致敏血清影响造血干细胞植入的实验研究

Experimental study on the effect of sensitized sera on engraftment of hematopoietic stem cells

目的研究致敏血清对造血干细胞植入的影响及其作用机制。方法将致敏血清或正常血清与供鼠C57BL／6骨髓细胞在体外孵育，洗涤后回输到经照射后的BALB／c小鼠，观察移植后受体鼠的生存情况并进行植入情况分析。检测经孵育后骨髓细胞与羊抗鼠IgG二抗结合情况，并分析孵育后骨髓细胞Annexin V凋亡表达。结果骨髓移植后，接受经致敏血清孵育骨髓细胞的10只受鼠中7只于10d左右死于骨髓衰竭，而接受正常血清孵育骨髓细胞的受鼠能长期存活。植入分析表明，接受致敏血清孵育骨髓细胞的受鼠在移植后其血常规及骨髓细胞随时间推移进行性下降，且供鼠细胞的嵌合百分比也进行性减少。经致敏血清或正常血清孵育的骨髓细胞与羊抗鼠IgG二抗结合百分比分别为（90．3±5．1）％和（5．2±2．4）％，两组差异有显著统计学意义（P〈0．01）；但在凋亡检测中发现两组差异并无统计学意义（P〉0．05）。结论致敏血清能明显降低造血干细胞的植入能力，致敏血清中的抗体能与造血干细胞表面抗原结合，但不能诱导其凋亡。

Objective To evaluate the effect of sensitized sera on engraftment of hematopoietic stem cells （HSCs） and its mechanism. Methods Bone marrow cells （BMCs） from C57BL/6 mice were incubated with sensitized sera （ group Ⅰ ） or normal sera （ group Ⅱ ）, and then washed and transplanted into irradiated BALB/c mice. The survival analysis and engraftment evaluation of the recipients were observed. The incubated BMCs were bound with goat anti mouse IgG for and labeled with AnnexinV for apoptosis detection. Results Seven out of ten recipient mice in group Ⅰ died of bone marrow failure at day 10 after transplantation, while all of those in group Ⅱ were long-term survived. Engraftment assay showed recipients blood count and BMCs progressively decreased along with time passing in group Ⅰ ; in addition, the chimeric percentage of donor cells progressively decreased as well. The percentage of BMCs binding with goat anti mouse lgG in group Ⅰ or group Ⅱ were （90.3 ± 5.1 ） % and （5.2 ± 2.4） %, respectively, and the difference was statistically significant （P 〈 0.01 ）. However, no significant difference was found in the apoptosis detection between the two groups （ P 〉 0.05 ）. Conclusion The engraftment capacity of HSCs is significantly impaired by sensitized sera, the antibodies in sensitized sera may bind to antigens expressed on HSCs but do not induce apoptosis.