Shizuru J A, Jerabek L, Edwards C T, Weissman I L
Department of Medicine, Stanford University School of Medicine, CA 94305, USA.
Biol Blood Marrow Transplant. 1996 Feb;2(1):3-14.
Allogeneic bone marrow transplantation currently plays a critical role in the treatment of leukemias and inherited disorders of hematopoiesis, and it shows great promise for the treatment of numerous other diseases. The problems of graft-vs-host disease (GVHD) and failure to engraft, however, remain formidable obstacles to the widespread use of this therapy. Successful transplantation of purified populations of hematopoietic stem cells (HSCs) can theoretically avoid the problem of GVHD, since purified HSCs lack the mature elements that allow the graft to mount a response against the host. In previous studies from our laboratory, a population of purified HSCs (Thy-1loLin-/loSca-1+) was isolated from mouse bone marrow (BM). These cells represent approximately 0.05% of BM cells and are capable of self-renewal and long-term reconstitution of all blood lineages. Here we report long-term engraftment of these purified HSCs transplanted in mice across successively more difficult allogeneic-histocompatibility barriers. Transplantation of purified HSCs were quantitatively compared with whole bone marrow (WBM) grafts containing equivalent numbers of stem cells. The mouse strain combinations tested were parent transplanted into F1 (Hh disparate), minor histocompatibility complex (mHC), and major histocompatibility complex (MHC) plus mHC disparities. One of the recipient strains studied for MHC-disparate transplantations was that of spontaneously autoimmune diabetic mice. Recipient mice were administered lethal doses of whole-body irradiation in the presence or absence of antibodies directed against natural killer (NK) cell-associated determinants and/or monoclonal antibodies against the CD4+ T cell subset. We find that as the barrier to transplantation increases, greater numbers of HSCs are required for radioprotection and engraftment. In all cases, stable hematopoietic chimeras were generated with HSCs alone, but 10-60 times the number of HSCs was required for radioprotection of mice transplanted across allogeneic or semiallogeneic disparities as compared to Ly-5 congenic differences. Furthermore, we demonstrate a clear advantage of WBM vs HSCs with regard to tha ability to engraft [corrected]. Chimeric mice showed no symptoms of GVHD, and their T cells were unable to induce GVHD in neonatal mice expressing H-2 antigens of donor and host. These data confirm that a cell population resident in WBM and distinct from purified stem cells is important in facilitating hematopoietic engraftment, in this case, of purified allogeneic HSCs. The differences in engraftment between WBM and HSCs could be reduced significantly by the addition of antibodies directed against NK determinants to the host preparative regimen. Similarly, since antibodies directed against host NK-associated antigens can reduce the barrier to allogeneic HSC engraftment, an interaction between the facilitating population within donated WBM and a resistant host population with NK determinants is implied.
目前，异基因骨髓移植在白血病和遗传性造血系统疾病的治疗中发挥着关键作用，并且在治疗许多其他疾病方面也显示出巨大的潜力。然而，移植物抗宿主病（GVHD）和植入失败问题仍然是这种疗法广泛应用的巨大障碍。从理论上讲，成功移植纯化的造血干细胞（HSC）群体可以避免GVHD问题，因为纯化的HSC缺乏使移植物对宿主产生反应的成熟细胞成分。在我们实验室之前的研究中，从小鼠骨髓（BM）中分离出了一群纯化的HSC（Thy-1loLin-/loSca-1+）。这些细胞约占BM细胞的0.05%，能够自我更新并长期重建所有血细胞谱系。在此，我们报告了这些纯化的HSC在小鼠体内跨越相继更难的异基因组织相容性屏障进行移植后的长期植入情况。将纯化的HSC移植与含有等量干细胞的全骨髓（WBM）移植物进行了定量比较。所测试的小鼠品系组合包括亲代移植到F1（Hh不匹配）、次要组织相容性复合体（mHC）以及主要组织相容性复合体（MHC）加mHC不匹配。针对MHC不匹配移植研究的受体品系之一是自发自身免疫性糖尿病小鼠。受体小鼠在有或没有针对自然杀伤（NK）细胞相关决定簇的抗体和/或针对CD4+T细胞亚群的单克隆抗体的情况下接受致死剂量的全身照射。我们发现，随着移植屏障的增加，为实现辐射防护和植入需要更多数量的HSC。在所有情况下，单独使用HSC均可产生稳定的造血嵌合体，但与Ly-5同基因差异相比，跨越异基因或半异基因不匹配进行移植的小鼠实现辐射防护所需的HSC数量要多10 - 60倍。此外，我们证明了在植入能力方面WBM相对于HSC具有明显优势[已修正]。嵌合小鼠未表现出GVHD症状，并且它们的T细胞无法在表达供体和宿主H-2抗原的新生小鼠中诱导GVHD。这些数据证实，存在于WBM中且与纯化干细胞不同的细胞群体对于促进纯化的异基因HSC的造血植入非常重要。通过在宿主预处理方案中添加针对NK决定簇的抗体，WBM和HSC之间的植入差异可显著降低。同样，由于针对宿主NK相关抗原的抗体可以降低异基因HSC植入的屏障，这意味着捐赠的WBM中的促进群体与具有NK决定簇的抗性宿主群体之间存在相互作用。
