Rolink A G, Andersson J, Melchers F
Basel Institute for Immunology, Switzerland.
Eur J Immunol. 1998 Nov;28(11):3738-48. doi: 10.1002/(SICI)1521-4141(199811)28:11<3738::AID-IMMU3738>3.0.CO;2-Q.
The transit of immature to mature sIgM+ B cells, the life span, maturation kinetics and response to polyclonal activators have been analyzed with the help of a new mAb (493), that distinguishes immature, 493+ from mature, 493 B cells in a variety of mouse strains tested. Analysis of the turnover of immature 493+ B cells by bromodeoxyuridine (BrdU) labeling kinetics indicate that only 10-20 % of the cells reach the spleen as immature 493+ cells. The life span of 493+ B cells in bone marrow and spleen is around 4 days. BrdU chase experiments show that most of the immature cells in spleen enter the pool of mature, 493+ B cells where they gain a longer life span of 15-20 weeks. Immature and mature B cells respond equally well to LPS stimulation; anti-CD40, however, stimulates mature B cells better than immature B cells. IgM cross-linking of mature B cells results in proliferation, while it induces apoptosis in immature B cells. This apoptosis of immature cells can be inhibited by costimulation with anti-CD40 or by overexpression of bcl-2. We speculate that Ig receptor ligand-mediated apoptosis (negative selection) plays a major role in the transit of immature B cells from bone marrow to spleen, but only a minor role in the transit from immature B cells to mature B cells in the spleen.
借助一种新的单克隆抗体（493），对未成熟至成熟的sIgM+B细胞的转变、寿命、成熟动力学以及对多克隆激活剂的反应进行了分析。在多种测试的小鼠品系中，该抗体可区分未成熟的493+细胞和成熟的493细胞。通过溴脱氧尿苷（BrdU）标记动力学分析未成熟493+ B细胞的更新情况，结果表明只有10%-20%的细胞以未成熟493+细胞的形式到达脾脏。493+ B细胞在骨髓和脾脏中的寿命约为4天。BrdU追踪实验表明，脾脏中的大多数未成熟细胞进入成熟的493+ B细胞池，在那里它们获得了15-20周的更长寿命。未成熟和成熟B细胞对LPS刺激的反应同样良好；然而，抗CD40对成熟B细胞的刺激优于未成熟B细胞。成熟B细胞的IgM交联导致增殖，而在未成熟B细胞中则诱导凋亡。未成熟细胞的这种凋亡可通过抗CD40共刺激或bcl-2的过表达来抑制。我们推测，Ig受体配体介导的凋亡（阴性选择）在未成熟B细胞从骨髓向脾脏的转变中起主要作用，但在脾脏中从未成熟B细胞向成熟B细胞的转变中仅起次要作用。
