ALLOGENEIC MIHA INDUCED MARROW ALLOGRAFT RESISTANCE

即使在人类白细胞抗原相合的异基因骨髓移植后，对造血祖细胞同种异体移植的抵抗也是有问题的。使用耗尽T细胞的疫苗，以及继续努力减少化疗/放射准备方案以减少骨髓移植后的免疫抑制，将增加更好地了解植入的“屏障反应”的必要性。在拟议的研究中，将使用MHC匹配、微小H抗原(MIHA)不匹配的骨髓移植模型来研究异基因骨髓移植后潜在的植入抵抗的细胞和效应途径。为了检测骨髓移植后不同宿主间屏障反应的动力学和强度，将直接用CFU功能来评估祖细胞功能。代表承诺和多个潜在群体的干细胞将通过CFU分析进行检查，以解决对不同群体的选择性耐药性。MIHA重组近交系菌株将被用作骨髓供体/受体，以检测屏障反应中的免疫优势。研究将挑战通过穿孔素和FasL的主要途径介导的细胞毒性是细胞毒双缺陷(CDD)受体在宿主抵抗过程中使用的关键分子途径的观点。将来自肿瘤坏死因子受体1和/或2基因敲除供体的祖细胞移植到CDD受者体内，将建立一个新的细胞毒性三缺失模型来评估这些信号通路的作用。将检测对纯化的LIN-SCA-1+多潜能干细胞群体的直接凋亡杀伤作用。如果检测到细胞凋亡，将用RT-PCR检测死亡受体的前体细胞RNA的表达，如果没有检测到干细胞杀伤，将通过向前移植检查功能抑制，以评估这种耐药是否可逆，并可能是由具有明显抗造血活性的细胞因子介导的。由于移植受者不同的功能缺陷而影响的祖细胞类型的不同，这些研究将为将不同的效应通路与不同的造血祖细胞群体的靶向联系起来提供新的见解。

Resistance to hematopoietic progenitor cell allografts is problematic, even after HLA-matched allogeneic BMT. The use of T cell depleted inoculum and the continuing efforts to diminish chemo / radiation preparative regimens to reduce post-BMT immunosuppression will increase the need to better understand the `barrier response' to engraftment. In the proposed studies, the cellular and effector pathways underlying resistance to engraftment following allogeneic BMT will be investigated using a model of MHC matched, minor H antigen (MiHA) mismatched BMT. To examine the kinetics and strength of the barrier response in differing host compartments immediately post-BMT, progenitor function will be directly assessed by CFU function. Stem cells representative of committed and multi potential populations will be examined by CFU assay to address for selective resistance against differing populations. MiHA recombinant inbred strains will be used as marrow donors /recipients to examine immunodominance in barrier responses. Studies will challenge the notion that cell-mediated cytotoxicity via the major pathways of perforin and FasL are the crucial molecular pathways used during host resistance by transplants into cytotoxic double deficient (cdd) recipients. Progenitor cells from TNF receptor 1 and/or 2 knock out donors transplanted to cdd recipients will create a novel `cytotoxic triple deficient' model to assess the role of these signaling pathways. Direct apoptotic killing of purified Lin-Sca-1+ pluripotential stem cell populations will be examined. If apoptosis is detected, expression of progenitor cell RNA for death receptors will be examined by RT-PCR If stem cell killing is not detected, functional inhibition will be examined by forward transplant to assess if the `resistance' is reversible and may be mediated by cytokines with demonstrable anti-hematopoietic activity. Differences from these studies in the types of progenitor cells affected as a consequence of differing functional deficits in transplant recipients would provide novel insights towards linking distinct effector pathways to the targeting of differing hematopoietic progenitor populations.