Hirano T, Teranishi T, Lin B, Onoue K
J Immunol. 1984 Aug;133(2):798-802.
At least two distinct B cell stimulatory factors (BSF) were found to be involved in the differentiation of Staphylococcus aureus Cowan I (SAC)-stimulated human B cells to IgG-producing cells. A factor tentatively called B cell differentiation factor I (BCDF I) was found in one fraction, and a second factor, BCDF II was found in another fraction. The BCDF I fraction alone induces IgG-production in SAC-stimulated B cells, but the BCDF II fraction does not. The BCDF II fraction enhances IgG production in SAC-stimulated B cells in the presence of the BCDF I fraction. Studies concerning the time-course of the action of the BCDF II fraction revealed that it contains a late-acting differentiation factor that acts on B cells most effectively when it is added to the SAC-stimulated B cell culture after the addition of BCDF I fraction; it induces IgG plaque-forming cells within 1 day. The pI value of a late-acting BCDF was in the range of 5 to 6; this pI range is different from that of BCDF I but similar to that of BCDF II, which was shown in our previous studies to be able to induce IgG production in Epstein Barr Virus-transformed B lymphoblastoid cell lines. In addition, the m.w. of a late-acting BCDF were about 35,000 and 20,000, which are the same as those of BCDF II, and thus its identity with BCDF II was suggested.
已发现至少两种不同的B细胞刺激因子（BSF）参与金黄色葡萄球菌考恩I型（SAC）刺激的人B细胞向产生IgG细胞的分化过程。在一个组分中发现了一种暂称为B细胞分化因子I（BCDF I）的因子，在另一个组分中发现了第二种因子，即BCDF II。单独的BCDF I组分可诱导SAC刺激的B细胞产生IgG，但BCDF II组分则不能。在存在BCDF I组分的情况下，BCDF II组分可增强SAC刺激的B细胞产生IgG的能力。关于BCDF II组分作用时间进程的研究表明，它含有一种晚期作用的分化因子，当在加入BCDF I组分后再添加到SAC刺激的B细胞培养物中时，对B细胞的作用最为有效；它可在1天内诱导产生IgG空斑形成细胞。晚期作用的BCDF的pI值在5至6的范围内；这个pI范围与BCDF I不同，但与BCDF II相似，在我们先前的研究中表明BCDF II能够在爱泼斯坦-巴尔病毒转化的B淋巴母细胞系中诱导产生IgG。此外，晚期作用的BCDF的分子量约为35,000和20,000，与BCDF II相同，因此提示它与BCDF II是同一物质。
