Williams G T, Dariavach P, Venkitaraman A R, Gilmore D J, Neuberger M S
Medical Research Council Laboratory of Molecular Biology, Cambridge, U.K.
Mol Immunol. 1993 Nov;30(16):1427-32. doi: 10.1016/0161-5890(93)90104-j.
The canonical form of the B cell antigen receptor is composed of membrane immunoglobulin sheathed by the alpha/beta heterodimer. Whereas membrane IgM cannot be transported to the cell surface in the absence of alpha/beta, both IgD and IgG2b can be expressed naked (i.e. without alpha/beta) on the surface of myeloma transfectants. In the case of one cell-line, such naked IgD has been shown to be inserted into the membrane by a glycosyl-phosphatidylinositol anchor. Here, however, we show that both IgD and IgG2b (but not IgM) can be expressed on the surface of myeloma transfectants without either sheath or anchor. This distinction between the isotypes is attributable to differences in the region of the transmembrane segment.
B细胞抗原受体的标准形式由被α/β异二聚体包裹的膜免疫球蛋白组成。虽然在没有α/β的情况下膜IgM无法转运到细胞表面，但IgD和IgG2b都可以在骨髓瘤转染细胞表面以裸露形式（即没有α/β）表达。在一个细胞系中，这种裸露的IgD已被证明通过糖基磷脂酰肌醇锚定插入膜中。然而，在此我们表明，IgD和IgG2b（但不是IgM）都可以在骨髓瘤转染细胞表面表达，既没有鞘也没有锚定。各同种型之间的这种差异归因于跨膜区段区域的不同。
