Birkeland M L, Simpson L, Isakson P C, Pure E
J Exp Med. 1987 Aug 1;166(2):506-19. doi: 10.1084/jem.166.2.506.
Sepharose-anti-Ig and purified populations of small, high-density B cells have been used to study the formation and function of B lymphoblasts. Sepharose-anti-Ig converts small, Ia-poor B cells with a high-buoyant density to large, Ia-rich, B blasts with a low-buoyant density. We find that this response proceeds efficiently in the absence of IL-4 (BSF-1) as well as most T cells, macrophages, and dendritic cells. Further development of the blasts requires an additional stimulus, such as LPS or the conditioned medium of stimulated EL-4 thymoma cells. Within 6 h, blasts begin to enter S phase and within 24 h most divide. At later times (48-72 h) most of the blasts are actively secreting IgM. Recombinant IL-1, -2, -3, and -4 have little or no effect on the B blasts, and a neutralizing mAb to IL-4 does not block the response to EL-4 Sn. We conclude that Sepharose-anti-Ig induces B cell blastogenesis in a T-independent fashion and that these blasts represent a highly enriched population of cells that respond to distinct, T cell-derived lymphokines.
琼脂糖抗免疫球蛋白（Sepharose - anti - Ig）和纯化的小而高密度B细胞群体已被用于研究B淋巴母细胞的形成和功能。琼脂糖抗免疫球蛋白将具有高浮力密度、Ia抗原含量低的小B细胞转化为具有低浮力密度、Ia抗原丰富的大B母细胞。我们发现，在没有白细胞介素-4（IL - 4，即B细胞刺激因子-1，BSF - 1）以及大多数T细胞、巨噬细胞和树突状细胞的情况下，这种反应仍能高效进行。母细胞的进一步发育需要额外的刺激，如脂多糖（LPS）或受刺激的EL - 4胸腺瘤细胞的条件培养基。在6小时内，母细胞开始进入S期，24小时内大多数母细胞进行分裂。在更晚些时候（48 - 72小时），大多数母细胞开始活跃分泌免疫球蛋白M（IgM）。重组白细胞介素-1、-2、-3和-4对B母细胞几乎没有影响，并且针对IL - 4的中和单克隆抗体不能阻断对EL - 4上清液的反应。我们得出结论，琼脂糖抗免疫球蛋白以不依赖T细胞的方式诱导B细胞形成母细胞，并且这些母细胞代表了对不同的、T细胞衍生的淋巴因子有反应的高度富集的细胞群体。
