Strober W, Harriman G R, Kunimoto D R
Mucosal Immunity Section, LCI, National Institute of Allergy and Infectious Diseases, Bethesda, Md.
Immunol Res. 1991;10(3-4):386-8. doi: 10.1007/BF02919726.
The overall picture of IgA B cell differentiation to emerge from these studies is that sIgM-bearing 'virgin' B cells entering the Peyer's patches are subject to a microenvironment (most probably organ-specific stromal cells) which brings about initial or primary IgA switch differentiation. For reasons mentioned, this probably does not involve TGF-beta, which instead appears to operate on a cell, such as the CH12.LX B cell, which has already undergone the initial steps of IgA isotype switching. The next stage of IgA B cell differentiation involves a cell which expressed both sIgM and sIgA simultaneously and appears to produce C mu and C alpha mRNA transcripts in the absence of a deletional rearrangement. Whether this involves a 'transplicing' mechanism or some other mechanism has yet to be determined. Finally, committed IgA B cells emerge from the dual-bearing cell population which express only sIgA. These cells can migrate out of Peyer's patches and respond to various terminal differentiation factors such as IL-5, IL-6 and IFN-gamma.
从这些研究中得出的关于IgA B细胞分化的总体情况是，进入派氏结的携带sIgM的“原始”B细胞会受到一种微环境（很可能是器官特异性基质细胞）的影响，这种微环境会引发初始或初级IgA类别转换分化。由于上述原因，这可能不涉及TGF-β，相反，TGF-β似乎作用于已经经历了IgA同种型转换初始步骤的细胞，如CH12.LX B细胞。IgA B细胞分化的下一阶段涉及一种同时表达sIgM和sIgA的细胞，并且在没有缺失重排的情况下似乎产生Cμ和Cα mRNA转录本。这是否涉及“转拼”机制或其他机制还有待确定。最后，成熟的IgA B细胞从仅表达sIgA的双表达细胞群体中产生。这些细胞可以从派氏结迁移出来，并对各种终末分化因子如IL-5、IL-6和IFN-γ作出反应。
