Foy T M, Waldschmidt T J
Department of Pathology, University of Iowa College of Medicine, Iowa City 52242.
Eur J Immunol. 1993 Dec;23(12):3208-16. doi: 10.1002/eji.1830231225.
In previous studies, our laboratory demonstrated the utility of the low affinity IgE Fc receptor (Fc epsilon RII) in delineating a number of murine B cell subsets. In the spleen, the Fc epsilon RII is expressed on mature conventional B cells but is absent on marginal zone B cells. In the peritoneal cavity, the receptor is present on all conventional B cells, but is not expressed on fresh peritoneal Ly1/sister B cells. The studies in this report compared the ability of these B cell populations to isotype switch. Using a lipopolysaccharide (LPS)- and interleukin (IL)-4-driven system, sort-purified Fc epsilon RII-positive and -negative B cells from peritoneum and spleen were tested for switching to IgG1, IgE, and IgA. The results demonstrated that regardless of their source, Fc epsilon RII+ B cells produced significant levels of IgG1 and IgE. Similar results were obtained with Fc epsilon RII- (marginal zone) B cells obtained from spleen. In contrast, Fc epsilon RII- (Ly1/sister) peritoneal B cells were found to produce IgG1 and IgA, but were incapable of secreting significant levels of IgE. Further studies tested for LPS and IL-4-induced expression of Fc epsilon RII and Thy1 on the various B cell populations. These experiments demonstrated the induction of the Fc epsilon RII on all B cells, regardless of their initial resting levels. Additionally, Thy1 was found to be induced only on those B cell subsets capable of producing IgE. Taken together, the results demonstrate a correlation between IgE secretion and Thy1 expression, and no apparent correlation between the presence of the Fc epsilon RII and isotype commitment.
在先前的研究中，我们实验室证明了低亲和力IgE Fc受体（FcεRII）在界定多个小鼠B细胞亚群方面的效用。在脾脏中，FcεRII在成熟的传统B细胞上表达，但在边缘区B细胞上不存在。在腹腔中，该受体存在于所有传统B细胞上，但在新鲜的腹腔Ly1/姐妹B细胞上不表达。本报告中的研究比较了这些B细胞群体进行同种型转换的能力。使用脂多糖（LPS）和白细胞介素（IL）-4驱动的系统，对从腹膜和脾脏中分选纯化的FcεRII阳性和阴性B细胞进行向IgG1、IgE和IgA转换的测试。结果表明，无论其来源如何，FcεRII + B细胞都产生了显著水平的IgG1和IgE。从脾脏获得的FcεRII - （边缘区）B细胞也得到了类似的结果。相比之下，发现FcεRII - （Ly1/姐妹）腹腔B细胞产生IgG1和IgA，但不能分泌显著水平的IgE。进一步的研究测试了LPS和IL-4诱导的各种B细胞群体上FcεRII和Thy1的表达。这些实验证明了所有B细胞上FcεRII的诱导，无论其初始静止水平如何。此外，发现Thy1仅在那些能够产生IgE的B细胞亚群上被诱导。综上所述，结果表明IgE分泌与Thy1表达之间存在相关性，而FcεRII的存在与同种型定向之间没有明显的相关性。
