子通过间接递呈调节免疫反应；(3)异基因嵌合体 分子产生独特的调节性T细胞，具有独特的功能和TCR同种异体特异性。我们建议： 1.明确不同分子诱导耐受的要求。多重同种异体嵌合体 在不同的菌株组合中，将构建分子来定义关键的免疫原性表位 I类MHC的多态区域。在受体上显示供体占优势的表位的化学分子- I类抗原将被测试其诱导“真正的”慢性无排斥耐受的能力。 2.间接递呈同种异体[_LH_U]-RT1.aA-I类MHC分析免疫调节 分子。对同种异体移植耐受至关重要的免疫原性/隐蔽自身表位的精细映射将是 _错误。通过使用宿主或供体类型来解决T细胞反应的间接异基因嵌合偏差 在体外用供体野生型或[OHH_U]-RT1.Aa分子冲击的树突状细胞。无核融合蛋白 标记和检测将定位同种异体处理和呈递过程中涉及的部位和细胞类型。 未成熟与成熟的肝脏DC对同种异体耐受诱导的需求将在体内进行研究 造血生长因子FIt3L对树突状细胞的功能刺激和同种异体刺激能力 潜在地消除门脉内同种异体分娩后间接诱导的耐受性。 3.鉴定间接同种异体识别诱导的独特调节性T细胞群。我们会 进行体内和体外调节性T细胞的表型和功能表征。同种异体嵌合世代 在这个模型中，调节性T细胞的一个可能的关键耐受机制将通过研究在体外进行探索。 未成熟的肝树突状细胞，间接向CD4T细胞递送同种异体分子。第三，活体内 慢性排斥反应结合CDR3基因分型、免疫镜检和序列分析 同种异体融合诱导的克隆性限制性调节性T细胞将定义独特的T细胞功能特异性 同种异体嵌合序列对同种异体TCR谱系和GT的影响

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 b y indirect presentation; (iii) a Ilochimeric 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 [_lh___U]-RT1.aA Class I MHC Molecules. Fine mapping of immunogenic/cryptic self-epitopes that are critical for allograft tolerance will be _erformed. 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 [Ohh_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 matudty and allostimulatory capacity using FIt3L, a heamatopoietic growth factor, to potentially abrogate indirectly induced tolerance following intra-portal allochimeric delivery. 3. To Characterize the Unique Population of Requlatory 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 allochimedc-induced clonally-restricted regulatory T cells will define unique T cell functional specificities and the influence of allochimeric sequence on the allospecific TcR repertoire>