NONMYELOABLATIVE GRAFTS IN LITTERMATES

该项目的目的是，首先，开发毒性较小的免疫抑制调节方案，用于犬模型中的同种异体造血干细胞移植（HSCT），可应用于没有hla相同的兄弟姐妹供体的患者，其次，改进现有的主要组织相容性复合物匹配受体的方案。在最后的资助期内，我们描述了一种方案，在DLA-相同匹配的狗窝伴侣中，在HSCT之前使用200 cGy的非骨髓消融剂量的全身照射（TBI），在HSCT之后使用霉酚酸酯（MMF）和环孢素（CSP），我们成功地将其转化为患有恶性和非恶性疾病的人类患者。新移植方法的主要基础是使用MMF/CSP进行移植后免疫抑制，不仅可以更好地控制移植物抗宿主病（GVHD），还可以抑制宿主抗移植物反应。这样，训练项目的强度就可以降低。将新原理与先前发表的观察结果相结合，我们已经表明，在移植前给予药物和抗cd44单克隆抗体（Mab, S5），仅在450cgy TBI后，DLA-单倍体相同的HSCT几乎可以均匀建立。我们计划通过评估三种截然不同的方法，将TBI剂量降低到200 cGy的亚致死范围，并在该模型中获得更好的GVHD控制：(1)将移植后MMF/CSP分别从先前使用的28天和35天延长到100天；(2)评估移植周LFA1（白细胞功能抗原-1）拮抗剂；(3)在CD154 （CD40配体）方案中加入CTLA4lg+/-和Mab对T细胞共刺激阻断。在dla相同的幼崽中，我们将研究通过适当的单克隆抗体递送的短寿命α发射放射性核素铋213 （Bi-213）的靶向照射是否可以取代200 cGy的外束TBI，以提供植入所需的免疫抑制。我们将首先用泛造血抗cd45抗体靶向宿主细胞，然后用抗T细胞受体抗体测试T细胞特异性消融。成功的策略将与用毒性较小的免疫抑制方案完全取代TBI的目标结合使用。

The objectives of this project are, first, to develop less toxic immunosuppressive conditioning programs for allogeneic hematopoietic stem cell transplants (HSCT) in a canine model that can be applied to patients who do not have HLA-identical sibling donors and, second, to refine existing regimens for major histocompatibility complex matched recipients. In the last grant period, we described a regimen in DLA- identical matched canine littermates consisting of a non-marrow ablative dose of 200 cGy total body irradiation (TBI) before, and mycophenolate mofetil (MMF) and cyclosporine (CSP) after HSCT, which we successfully translated to human patients with malignant and non- malignant diseases. The principal underlying the new transplant approach was to use post-grafting immunosuppression with MMF/CSP, not only for better control of graft-versus-host disease (GVHD), but also to suppress host-versus-graft reactions. This way, the intensity of the conditioning programs could be reduced. Combing the new principal with previously published observations, we have shown that DLA- haploidentical HSCT could be almost uniformly established after only 450 cGy TBI when drugs were given, in addition, an anti-CD44 monoclonal antibody (Mab, S5) before transplant. We plan to lower the TBI dose to the sublethal range of 200 cGy and to obtain better control of GVHD in this model by evaluating three distinctly different approaches: (1) extending post-grafting MMF/CSP from the previously used 28 and 35 days, respectively to 100 days; (2) evaluating an antagonist to LFA1 (leukocyte functional antigen-1) peritransplant; and (3) adding T cell co- stimulatory blockade with CTLA4lg+/- an Mab to CD154 (CD40 ligand) to the regimen. In DLA-identical littermates, we will examine whether targeted irradiation firm a short-lived alpha-emitting radionuclide, Bismuth 213 (Bi-213), delivered through appropriate MAbs can be substituted for 200 cGy external beam TBI in providing immunosuppression necessary for engraftment. We will first target host cells with a pan-hematopoietic anti-CD45 antibody, and then test T cell- specific ablation with an anti-T cell receptor antibody. Successful strategies will be used in combination with the goal of completely replacing TBI with less toxic immunosuppression regimens.