Conrad D H, Lee W T
Int Arch Allergy Appl Immunol. 1985;77(1-2):228-31. doi: 10.1159/000233795.
The murine B lymphocyte receptor for the Fc portion of IgE (Fc epsilon R) was further characterized by using the membrane impermeable cross-linking reagents 3,3'-dithiobis-(sulfosuccinimidyl) proprionate (DTSSP) and bis-(sulfosuccinimidyl) suberate (BS3). IgE could be cross-linked to the Fc epsilon R on the intact cells with either reagent and, in addition, up to 10% of the B cell surface immunoglobulin (sIg; both IgM and IgD) was also found to cross-link to the IgE/Fc epsilon R complex. Analysis of isolated sIg/IgE/Fc epsilon R complexes indicated that about 60% of the Fc epsilon molecules were becoming cross-linked to sIg. Thus, the data suggest that on the intact murine B cell the Fc epsilon R is frequently in close association with sIg. The murine B cell Fc epsilon R was also examined for the presence of receptor-associated proteins that are buried in the membrane. Advantage was taken of the membrane-impermeant nature of DTSSP and BS3. IgE was cross-linked to the Fc epsilon R on intact cells by using the disulfide-cleavable DTSSP and following solubilization with nonionic detergent; BS3 was used to cross-link possible internal membrane components to the Fc epsilon R. In these experiments, the high-affinity Fc epsilon R on rat basophilic leukemia (RBL) cells could be cross-linked to a nonreducible high molecular weight complex of 100 kilodaltons. However, when intact murine B cells were treated with DTSSP, solubilized and treated with BS3 in the same manner as indicated above, no evidence was found for the presence of membrane-buried receptor-associated proteins with the B cell Fc epsilon R. Thus, these data further support the concept that there may be little relationship between the high-affinity mast cell/basophil Fc epsilon R and the low-affinity lymphocyte Fc epsilon R.
通过使用膜不可渗透的交联剂3,3'-二硫代双（磺基琥珀酰亚胺）丙酸酯（DTSSP）和双（磺基琥珀酰亚胺）辛二酸酯（BS3），对小鼠IgE的Fc部分的B淋巴细胞受体（FcεR）进行了进一步表征。两种试剂均可将IgE与完整细胞上的FcεR交联，此外，还发现高达10%的B细胞表面免疫球蛋白（sIg；IgM和IgD）也与IgE/FcεR复合物交联。对分离的sIg/IgE/FcεR复合物的分析表明，约60%的Fcε分子与sIg交联。因此，数据表明在完整的小鼠B细胞上，FcεR经常与sIg紧密结合。还检查了小鼠B细胞FcεR中是否存在埋在膜中的受体相关蛋白。利用了DTSSP和BS3的膜不可渗透性质。通过使用可裂解二硫键的DTSSP将IgE与完整细胞上的FcεR交联，然后用非离子去污剂溶解；使用BS3将可能的内膜成分与FcεR交联。在这些实验中，大鼠嗜碱性白血病（RBL）细胞上的高亲和力FcεR可与100千道尔顿的不可还原高分子量复合物交联。然而，当完整的小鼠B细胞用DTSSP处理、溶解并按上述相同方式用BS3处理时，未发现B细胞FcεR存在埋在膜中的受体相关蛋白的证据。因此，这些数据进一步支持了高亲和力肥大细胞/嗜碱性粒细胞FcεR与低亲和力淋巴细胞FcεR之间可能几乎没有关系的概念。
