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B淋巴细胞的来源个体发生过程中,首先在肝脏中出现B细胞早期发生的证据:先出现胞浆IgM(c-IgM)阳性细胞;其次是表面IgM(sIgM)阳性细胞;C3受体阳性细胞的出现最迟。景近,Melchers的观察说明在胎盘中,B细胞发生可能出现得更早,出生后,绝大多数B细胞均衍生于骨髓。染色体标志研究显示,与其它血细胞一样,所有的淋巴细胞均衍生于多能造血干细胞。就T细胞而育,可能存在一种定向T前体细胞。定向B前体细胞的存在尚无证据,B细胞可能直接继嗣于干细胞库。一种设想认为,前T细胞必需迁移至胸腺才能进一步分化,而B细胞早期分化可能仅限于在骨髓微环境中进行。目前,尚不能肯定骨髓微环境是B细胞发生的必需条件。就此而言,
In the process of B lymphocyte origination, firstly, there is evidence of early appearance of B cells in the liver: first cytoplasmic IgM (c-IgM) positive cells; secondly surface IgM (sIgM) positive cells; C3 receptor positive cells The emergence of the latest. King’s recent observations by Melchers suggest that B-cell development may occur earlier in the placenta and that most B-cells are derived from the bone marrow at birth. Chromosome marker studies have shown that, like other blood cells, all lymphocytes are derived from pluripotent hematopoietic stem cells. T cells on the breeding, there may be a directional T precursor cells. There is no evidence for the existence of targeted B precursor cells, which may directly follow the stem cell pool. One hypothesis is that pre-T cells must migrate to the thymus for further differentiation, whereas B-cell early differentiation may be limited to the bone marrow microenvironment. At present, it is not yet certain that the bone marrow microenvironment is a necessary condition for B cell development. In this regard,