Cebra J J, Cebra E R, Kotloff D B, Lebman D A, Schweitzer P A, Shahin R D
Biochem Soc Symp. 1986;51:159-72.
We have functionally defined a number of B cell subsets that likely represent B cells at different stages of development, based on the pattern of CH isotypes expressed by their clones in splenic fragment or microcultures and on those factors necessary in culture to support the growth of a clone displaying a particular isotype or set of isotypes. Our observations are consistent with isotype switching being a stochastic process which results in the occurrence of progressive isotype restriction in members of a diversifying clone. The surface marker best predictive of the pattern of isotypes a clone may secrete is the sIg isotype of its B cell precursor. Those B cells that have switched to the expression of non-IgM isotypes in vivo can be stimulated in vitro in splenic fragments to give an antibody-secreting clonal culture but so far cannot be stimulated in a microculture of dispersed cells that supports clones secreting IgM alone or with other isotypes.
基于脾片段或微培养中其克隆所表达的CH同种型模式以及培养中支持显示特定同种型或一组同种型的克隆生长所需的那些因素，我们从功能上定义了一些可能代表不同发育阶段B细胞的B细胞亚群。我们的观察结果与同种型转换是一个随机过程相一致，该过程导致多样化克隆成员中逐渐出现同种型限制。最能预测克隆可能分泌的同种型模式的表面标志物是其B细胞前体的sIg同种型。那些在体内已转换为表达非IgM同种型的B细胞，在脾片段中可在体外受到刺激，从而产生分泌抗体的克隆培养物，但迄今为止，在仅支持分泌IgM或与其他同种型一起分泌IgM的克隆的分散细胞微培养中，它们无法受到刺激。
