Rosenspire A J, Lee M S, Pollak S V, Choi Y S
Mol Immunol. 1986 Jan;23(1):1-13. doi: 10.1016/0161-5890(86)90166-5.
Membrane immunoglobulin receptors on chicken B-cells have been shown to display a heterogeneity with respect to interchain disulfide linkages. One fraction of the surface Ig (sIg) appears to display the traditional H2-L2 linkage. We also present evidence that this Ig is covalently bound via a disulfide linkage to actin. In this instance, the isolated Ig heavy chain, after reduction, has a mol. wt of 80 K. Perhaps more significantly, we show that another fraction of the sIg exists in a highly aggregated from that is stabilized by disulfide linkages. In contrast to the sIg found in the H2-L2 configuration, there is no evidence of actin within the aggregates and the sIg heavy chains isolated from these aggregates display a slightly faster mobility on SDS-PAGE under reducing conditions, running at about 77K. Furthermore, it appears that the Ig within the large aggregates may have a higher avidity with respect to antigen binding, and so this Ig structure may be the more relevant to antigen-induced receptor-mediated signaling in the B-cell.
鸡B细胞上的膜免疫球蛋白受体已被证明在链间二硫键连接方面表现出异质性。一部分表面免疫球蛋白（sIg）似乎呈现传统的H2-L2连接。我们还提供证据表明，这种免疫球蛋白通过二硫键与肌动蛋白共价结合。在这种情况下，还原后的分离免疫球蛋白重链的分子量为80K。也许更重要的是，我们表明另一部分sIg以高度聚集的形式存在，这种聚集通过二硫键得以稳定。与以H2-L2构型存在的sIg不同，在聚集体中没有肌动蛋白的证据，并且从这些聚集体中分离出的sIg重链在还原条件下的SDS-PAGE上迁移速度稍快，约为77K。此外，大聚集体中的免疫球蛋白似乎对抗原结合具有更高的亲和力，因此这种免疫球蛋白结构可能与B细胞中抗原诱导的受体介导信号传导更为相关。
