ANTILEUKEMIC EFFECT OF IRRADIATED ALLOGENEIC LYMPHOCYTES

描述：(申请人摘要)移植物抗宿主病(GVHD) 异基因骨髓移植(BMT)受者可以通过以下方法预防 同种异体移植物的T细胞耗竭(TCD)，但这会导致 移植物排斥反应和白血病复发的频率。申请人有 研究了辐射同种异体白细胞作为一种新方法的应用 支持移植并保存供者淋巴细胞的GVL效应 不会引起移植物抗宿主病。初步工作确定为7.5Gy射线 在保存同种异体T细胞的同时抑制其增殖能力 它们的体外细胞毒性和促进植入的能力 TCD体内同种异体骨髓。同种异体受照组织的TCD研究 脾细胞消除了移植物促进活性。多次注射 照射后的同种异体脾细胞增加了无白血病的比率 同种异体TCD骨髓移植小鼠的存活 白血病细胞与异基因TCD、BMT和白血病受者的比较 独自一人。这些研究的总体假设是，受辐射的供体 白细胞对宿主提供不同的短期同种异体反应性 白血病细胞和促进供者造血植入而不产生 BMT设置中的GVHD。辐射损伤的可能作用机制 同种异体白细胞包括对正常和 白血病宿主造血细胞；细胞因子的产生 对宿主细胞的抗增殖或细胞病变作用；或 增强联合给药的同种异体反应性 抗辐射的供体细胞。为了研究这些机制，提出了 三个具体目标。在第一个具体目标中，申请者将确定 负责移植物促进和GVL活性的细胞 照射后的同种异体淋巴细胞。他将使用浓缩的或 缺乏T或NK细胞和突变的SCID和褐鼠 T细胞和NK细胞，以确定这些细胞是否介导了 移植物促进和GVL效应。辐照后的抗白血病活性研究 同种异体脾细胞将通过联合移植的受者进行测试 转MRP-8/bcl-2/lpr基因的同源髓系白血病小鼠 自发性地发展成髓系白血病。在第二个具体目标中， 申请者将确定抗白血病的分子机制 照射后白细胞活性检测细胞贡献率 接触性细胞溶解与细胞病变或细胞抑素的释放 辐照细胞产生的可溶性因子。在第三个具体目标中， 申请人将测试是否通过以下方式启动同种异体脾细胞捐赠者 异体免疫或联合细胞因子可增强移植物促进和移植物抗宿主病 照射后淋巴细胞的活性。多次注射辐照后的 白细胞将被用于建立初始植入；随后 输注未照射的供者白细胞将用于根除 当发生急性移植物抗宿主病的风险降低时，残留宿主类型的细胞。

DESCRIPTION: (Applicant's Abstract) Graft-versus-host disease (GVHD) in allogeneic bone marrow transplantation (BMT) recipients can be prevented by T-cell depletion (TcD) of the allograft, but this results in increased frequencies of graft rejection and leukemia relapse. The applicant has investigated the use of irradiated allogeneic leukocytes as a novel method to support engraftment and preserve the GVL effect of donor lymphocytes without causing GVHD. Preliminary work established at 7.5 Gy radiation inhibits the proliferative potential of allogeneic T-cells while preserving their in vitro cytotoxicity and their capacity to facilitate engraftment by TcD allogeneic bone marrow in vivo. TcD of irradiated allogeneic splenocytes eliminated the graft facilitating activity. Multiple injection of irradiated allogeneic splenocytes increased the rate of leukemia-free survival in mice transplanted with allogeneic TcD bone marrow and congenic leukemia cells compared to recipients of allogeneic TcD BMT and leukemia alone. The overall hypothesis of these studies is that irradiated donor leukocytes provide differential short-term allo-reactivity against host leukemia cells and promote donor hematopoietic engraftment without producing GVHD in the BMT setting. Possible mechanisms of action of irradiated allogeneic leukocytes include enhanced cytolytic activity against normal and leukemic host hematopoietic cells; production of cytokines that mediate an anti-proliferative or cytopathic effect against host-type cells; or enhancement of the allo-reactivity of co-administered non-irradiated or radio-resistant donor cells. To investigate these mechanisms are proposed three specific aims. In the first specific aim, the applicant will identify the cells responsible for the graft-facilitating and GVL activity of irradiated allogeneic lymphocytes. He will use splenocytes enriched or depleted for T or NK-cell populations and mutant SCID and beige mice lacking T and NK cells respectively to determine whether these cells mediate the graft-facilitating and GVL effect. The anti-leukemia activity of irradiated allogeneic splenocytes will be tested using recipients co-transplanted with a congenic myeloid leukemia line or mrp-8/bcl-2/lpr transgenic mice that spontaneously develop myeloid leukemia. In the second specific aim, the applicant will determine the molecular mechanisms of the anti-leukemia activity of irradiated leukocytes testing the contribution of cell contact-dependent cytolysis vs. the release of cytopathic or cytostatic soluble factors by irradiated cells. In the third specific aim, the applicant will test whether priming donors of allogeneic splenocytes by allo-immunization or with cytokines enhances the graft facilitating and GVL activity of irradiated lymphocytes. Multiple injections of irradiated leukocytes will be used to establish initial engraftment; subsequent infusion of non-irradiated donor leukocytes will be used to eradicate residual host-type cells when the risk for developing acute GVHD is reduced.