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的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 淋巴细胞耗竭会急剧降低T细胞的总数，试图抑制对同种异体移植物的排斥反应。不幸的是，这些相同的消耗剂通过记忆T细胞保留、稳态增殖和记忆主导恢复的免疫激活的组合促进T效应细胞/记忆细胞再增殖。在这项研究中，我们确定了这些因素在淋巴细胞减少诱导的记忆T细胞扩增中的作用，并进一步描述了短期他克莫司或西罗莫司治疗延迟排斥反应的能力。 基于MHC I类分型、基于CFSE的混合淋巴细胞反应和它们的FN 18阳性选择恒河猴作为配对。在进行自体肾切除术的肾移植后，动物单独用CD3-免疫毒素处理（0.025 mg/kg/剂，BID，持续4天），或与他克莫司或西罗莫司联合处理。全血细胞计数和T细胞表型通过流式细胞仪分析进行监测。 与未处理的对照相比，CD3-IT处理的动物显示出显著增加的移植物存活（6.5天对12天）。观察到显著的T细胞消耗，并且在第4天达到最大（99.3 ± 0.1%消耗）。然而，与化学缀合的（CRM9-FN18）CD3-IT不同，这种新的重组CD3-IT（A-dmDT390-scfbDb）在一周内显示出T细胞的快速再增殖（92.9 ± 1.6%消耗），具有成比例的表型转化为CD28lowCD95intCD8 T细胞和CD28hiCD95hiCD4 T细胞。具有效应记忆的CD8 T细胞（61.2 5.7 vs. 40.8 6.2; p0.05）和具有中枢记忆表型的CD4 T细胞（61.9 10.1 vs. 14.0 4.8; p0.05）达到的数量始终高于给药前。 此外，我们观察到不完全耗尽（73.9 - 17.7%; n = 2）淋巴结中的T细胞相比，外周血（93.8 - 0.9%; n = 5）在1周。他克莫司和西罗莫司维持治疗都延缓了T细胞记忆表型变化的步伐，但最终不能预防急性排斥反应。进一步的研究是必要的，以提高rCD3-IT的潜在作用，以防止急性细胞排斥反应。

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.