目的：探讨运用反义ＲＮＡ技术降低脐血细胞ＭＨＣ－Ⅱ类基因的表达是否能有效减少ＧＶＨＲ发生的危险程度，为临床上进行脐血移植降低脐血干细胞的移植物抗宿主反应提供了理论依据和实验基础。方法：应用分子克隆技术构建了含人ＨＬＡ－ＤＲβ基因的逆转录病毒表达载体，经过狭缝杂交、电泳分析、酶切图谱分析鉴定。结果：获得了ＨＬＡ－ＤＲβ基因反义ＲＮＡ重组体。结论：构建人ＭＨＣ－Ⅱ类基因反义ＲＮＡ的逆转录病毒重组体，为进一步探讨运用反义ＲＮＡ技术降低脐血细胞的免疫原性奠定了工作基础 OBJECTIVE: To investigate whether the use of antisense RNA technology to reduce the expression of MHC-Ⅱ gene in umbilical cord blood cells can effectively reduce the risk of GVHR and provide a theoretical basis for reducing the graft-versus-host reaction of umbilical cord blood stem cells in cord blood transplantation in clinical practice. Experimental basis. Methods: The recombinant retroviral vector containing human HLA-DRβ gene was constructed by molecular cloning technique. The recombinant plasmid was identified by slit-blot, electrophoresis and restriction enzyme digestion. Results: The recombinant HLA-DRβ antisense RNA was obtained. CONCLUSION: The construction of recombinant retrovirus containing human antisense RNA of human MHC class II gene provides a basis for further study on the use of antisense RNA technology to reduce the immunogenicity of cord blood cells