Deenen G J, Hunt S V, Opstelten D
J Immunol. 1987 Aug 1;139(3):702-10.
In rat bone marrow (BM), the B lineage surface antigen HIS24 is expressed by all surface mu chain-bearing (s mu+) B cells, by cytoplasmic mu chain-containing (c mu+s mu-) pre-B cells and TdT+ cells, and by lymphoid cells lacking both mu and TdT. Because TdT+ and HIS24+TdT-mu- cells may represent stages in B lymphocytopoiesis before mu chain expression, we investigated their kinetics. The metaphase arrest method was combined with immunofluorescence staining to detect proliferation and to quantitate cell production in the BM pre-B, TdT+, and HIS24+TdT-mu- compartments. Their apparent cell cycle times (tC(a)) were 38, 36, and 19 hr, and the number of cells produced per hour per femur were 58, 9, and 41 X 10(4), respectively. The HIS24+ compartments showed further phenotypic heterogeneity. Six percent of TdT+ cells expressed mu chains and were therefore pre-B cells. Twenty percent of HIS24+TdT-mu- cells expressed Ig other than mu chains, with size distribution and kinetics similar to HIS24+TdT-Ig- cells. Thus, the rate of production in the truly Ig-HIS24+ compartment was about 40 X 10(4)/hr/femur (8.5 by TdT+mu- and 33 by TdT-Ig-). In each phenotypic compartment, mitoses were confined to subsets of large (greater than 11 to 12 micron) cells with tC(a) of 13 to 15 hr. Surface mu+ B cells were essentially non-cycling. To quantitate whole body BM cell production, the recovery of marrow from bone and the distribution of BM were measured in 59Fe distribution experiments. The number of cells produced by whole body BM was estimated as follows: for pre-B cells, 4.5 X 10(8)/day; for TdT+mu-, 0.7 X 10(8)/day; and for HIS24+TdT-Ig- 2.6 X 10(8)/day. From the derived cell flux in these compartments we suggest that 1) many more pre-B cells are produced than needed by the peripheral B cell pool; 2) if TdT is an obligatory stage in B cell genesis, there must be at least two cell cycles in the pre-B cell compartment; 3) if it is not, the TdT+ stage may be bypassed, with HIS24+TdT-Ig- cells perhaps feeding directly into the pre-B cell compartment.
在大鼠骨髓（BM）中，B细胞系表面抗原HIS24由所有带有表面μ链（sμ+）的B细胞、含细胞质μ链（cμ+sμ-）的前B细胞和TdT+细胞以及既缺乏μ链又缺乏TdT的淋巴细胞表达。由于TdT+和HIS24+TdT-μ-细胞可能代表μ链表达之前的B淋巴细胞生成阶段，我们研究了它们的动力学。中期阻断法与免疫荧光染色相结合，以检测增殖并定量BM前B细胞、TdT+细胞和HIS24+TdT-μ-区室中的细胞生成。它们的表观细胞周期时间（tC(a)）分别为38、36和19小时，每小时每条股骨产生的细胞数分别为58、9和41×10(4)。HIS24+区室表现出进一步的表型异质性。6%的TdT+细胞表达μ链，因此是前B细胞。20%的HIS24+TdT-μ-细胞表达除μ链以外的Ig，其大小分布和动力学与HIS24+TdT-Ig-细胞相似。因此，真正的Ig-HIS24+区室中的产生速率约为40×10(4)/小时/股骨（TdT+μ-为8.5，TdT-Ig-为33）。在每个表型区室中，有丝分裂局限于大细胞（大于11至12微米）亚群，其tC(a)为13至15小时。表面μ+B细胞基本上不进行细胞周期循环。为了定量全身BM细胞生成，在59Fe分布实验中测量了从骨中回收的骨髓和BM的分布。全身BM产生的细胞数估计如下：前B细胞为4.5×10(8)/天；TdT+μ-为0.7×10(8)/天；HIS24+TdT-Ig-为2.6×10(8)/天。根据这些区室中得出的细胞通量，我们认为：1）产生的前B细胞比外周B细胞库所需的多得多；2）如果TdT是B细胞发生中的一个必经阶段，前B细胞区室中必定至少有两个细胞周期；3）如果不是，TdT+阶段可能被绕过，HIS24+TdT-Ig-细胞可能直接进入前B细胞区室。
