TRANSPLANT IMMUNOMODULATION BY ALLOCHIMERIC MOLECULES

我们寻求开发一种临床适用的策略，在同种异体嵌合I类MHC分子治疗的同种异体移植受体中诱导“真正的”移植耐受。我们在大鼠同种异体心脏移植模型中的初步发现为这一建议提供了基础。我们假设：(i)同种异体嵌合诱导的耐受性，作为受体MHC i类分子间接呈递供体型免疫原性表位的功能，适用于遗传多样性的移植物受体；（ii）异体嵌合MHC I类分子的间接呈递诱导产生一种独特的调节性T细胞群，维持和转移一种慢性无排斥的“真正”耐受状态。我们提出以下具体目标：确定不同aio嵌合分子诱导耐受性的条件。假设：表现出供体型免疫原性表位的受体型同种异体嵌合I类分子诱导了对供体型同种异体移植物的“真正”耐受。利用PCR基因SOEing构建不同菌株组合的多个同种异体嵌合分子，以确定I类MHC多态性区域的关键免疫原性表位。在受体I类抗原上显示供体显性表位的嵌合分子将被测试是否有能力诱导“真正的”慢性无排斥耐受性。2. 间接呈递aii嵌合物[c%_JU]-RT1分析aii免疫调节作用。a类MHC分子。假设：aiio嵌合疗法通过间接途径偏离宿主对同种异体器官移植物的免疫反应。对同种异体移植物存活至关重要的免疫原性/隐性自身表位的精细定位将被执行。通过使用宿主或供体型树突状细胞，在体外用供体野生型或[cqh_/U]-RTl进行脉冲处理，可以解决nafv或引物T细胞反应的间接同种异体嵌合偏差。A A分子。通过研究未成熟的肝树突状细胞间接向CD4+ T细胞呈递同种嵌合分子，我们将在体外探索调节性T细胞的嵌合生成，这可能是该模型中关键的耐受性机制。通过使用造血生长因子FIt3L来消除门静脉内同种异体嵌合输注后间接诱导的耐受，研究了在体内刺激肝脏树突状细胞的同种异体刺激能力/成熟度。3. 表征间接抗氧化诱导的调节性T细胞的独特群体。假设：由间接异体识别诱导的调节性T细胞协调耐受的获得和慢性排斥的消除。我们将在体内和体外进行调节性T细胞的表型和功能表征。它们介导CD8+细胞毒性T细胞抑制或直接抑制树突状细胞抗原呈递的能力将在体外进行分析。与细胞因子补充和/或抑制并行的Transwell实验将分析细胞-细胞接触的需求与特定细胞因子的需求。通过分析(i)偏离宿主抗供体同种抗体反应诱导的血管“调节”，（ii）细胞保护分子的上调，以及（iii）移植物浸润单核细胞的功能状态，将研究独特的调节性T细胞对慢性排斥的抑制。>网站性能 ======================================== 节结束 ===========================================

EXCEED THE SPACE PROVIDED We seek to develop a clinically applicable strategy to induce a "true" transplantation tolerance in allograft recipients treated with allochimeric Class I MHC molecules. Our preliminary findings in a rat cardiac allograft model provide the foundation of this proposal. We hypothesize that: (i) allochimeric-induced tolerance, as a function of indirect presentation of donor-type immunogenic epitopes displayed by recipient MHC Class I molecules, is applicable to genetically diverse graft recipients; (ii) indirect presentation of allochimeric MHC Class I molecules induces generation of a unique population of regulatory T cells that maintain and transfer a state of chronic rejection-free "true" tolerance. We propose the following specific aims: 1. To Define the Requirements of Different AIIochimeric Molecules to Induce Tolerance. Hypothesis: Recipient-type allochimeric class I molecules that exhibit donor-type immunogenic epitopes induce '_true" tolerance to donor-type allografts. Multiple allochimeric molecules, in different strain combinations, will be constructed by PCR gene SOEing, 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 the ability to induce a "true" chronic rejection-free tolerance. 2. To Analyze AIIoimmune Modulation by Indirect Presentation of AIIochimeric [c%_JU]-RT1.Aa Class I MHC Molecules. Hypothesis: AIIochimeric therapy deviates host immune responses to organ allografts via indirect pathway. Fine mapping of immunogenic/cryptic self-epitopes that are critical for allograft survival will be performed. Indirect allochimeric deviation of nafve or primed 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 [cqh_/U]-RTl.A a molecules. AIIochimeric 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. In vivo stimulation of hepatic dendritic cell allostimulatory capacity/maturity will be investigated by using FIt3L, a heamatopoietic growth factor, to abrogate indirectly induced tolerance after intra-portal allochimeric infusion. 3. To Characterize the Unique Population of Regulatory T Cells Induced by Indirect AIIorecoflnition. Hypothesis: Regulatory T cells that are induced by indirect allorecognition orchestrate the acquisition of tolerance and abrogation of chronic rejection. We will perform in vivo and ex vivo phenotypic and functional characterization of regulatory T cells. Their ability to mediate CD8+ cytotoxic T cells inhibition or directly suppress antigen presentation by dendritic cells will be analyzed in vitro. Transwell experiments in parallel with cytokine supplementation and/or inhibition, will analyze the requirement of cell-cell contact vs. specific cytokine requirement. The unique regulatory T cell orchestrated inhibition of chronic rejection will be investigated by analyzing (i) vascular "accommodation" induced by deviated host anti-donor alloantibody responses, (ii) upregulation of cytoprotective molecules, and (iii) functional status of graft-infiltrating mononuclear cells. > PERFORMANCE SITE ========================================Section End===========================================