Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA 02118, USA.
J Immunol. 2011 Jan 15;186(2):1060-7. doi: 10.4049/jimmunol.1002709. Epub 2010 Dec 15.
Human peripheral blood BCRμ(+) B cells express high levels of CD23 and circulate preloaded with IgE. The Ag specificity of CD23-bound IgE presumably differs from the BCR and likely reflects the Ag-specific mix of free serum IgE. CD23-bound IgE is thought to enhance B cell Ag presentation to T cells raising the question of how a B cell might respond when presented with a broad mix of Ags and CD23-bound IgE specificities. We recently reported that an increase in CD23(+) B cells is associated with the development of resistance to schistosomiasis, highlighting the potential importance of CD23-bound IgE in mediating immunity. We sought to determine the relationship between BCR and CD23-bound IgE-mediated B cell activation in the context of schistosomiasis. We found that crude schistosome Ags downregulate basal B cell activation levels in individuals hyperexposed to infectious worms. Schistosome-specific IgE from resistant, occupationally exposed Kenyans recovered responses of B cells to schistosome Ag. Furthermore, cross-linking of CD23 overrode intracellular signals mediated via the BCR, illustrating its critical and dominating role in B cell activation. These results suggest that CD23-bound IgE augments and dominates recall responses through naive B cells.
人外周血 BCRμ(+) B 细胞表达高水平的 CD23，并循环预加载 IgE。CD23 结合的 IgE 的 Ag 特异性可能与 BCR 不同，并且可能反映了游离血清 IgE 的 Ag 特异性混合。CD23 结合的 IgE 被认为增强了 B 细胞向 T 细胞的 Ag 呈递，这就提出了一个问题，即当 B 细胞遇到广泛的 Ag 和 CD23 结合的 IgE 特异性时，它将如何反应。我们最近报道，CD23(+) B 细胞的增加与对血吸虫病的抗性发展有关，突出了 CD23 结合的 IgE 在介导免疫中的潜在重要性。我们试图确定在血吸虫病背景下 BCR 和 CD23 结合的 IgE 介导的 B 细胞激活之间的关系。我们发现，粗制血吸虫 Ag 下调了对感染性蠕虫过度暴露的个体中基础 B 细胞激活水平。来自抵抗性、职业暴露的肯尼亚人的血吸虫特异性 IgE 恢复了 B 细胞对血吸虫 Ag 的反应。此外，CD23 的交联克服了通过 BCR 介导的细胞内信号，说明了它在 B 细胞激活中的关键和主导作用。这些结果表明，CD23 结合的 IgE 通过幼稚 B 细胞增强和主导回忆反应。
