Parkhouse R M
National Institute for Medical Research, Mill Hill, London.
Immunology. 1990 Feb;69(2):298-302.
Three cell-surface molecules associated with surface Ig on murine B cells have been identified. Surface-iodinated resting B cells were lysed in digitonin or Nonidet P-40. The lysates were then examined by immunocoprecipitation with anti-Ig reagents and SDS-PAGE. By this procedure, a 73,000 MW heterodimer, composed of 35,000 and 38,000 MW disulphide-linked subunits, was found to be associated with both mIgM and mIgD. This association was detectable in the detergent digitonin, but not Nonidet P-40. As an alternative approach, resting B cell mIg was capped and internalized by anti-Ig induced mIg cross-linking. The resulting 'modulated' cells were then screened for surface reactivity with a panel of monoclonal antibodies. Most antibodies tested (anti-class I, -class II, -LFA, -FcR gamma, -FcR epsilon) reacted equally well with control and modulated B cells. With two, however, there was a significant reduction in surface representation on modulated B cells. One determinant corresponds to a previously undescribed 90,000 MW murine surface marker, and the other was a polydisperse glycoprotein recognized by the mAb J11D.
已鉴定出与鼠B细胞表面免疫球蛋白（Ig）相关的三种细胞表面分子。用洋地黄皂苷或Nonidet P - 40裂解经表面碘化的静止B细胞。然后用抗Ig试剂和SDS - PAGE通过免疫沉淀法检查裂解物。通过该程序，发现由35,000和38,000分子量的二硫键连接亚基组成的73,000分子量异二聚体与mIgM和mIgD均相关。这种关联在去污剂洋地黄皂苷中可检测到，但在Nonidet P - 40中未检测到。作为另一种方法，静止B细胞mIg通过抗Ig诱导的mIg交联进行封帽和内化。然后用一组单克隆抗体筛选产生的“调节”细胞的表面反应性。测试的大多数抗体（抗I类、抗II类、抗淋巴细胞功能相关抗原（LFA）、抗FcRγ、抗FcRε）与对照B细胞和调节B细胞的反应同样良好。然而，对于两种抗体，调节B细胞表面的表达显著降低。一种决定簇对应于一种先前未描述的90,000分子量的鼠表面标志物，另一种是被单克隆抗体J11D识别的多分散糖蛋白。
