Dianzani U, Luqman M, Rojo J, Yagi J, Baron J L, Woods A, Janeway C A, Bottomly K
Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06510.
Eur J Immunol. 1990 Oct;20(10):2249-57. doi: 10.1002/eji.1830201014.
Different isoforms of CD45 are expressed on naive and memory CD4 T cells in the mouse, as revealed by an antibody to a set of isoforms of CD45 that utilize exon B, called CD45RB. Cloned TH1 and TH2 lines also differ for expression of isoforms detected by this antibody. Differential expression of CD45 isoforms correlates with different behavior of cell surface molecules involved in transmembrane signal transduction. On naive T cells, CD4, CD45 and the CD3/T cell receptor complex behave as independent entities. On memory T cells, these three molecules are stably associated on the T cell surface. Furthermore, on TH2 cells, which express intermediate levels of CD45RB, CD4 is stably associated with CD45 isoforms other than CD45RB, but this complex is not associated with the CD3/T cell receptor. These results lead us to propose that immunological memory in CD4 T cells consists of an altered structure of the T cell's specific signal transduction apparatus controlled by low-molecular weight CD45 isoforms. This altered receptor structure would allow the more sensitive triggering of the T cell characteristic of memory cells. The organization of multimolecular signal transduction systems may be a general means by which cells alter their physiological behavior, allowing the acquisition of new phenotypic characteristics.
正如一种针对一组利用外显子B的CD45异构体（称为CD45RB）的抗体所揭示的那样，小鼠的初始和记忆CD4 T细胞上表达不同的CD45异构体。克隆的TH1和TH2细胞系在这种抗体检测到的异构体表达上也存在差异。CD45异构体的差异表达与跨膜信号转导中涉及的细胞表面分子的不同行为相关。在初始T细胞上，CD4、CD45和CD3/T细胞受体复合物表现为独立的实体。在记忆T细胞上，这三种分子在T细胞表面稳定结合。此外，在表达中等水平CD45RB的TH2细胞上，CD4与除CD45RB之外的CD45异构体稳定结合，但这种复合物不与CD3/T细胞受体结合。这些结果使我们提出，CD4 T细胞中的免疫记忆由低分子量CD45异构体控制的T细胞特异性信号转导装置的结构改变组成。这种改变的受体结构将允许更敏感地触发记忆细胞特有的T细胞。多分子信号转导系统的组织可能是细胞改变其生理行为、获得新表型特征的一种普遍方式。
