MEMORY AND REGULATORY T CELLS FOLLOWING T CELL DEPLETION IN TRANSPLANTATION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 淋巴细胞耗尽会显著降低T细胞的总数，以试图抑制对同种异体移植的排斥反应。不幸的是，这些耗尽剂通过记忆T细胞的保留、稳态增殖和记忆主导的恢复过程中的免疫激活来促进T效应器/记忆细胞的再繁殖。在这项研究中，我们定义了这些因素在淋巴细胞减少症诱导的记忆T细胞扩增中所起的作用，并进一步描述了短期他克莫司或西罗莫司治疗延缓排斥反应的能力。 根据MHC-I类分型、CFSE混合淋巴细胞反应和FN18阳性，选择猕猴配对。肾移植后，动物接受CD3免疫毒素(0.025 mg/kg/剂量，2次/d)治疗，或联合他克莫司或西罗莫司治疗。用流式细胞仪检测全血细胞计数和T细胞表型。 与未经处理的对照组相比，CD3-IT处理的动物移植物存活率显著增加(6.5天比12天)。T细胞明显耗尽，在第4天达到最大值(99.30.1%耗竭)。然而，与化学偶联的(CRM9-FN18)CD3-IT不同的是，这种新的重组CD3-IT(A-dmDT390-scfbDb)在一周内显示出快速的T细胞再繁殖(92.91.6%)，并按比例转化为CD28lowCD95intCD8T细胞和CD28hiCD95hiCD4T细胞。具有效应记忆的CD8 T细胞(61.2 5.7 vs.40.8 6.2；p0.05)和具有中心记忆表型的CD4T细胞(61.9 10.1 vs.14.0 4.8；p0.05)的数量持续高于治疗前。 此外，我们观察到在1wk时，淋巴结中T细胞的不完全耗竭(73.9±17.7%；n=2)与外周血中T细胞的不完全耗竭(93.8±0.9%；n=5)相比。他克莫司和西罗莫司的维持都延缓了T细胞记忆表型改变的步伐，但并不能最终防止急性排斥反应。有必要进一步研究以提高rCD3-IT在预防急性细胞排斥反应中的潜在作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Lymphocyte depletion acutely lowers the overall number of T cells in an attempt to dampen rejection to allograft. Unfortunately, these same depleting agents promote T effector/memory cell repopulation through a combination of memory T cell sparing, homeostatic proliferation, and immune activation on memory-dominated recovery. In this study, we defined the role these factors play in lymphopenia-induced memory T cell expansion, and further describe the ability of short-term tacrolimus or sirolimus treatment to delay rejection. Rhesus macaques were selected as pairs based on MHC Class I typing, CFSE-based mixed lymphocyte response and their FN18 positivity. Following renal transplantation with native nephrectomy, animals were treated with either CD3-Immunotoxin alone (0.025mg/kg/dose, BID for 4 days), or treated in combination with tacrolimus or sirolimus. Complete blood count and T cell phenotype was monitored by flow cytometrical analysis. Compared to untreated controls, CD3-IT treated animals showed significantly increased graft survival (6.5 vs. 12 days). Significant T cell depletion was observed, and was maximal at day 4 (99.3 0.1% depletion). However, unlike chemically conjugated (CRM9-FN18) CD3-IT, this new recombinant CD3-IT (A-dmDT390-scfbDb) showed rapid repopulation of T cells (92.9 1.6% depletion) within a week, with proportional phenotypic transformation into CD28lowCD95intCD8 T cells and CD28hiCD95hiCD4 T cells. CD8 T cells with effector memory (61.2 5.7 vs. 40.8 6.2; p0.05) and CD4 T cell with central memory phenotype (61.9 10.1 vs. 14.0 4.8; p0.05) reached numbers that were consistently higher than pre-treatment. Furthermore, we observed incomplete depletion (73.9 17.7%; n=2) of T cells in lymph nodes compared to the peripheral blood (93.8 0.9%; n=5) at 1 wk. Both tacrolimus and sirolimus maintenance delayed the pace of T cell memory phenotypic changes, but did not ultimately prevent acute rejection. Further studies are necessary to improve the potential role of rCD3-IT to prevent acute cellular rejection.