Bruno B, Nash R A, Wallace P M, Gass M J, Thompson J, Storb R, McSweeney P A
Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
Transplantation. 1999 Aug 15;68(3):338-44. doi: 10.1097/00007890-199908150-00004.
Canine stem cell transplantation models have provided important preclinical information for human clinical studies. The recent cloning of cDNA for canine CD34 and the production of monoclonal antibodies that recognize canine CD34 have been the basis for the development of techniques for the large-scale enrichment of canine hematopoietic progenitor cells. In this study, we evaluated the in vivo functional properties of canine bone marrow CD34+ cells after a myeloablative conditioning regimen.
After 920 cGy total body irradiation, three dogs received infusion of autologous CD34+ selected cells from the marrow, three dogs CD34+ depleted autologous marrow cells, and two dogs received CD34+ autologous marrow cells that were immunomagnetically selected and then further purified by cell sorting. In addition, four dogs received allogeneic marrow enriched for CD34+ cells from dog leukocyte antigen-identical littermates to investigate long-term repopulating function of CD34+ cells. Chimerism studies were performed using polymerase chain reaction to detect highly polymorphic microsatellite markers.
In three recipients of autologous marrow enriched for CD34+ cells to between 29% and 70% (1.6 x 10(6) to 3.4x10(6) CD34+ cells/kg), prompt and full hematopoietic recovery occurred, whereas in three dogs that received marrow depleted of CD34+ cells (1 x 10(7) cells/kg), no hematopoietic recovery was achieved. In two dogs that received highly purified CD34+ cells (purity: 98% and 96%, 0.79x10(6) to 0.547x 10(6) CD34+ cells/kg), delayed but full hematopoietic recovery was seen. Three of four allograft recipients of 1.75x10(6) to 6.8x10(6) CD34+ cells/kg engrafted and showed full hematopoietic recovery, whereas one dog rejected the graft. The three long-term survivors showed stable mixed hematopoietic chimerism with predominantly donor hematopoiesis.
Transplantation of canine CD34+ cells after lethal total body irradiation provides radioprotection and gives rise to long-term hematopoietic reconstitution. Stable donor/host mixed chimerism was observed in allograft recipients most likely as a result of T-cell depletion of the grafts. Our findings suggest a future role for canine preclinical transplant studies involving in vitro manipulation of hematopoietic pro.
犬类干细胞移植模型为人类临床研究提供了重要的临床前信息。犬类CD34的cDNA的近期克隆以及识别犬类CD34的单克隆抗体的产生，已成为大规模富集犬类造血祖细胞技术发展的基础。在本研究中，我们评估了清髓预处理方案后犬类骨髓CD34+细胞的体内功能特性。
在920 cGy全身照射后，三只犬接受了来自骨髓的自体CD34+选择细胞的输注，三只犬接受了CD34+耗尽的自体骨髓细胞，两只犬接受了经免疫磁珠选择然后通过细胞分选进一步纯化的CD34+自体骨髓细胞。此外，四只犬接受了来自犬白细胞抗原相同的同窝仔犬的富含CD34+细胞的同种异体骨髓，以研究CD34+细胞的长期重建功能。使用聚合酶链反应进行嵌合研究，以检测高度多态性的微卫星标记。
在三只接受富含CD34+细胞的自体骨髓的受体中，CD34+细胞富集至29%至70%（1.6×10⁶至3.4×10⁶个CD34+细胞/kg），造血迅速且完全恢复，而在三只接受耗尽CD34+细胞的骨髓（1×10⁷个细胞/kg）的犬中，未实现造血恢复。在两只接受高度纯化的CD34+细胞（纯度分别为98%和96%，0.79×10⁶至0.547×10⁶个CD34+细胞/kg）的犬中，观察到造血恢复延迟但完全恢复。四只接受1.75×10⁶至6.8×10⁶个CD34+细胞/kg的同种异体移植受体中有三只植入并显示出完全的造血恢复，而一只犬排斥了移植物。三名长期存活者表现出稳定的混合造血嵌合，主要为供体造血。
致死性全身照射后移植犬类CD34+细胞可提供辐射防护并实现长期造血重建。在同种异体移植受体中观察到稳定的供体/宿主混合嵌合，最可能是由于移植物的T细胞耗竭。我们的研究结果表明，犬类临床前移植研究在涉及造血前体细胞的体外操作方面具有未来作用。
