Lamelin J P, Vassalli P
Ann Immunol (Paris). 1975 Oct-Dec;126(5-6):523-39.
When murine lymphoid cells from spleen and lymph nodes were cultured with LPS, all the transformed blasts observed were B cells bearing surface IgM which could be classified into two types depending upon whether they contained intracellular IgM (i mu +) or not (i mu -). At the ultrastructural level, the two categories of blasts appeared to correspond to cells having a well-developed ER or primarily free ribosomes. A striking observation was that the proportion of i mu + blasts among transformed cells was 5-10 times lower in cultures of lymph node than in cultures of spleen cells. The same observations were made on LPS cultures of "purified" B lymphocytes. Prolongation of the culture period did not modify these results. This indicated that the differences in the response to LPS reflected the existence of at least two pre-existing subpopulations of B cells unequally distributed in peripheral lymphoid organs. Analysis of the surface antigens and receptors (MBLA, surface Ig classes, Fc and C receptors) of the B cells from spleen and lymph nodes did show some differences between these two lymphoid organs. Among the transformed cells, Fc receptors were present mainly on i mu - cells and C receptors on i mu + cells; however, no strict correlation could be made between the i mu + or i mu - nature of these cells and their surface characteristics. The possibility that precursors of i mu + and i mu - blasts might represent virgin and memory B cells or B cell populations differing in their requirement for helper factors released by stimulated T cells was explored by using cultures of spleen and lymph node cells (1) obtained from germ-free mice, which are expected to have few memory cells, or (2) performed in the presence of the supernatant of mixed lymphocyte cultures, in conditions where these supernatants are known to contain factors released by activated T cells. Neither condition modified the degree of transformation or Ig content of blasts.
当用脂多糖（LPS）培养来自脾脏和淋巴结的小鼠淋巴细胞时，观察到的所有转化母细胞均为带有表面免疫球蛋白M（IgM）的B细胞，根据其细胞内是否含有IgM（iμ +）可分为两种类型。在超微结构水平上，这两类母细胞似乎分别对应于内质网发达或主要含游离核糖体的细胞。一个显著的观察结果是，在淋巴结培养物中，转化细胞中iμ +母细胞的比例比脾细胞培养物中的低5至10倍。在“纯化”B淋巴细胞的LPS培养物中也得到了相同的观察结果。延长培养时间并未改变这些结果。这表明对LPS反应的差异反映了外周淋巴器官中至少存在两种预先存在的B细胞亚群，其分布不均。对脾脏和淋巴结B细胞的表面抗原和受体（MBLA、表面Ig类别、Fc和C受体）的分析确实显示了这两个淋巴器官之间存在一些差异。在转化细胞中，Fc受体主要存在于iμ -细胞上，C受体存在于iμ +细胞上；然而，这些细胞的iμ +或iμ -性质与其表面特征之间没有严格的相关性。通过使用从无菌小鼠获得的脾脏和淋巴结细胞培养物（1）（预计无菌小鼠几乎没有记忆细胞）或（2）在混合淋巴细胞培养物上清液存在的条件下进行培养（已知这些上清液含有活化T细胞释放的因子），探讨了iμ +和iμ -母细胞的前体可能代表原始B细胞和记忆B细胞或对刺激T细胞释放的辅助因子需求不同B细胞群体的可能性。这两种情况均未改变母细胞的转化程度或Ig含量。
