Doody G M, Justement L B, Delibrias C C, Matthews R J, Lin J, Thomas M L, Fearon D T
Wellcome Trust Immunology Unit, Department of Medicine, University of Cambridge, School of Clinical Medicine, UK.
Science. 1995 Jul 14;269(5221):242-4. doi: 10.1126/science.7618087.
CD22 is a membrane immunoglobulin (mIg)-associated protein of B cells. CD22 is tyrosine-phosphorylated when mIg is ligated. Tyrosine-phosphorylated CD22 binds and activates SHP, a protein tyrosine phosphatase known to negatively regulate signaling through mIg. Ligation of CD22 to prevent its coaggregation with mIg lowers the threshold at which mIg activates the B cell by a factor of 100. In secondary lymphoid organs, CD22 may be sequestered away from mIg through interactions with counterreceptors on T cells. Thus, CD22 is a molecular switch for SHP that may bias mIg signaling to anatomic sites rich in T cells.
CD22是B细胞的一种膜免疫球蛋白（mIg）相关蛋白。当mIg被连接时，CD22会发生酪氨酸磷酸化。酪氨酸磷酸化的CD22结合并激活SHP，SHP是一种已知可通过mIg负向调节信号传导的蛋白酪氨酸磷酸酶。连接CD22以防止其与mIg共聚集，可将mIg激活B细胞的阈值降低100倍。在二级淋巴器官中，CD22可能通过与T细胞上的反受体相互作用而与mIg隔离。因此，CD22是SHP的分子开关，可能会使mIg信号偏向富含T细胞的解剖部位。
