Zhang X H, Werner-Favre C, Tang H Y, Brouwers N, Bonnefoy J Y, Zubler R H
Department of Medicine, Geneva University Hospital, Switzerland.
J Immunol. 1991 Nov 1;147(9):3001-4.
IgE responses by human B cells, separated according to membrane Ig classes, were analyzed in a clonal assay using EL-4 thymoma cells as helper cells, T cell supernatant, and rIL-4. In cultures seeded by means of the autoclone apparatus of the FACS, IgE responses were generated frequently by either IgM (mu+/gamma-alpha-) or IgA (alpha +/mu-)-positive B cells (16 and 14% of the Ig producing wells, respectively), but rarely by IgG (gamma +/mu-)-positive B cells (1.3% of Ig producing wells). The total amounts of Ig secreted by IgM-, IgG-, or IgA-positive cells and the total proportions of responding autoclone wells (23-27%) were comparable. All IgE secretion was IL-4 dependent. When the Ig secretion patterns from alpha +/mu- vs alpha +/mu-epsilon- B cells were compared, most autoclone wells from both types of cells produced IgA only, and similar proportions of IgA producing wells (6.2 and 6.0%) also secreted IgE. In addition, IgE restricted responses occurred 6 times more frequently with alpha +/mu- than with alpha +/mu-epsilon- cells, which suggests that membrane IgA+E double-positive, IgE committed B cells occur in vivo. The isotype pattern generated by alpha +/mu-epsilon- B cells cannot be explained by a chance assortment of separate IgA and IgE precursors or by cytophilic antibody. Thus, IL-4 dependent switch to IgE occurred frequently in IgM- or IgA-positive, but rarely among total IgG-positive, B cells. This could be relevant to IgE production in mucosal tissues rich in IgA expressing B cells.
在一项克隆分析中，使用EL-4胸腺瘤细胞作为辅助细胞、T细胞上清液和重组白细胞介素-4（rIL-4），对根据膜免疫球蛋白（Ig）类别分离的人B细胞的IgE反应进行了分析。在通过荧光激活细胞分选仪（FACS）的自动克隆装置接种的培养物中，IgM（μ⁺/γ-α⁻）或IgA（α⁺/μ⁻）阳性B细胞经常产生IgE反应（分别占产生Ig的孔的16%和14%），但IgG（γ⁺/μ⁻）阳性B细胞很少产生IgE反应（占产生Ig的孔的1.3%）。IgM、IgG或IgA阳性细胞分泌的Ig总量以及反应性自动克隆孔的总比例（23 - 27%）相当。所有IgE分泌均依赖于IL-4。当比较α⁺/μ⁻与α⁺/μ⁻ε⁻ B细胞的Ig分泌模式时，两种类型细胞的大多数自动克隆孔仅产生IgA，并且产生IgA的孔中分泌IgE的比例相似（分别为6.2%和6.0%）。此外，α⁺/μ⁻细胞产生IgE受限反应的频率比α⁺/μ⁻ε⁻细胞高6倍，这表明膜IgA⁺E双阳性、IgE定向的B细胞在体内存在。α⁺/μ⁻ε⁻ B细胞产生的同种型模式不能用单独的IgA和IgE前体的随机组合或亲细胞抗体来解释。因此，依赖IL-4向IgE的转换在IgM或IgA阳性B细胞中频繁发生，但在总IgG阳性B细胞中很少发生。这可能与富含表达IgA的B细胞的黏膜组织中的IgE产生有关。
