Millet I, Briere F, Vincent C, Rousset F, Andreoni C, De Vries J E, Revillard J P
Laboratory of Immunology--INSERM U80 CNRS UA 1177 UCBL Hôpital E. Herriot, Lyon, France.
Clin Exp Immunol. 1989 May;76(2):268-73.
Expression of receptors for IgA (Fc alpha Rs) was investigated on a panel of 35 human B cell lines by labelling with human secretory IgA (0.5 mg/ml) and flow cytometry analysis after staining with fluoresceinated goat anti-human secretory component and/or anti-alpha chain F(ab')2 fragments. Receptors for IgA could be demonstrated on one out of nine Burkitt's lymphoma cell lines, three out of five myeloma cell lines and five out of 21 lymphoblastoid cell lines. The percentage of Fc alpha R-positive cells within the same B cell line varied upon repeated examination. Human dimeric IgA1 lambda myeloma protein revealed the same number of IgA receptor positive cells as did secretory IgA, whereas monomeric IgA did not bind to Fc alpha R. Detection of Fc alpha R was not inhibited when the tests were carried out in the presence of human dimeric IgG, IgM, asialo-orosomucoid, and secretory component but it was abrogated by pre-treatment of the cells with trypsin. The binding characteristics of Fc alpha Rs were studied on the myeloma cell line Esteve, using 125I-labelled human dimeric IgA and secretory IgA. The binding was dose-dependent with rapid kinetics and specific inhibition by unlabelled secretory IgA. Scatchard plot analysis resulted in an equilibrium constant K ranging from 3.2 to 4.7 x 10(6) M/l. No correlation was observed between Fc alpha R expression and differentiation stage, monoclonality, polyclonality of the cell lines, or Ig class produced by the B cells.
通过用人类分泌型IgA（0.5mg/ml）标记，并在用荧光素标记的山羊抗人类分泌成分和/或抗α链F(ab')2片段染色后进行流式细胞术分析，在一组35个人类B细胞系中研究了IgA受体（FcαRs）的表达。在9个伯基特淋巴瘤细胞系中的1个、5个骨髓瘤细胞系中的3个以及21个淋巴母细胞系中的5个中可检测到IgA受体。同一B细胞系中FcαR阳性细胞的百分比在重复检测时有所变化。人二聚体IgA1λ骨髓瘤蛋白显示出与分泌型IgA相同数量的IgA受体阳性细胞，而单体IgA不与FcαR结合。当在人二聚体IgG、IgM、去唾液酸血清类黏蛋白和分泌成分存在的情况下进行检测时，FcαR的检测未受抑制，但细胞用胰蛋白酶预处理后则被消除。使用125I标记的人二聚体IgA和分泌型IgA，在骨髓瘤细胞系Esteve上研究了FcαRs的结合特性。结合呈剂量依赖性，动力学快速，且可被未标记的分泌型IgA特异性抑制。Scatchard图分析得出平衡常数K范围为3.2至4.7×10(6)M/l。未观察到FcαR表达与细胞系的分化阶段、单克隆性、多克隆性或B细胞产生的Ig类别之间存在相关性。
