ALLOGENEIC MIHA INDUCED MARROW ALLOGRAFT RESISTANCE

即使在HLA匹配的同种异体BMT后，对造血祖细胞同种异体移植的抵抗也是有问题的。使用T细胞耗尽的接种物和不断努力减少化疗/放疗准备方案，以减少BMT后的免疫抑制，将增加需要更好地了解植入的“屏障反应”。在拟定的研究中，将使用MHC匹配、次要H抗原（MiHA）不匹配BMT模型研究同种异体BMT后植入抵抗的细胞和效应子途径。为了检查BMT后立即在不同宿主隔室中屏障反应的动力学和强度，将通过CFU功能直接评估祖细胞功能。将通过CFU试验检查代表定型和多潜能群体的干细胞，以确定对不同群体的选择性耐药性。MiHA重组近交系将用作骨髓供体/受体，以检查屏障应答中的免疫显性。研究将挑战的概念，细胞介导的细胞毒性，通过穿孔素和FasL的主要途径是关键的分子途径，在宿主抗性移植到细胞毒性双缺陷（cdd）受体。将来自TNF受体1和/或2敲除供体的祖细胞移植到cdd受体将产生新的“细胞毒性三重缺陷”模型以评估这些信号传导途径的作用。将检查纯化的Lin-Sca-1+多能干细胞群的直接凋亡杀伤。如果检测到细胞凋亡，将通过RT-PCR检查死亡受体的祖细胞RNA表达。如果未检测到干细胞杀伤，将通过前向移植检查功能抑制，以评估“抗性”是否可逆，是否可能由具有可证实的抗造血活性的细胞因子介导。这些研究中受移植受者不同功能缺陷影响的祖细胞类型的差异将为将不同的效应子途径与不同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.