Study Of Human Immune Reconstitution On NOD/SCID Mice Transplanted With Human Cord Blood Hematopoietic Stem Cell

ObjectiveTo explore conditions for cord blood(CB) hematopoietic stem cells engrafed in NOD/SCID mice, Hu-SRC-NOD/SCID mice model was established and the level of immune and hematopoietic reconstitution were assessed in this model. Study of this model is very helpful to assessment of vaccine and drug responses.MethodsMononuclear cells(MNC) and CD34⁺ cells were isolated or sorted from CB.Non-irradiated or sublethally irradiated(⁶⁰Co, 300cGy) NOD/SCID mice were transplanted intraverously with CB MNC or CD34⁺cells. Human CD45,CD19,CD3 markers on cells from murine PB, bone marrow, thymus were detected by FCM from 4 to 10 weeks after transplantation. After 6 weeks , RNA was obtained from bone marrow, thymus of model . The gene expression and clonality of TCR Vβ repertoire were detected by RT-PCR and genescan technique respectively. After 10 weeks , the human MHC-β₂m and Rag2 was detected by RT-PCR in PB or bone marrow of mice. To assess immunogenicity of NOD/SCID mice , the cells from PB MNC and BM, spleen, thymus in NOD/SCID mice were wiped off by freeze thawing. CB MNC were separately cultured with the component from those murine cells for 2 to 3 weeks.The RNA expression and cloanlity of TCR Vβ repertoire were detected by RT-PCR and genescan technique.ResultsSufficient CD34⁺ cells were enricheded from CB MNC by using MACS, the purity ofSRC is 80 ～95%. The levels of human cell engraftment in irradiated mice...