Defranco A L, Raveche E S, Asofsky R, Paul W E
J Exp Med. 1982 May 1;155(5):1523-36. doi: 10.1084/jem.155.5.1523.
The frequency of murine B lymphocytes that respond to antibodies directed against membrane IgM was measured. These anti-mu antibodies induced all, or almost all, resting B cells to enlarge over the first 24 h of stimulation. This probably represents the transition from the resting state (G0) to active transit through the cell cycle. In contrast, only a fraction of these cells, approximately 60% for BDF1 mice, continued through the cell cycle into S phase. This is consistent with previous experiments that had suggested there were some types of B cells that did not proliferate in response to anti-mu. The results presented here demonstrate that many, perhaps all, of these nonresponding B cells, both from normal mice and from mice with the xid defect, actually do respond to the presence of anti-mu by going through early parts of the cell cycle. These cells appear to become blocked at some point before the beginning of S phase, perhaps requiring a signal from a T cell or a macrophage to continue through the cell cycle. Thus, the role of antigen may be to prepare all B cells for proliferation. Different subpopulations of B cells may then require different regulatory signals before actually proliferating or before differentiating into antibody-secreting cells.
对响应针对膜IgM的抗体的小鼠B淋巴细胞频率进行了测定。这些抗μ抗体在刺激的最初24小时内诱导所有或几乎所有静止B细胞增大。这可能代表从静止状态（G0）到细胞周期中活跃过渡的转变。相比之下，这些细胞中只有一部分，对于BDF1小鼠约为60%，继续通过细胞周期进入S期。这与先前的实验一致，那些实验表明存在一些类型的B细胞不会对抗μ作出增殖反应。此处呈现的结果表明，来自正常小鼠和有xid缺陷的小鼠的许多（也许是所有）这些无反应B细胞，实际上确实会通过经历细胞周期的早期阶段来对抗μ的存在作出反应。这些细胞似乎在S期开始前的某个点被阻断，可能需要来自T细胞或巨噬细胞的信号才能继续通过细胞周期。因此，抗原的作用可能是使所有B细胞做好增殖准备。然后，不同亚群的B细胞在实际增殖或分化为抗体分泌细胞之前可能需要不同的调节信号。
