Fraser C C, Kaneshima H, Hansteen G, Kilpatrick M, Hoffman R, Chen B P
Experimental Cell Therapy Group, SyStemix Inc, Palo Alto, CA 94304, USA.
Blood. 1995 Sep 1;86(5):1680-93.
The ability to determine the functional capacity of putative human hematopoietic stem cell (HSC) populations requires in vivo assays in which long-term multilineage differentiation can be assessed. We hypothesized that if human fetal bone was transplanted adjacent to a fetal thymus fragment in severe combined immunodeficient (SCID) mice, a conjoint organ might form in which HSC in the human bone marrow (BM) would mimic human multilineage differentiation into progenitor cells, B cells, and myeloid cells; undergo self-renewal; and migrate to and differentiate into T cells within the thymic microenvironment. To test this possibility, SCID mice were transplanted subcutaneously with HLA class I mismatched fetal bone, thymus, and spleen fragments (SCID-hu BTS). We found that the BM of SCID-hu BTS grafts maintained B cells, myeloid cells, CD34+ cells for at least 36 weeks posttransplant. Assayable hematopoietic progenitors colony-forming units-granulocyte-macrophage were present in 100% (66/66) of grafts over a period of 28 weeks. Cells with a HSC phenotype (CD34+Thy-1+Lin-) were maintained for 20 weeks in SCID-hu BTS grafts. These CD34+Thy-1+Lin- cells had potent secondary multilineage reconstituting potential when isolated and injected into a secondary HLA mismatched SCID-hu bone assay and analyzed 8 weeks later. In addition, early progenitors within the BM of SCID-hu BTS grafts were capable of migrating to the human thymus and undergoing differentiation through immature CD4+CD8+ double-positive T cells and produce mature T cells with a CD4+CD8- or CD8+CD4- phenotype that could be detected for at least 36 weeks. Phenotypically defined human fetal liver (FL) and umbilical cord blood (UCB) hematopoietic stem cell populations were injected into irradiated SCID-hu BTS grafts to assess their multilineage repopulating capacity and to assess the ability of the BTS system to provide an environment where multiple lineages might differentiate from a common stem cell pool. Injection of irradiated grafts with FL HSC or UCB HSC cells resulted in donor-derived B cells, myeloid cells, immature and mature T cells, and CD34+ cells in individual grafts when analyzed 8 weeks postreconstitution, further showing the multipotential nature of these stem cell populations. In addition, a strong correlation was observed between maintenance of host graft-derived CD8+ cells and failure of donor stem cell engraftment.(ABSTRACT TRUNCATED AT 400 WORDS)
确定假定的人类造血干细胞（HSC）群体功能能力的方法需要进行体内试验，在这种试验中可以评估长期多谱系分化情况。我们推测，如果将人类胎儿骨骼移植到严重联合免疫缺陷（SCID）小鼠的胎儿胸腺片段附近，可能会形成一个联合器官，其中人类骨髓（BM）中的HSC会模拟人类多谱系分化为祖细胞、B细胞和髓系细胞；进行自我更新；并迁移到胸腺微环境中分化为T细胞。为了验证这种可能性，将HLA I类不匹配的胎儿骨骼、胸腺和脾脏片段皮下移植到SCID小鼠体内（SCID-hu BTS）。我们发现，SCID-hu BTS移植物的BM在移植后至少36周内维持了B细胞、髓系细胞和CD34+细胞。在28周的时间里，100%（66/66）的移植物中存在可检测的造血祖细胞集落形成单位-粒细胞-巨噬细胞。具有HSC表型（CD34+Thy-1+Lin-）的细胞在SCID-hu BTS移植物中维持了20周。当这些CD34+Thy-1+Lin-细胞被分离并注射到二次HLA不匹配的SCID-hu骨试验中，并在8周后进行分析时，它们具有强大的二次多谱系重建潜力。此外，SCID-hu BTS移植物BM中的早期祖细胞能够迁移到人类胸腺，并通过未成熟的CD4+CD8+双阳性T细胞进行分化，产生具有CD4+CD8-或CD8+CD4-表型的成熟T细胞，这种情况至少可以检测36周。将表型定义的人类胎儿肝脏（FL）和脐带血（UCB）造血干细胞群体注射到经照射的SCID-hu BTS移植物中，以评估它们的多谱系重建能力，并评估BTS系统提供一个多种谱系可能从共同干细胞池中分化出来的环境的能力。在重建后8周进行分析时，向经照射的移植物中注射FL HSC或UCB HSC细胞，导致各个移植物中出现供体来源的B细胞、髓系细胞、未成熟和成熟T细胞以及CD34+细胞，进一步证明了这些干细胞群体的多能性。此外，在宿主移植物来源的CD8+细胞的维持与供体干细胞植入失败之间观察到了强烈的相关性。（摘要截断于400字）
