摘要目的 探讨抗T免疫毒素(IT)体外对脐血T细胞的清除效率及对造血干/祖细胞的影响。方法 (1)用碱性磷酸酶抗碱性磷酸酶桥联酶标技术法(APAAP)分别测定了脐血、骨髓、外周血标本CD5+、CD8+T细胞的百分率;(2)用单向混合淋巴细胞培养(MLC)比较了外周血与脐血MLC增殖反应;(3)分别用MLC法和噻唑兰比色法(MTT)观察了两组抗人白细胞分化抗体(CD5+、CD8+)与完整蓖麻毒素(Ricin)偶联制备的两组免疫毒素(CD5:Ricin及CD8:Ricin)对脐血T细胞增殖反应及对T淋巴转化功能抑制的影响;(4)用造血祖细胞培养的方法观察两组种免疫毒素对粒单系祖细胞(CFU-GM)、早期红系祖细胞(BFU-E)及混合系祖细胞(CFU-Mix)的影响。 结果 (1)脐血含有一定比例的CD5+及CD8+T细胞亚群;(2)在MLC中外周血与脐血对异源抗原的增殖反应相似;(3)CD5:Ricin在1×10-10-1×10-8mmol/L、CD8:Ricin在1×10-9-1×10-8mmol/L浓度范围内均能有效降低脐血T淋巴细胞在MLC中的增殖反应,并能有效抑制T淋巴细胞转化功能;(4)两组IT在1×10-10-1×10-9mmol/L浓度下对三种造血祖细胞增殖反应无明显影响。 结论 CD5:Ricin及CD8:Ricin在一定剂量范围内可以安全有效地去除脐血中T细胞，并且对造血祖细胞无明显影响。

abstractsObjective To study the selective toxicity of immunotoxin (IT) onT cells in cord blood and simultaneously determine its effect on hematopoietic progenitor cells. Methods The percentage of CD5 and CD8 T cell subsets in cord blood (CB) and bone marrow (BM) as well as peripheral blood (PB) was measured by immunoenzymatic labeling of monoclonal antibodies using immune complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase (APAAP complexes). One-way mixed lymphocyte cultures (MLC) were performed to compare the proliferative response of CB with that of PB. The proliferative capability of cord blood T cells and T lymphocyte transformation capacity were evaluated in the presence of anti-CD8 or anti-CD5 immunotoxin by one-way MLC and colorimetric MTT (tetrazolium) assay, respectively. The effect of IT on the growth of hematopoietic progenitor cell of colony forming unit-granulocyte and macrophage (CFU-GM), burst forming unit-erythroid(BFU-E), multipotential hemotapoietic progenitors (CFU-Mix) from CB were estimated by colony-forming assays. Results A certain proportion of CD5 and CD8 T cells existed in CB. The alloproliferative capacity of CB was similar to that of PB. CD5: Ricin at a dosage of 1×10-10-1×10-8 mmol/L and CD8: Ricin concentration in the range of 1×10-9-1×10-8 mmol/L effectively decreased both the proliferative capability of T cells in MLC during CB and T cell transformation. Over the dosage of 1×10-10-1×10-9 mmol/L, both kinds of IT didn't obviously affect the growth of hematopoietic progenitor cells. Conclusion CD5: Ricin and CD8: Ricin may effectively deplete T cells and may not significantly inhibit the function of hemaptopoietic cells at a specific dosage.