Miller R G, Phillips R A
Fed Proc. 1975 Feb;34(2):145-50.
A rough outline of the development pathway of stem cells to B lymphocytes in mammals is beginning to emerge. The stem cell is most probably either identical to or closely related to the spleen colony-forming unit or hemopoietic stem cell. The stem cell appears not to be specificity-restricted and to lack Ig surface receptors. Whether part of B-cell development in mammals takes place in a specialized lymphoid environment, analogous to the bursa of Fabricius in birds, is still unresolved. The bone marrow does not form such an environment. The bone marrow and spleen, but not the lymph nodes, of mice contain a nondividing B-cell precursor population at an intermediate stage of development between the stem cell and B cell. This population has Ig surface receptors and is specificity-restricted. It cannot be initiated into differentiating into antibody-producing cells. However, under appropriate conditions it can give rise to functional B cells within 3 days. Newly-formed B cells (designated B1) are physically different from mature B cells (designated B2) and appear to be a dividing population of cells differentiating from the B-cell precursor to B2 nondividing cell populations.
哺乳动物中干细胞向B淋巴细胞发育途径的大致轮廓正开始显现。干细胞很可能与脾集落形成单位或造血干细胞相同或密切相关。干细胞似乎不受特异性限制且缺乏免疫球蛋白表面受体。哺乳动物中B细胞发育的一部分是否发生在类似于鸟类法氏囊的特殊淋巴环境中，仍未得到解决。骨髓并不形成这样的环境。小鼠的骨髓和脾脏而非淋巴结，含有处于干细胞和B细胞之间发育中间阶段的不分裂B细胞前体细胞群体。该群体具有免疫球蛋白表面受体且受特异性限制。它不能被启动分化为抗体产生细胞。然而，在适当条件下，它可在3天内产生功能性B细胞。新形成的B细胞（称为B1）在物理上与成熟B细胞（称为B2）不同，似乎是从B细胞前体向B2不分裂细胞群体分化的分裂细胞群体。
