CHANGES IN CD45 ISOFORM EXPRESSION ACCOMPANY ANTIGEN-INDUCED MURINE T-CELL ACTIVATION
CHANGES IN CD45 ISOFORM EXPRESSION ACCOMPANY ANTIGEN-INDUCED MURINE T-CELL ACTIVATION
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DOI：
10.1073/pnas.86.17.6734
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发表时间：
1989-09-01
影响因子：
11.1
通讯作者：
PURE, E
中科院分区：
文献类型：
--
作者：
BIRKELAND, ML;JOHNSON, P;PURE, E
白细胞表达一个叫做CD45的质膜蛋白家族或白细胞共同抗原。不同分子量的同工异构体，180- 240kda，是通过选择性剪接和使用三个外显子，命名为A， B和C，编码外部结构域的n端部分产生的。通过使用沉淀B外显子依赖和B外显子独立亚型的单克隆抗体，我们发现小鼠CD4+和CD8+ T细胞在免疫应答期间选择性下调B外显子依赖形式的CD45。这种变化是通过荧光活化细胞分选仪（FACS）分析和表面放射性碘化和代谢标记细胞的免疫沉淀来监测的。在t细胞活化过程中，190 kDa B外显子依赖异构体的丢失伴随着180 kDa形式的增加，该形式不包含B外显子编码序列。这解释了我们的观察结果，即通过FACS分析评估的CD45的总体表达没有变化。
Leukocytes express a family of plasma membrane proteins called CD45 or the leukocyte common antigen. Isoforms of various molecular masses, 180-240 kDa, are produced by alternative splicing and usage of three exons, named A, B, and C, that encode the N-terminal portion of the external domain. By using monoclonal antibodies that precipitate B exon-dependent and B exon-independent isoforms we find that both murine CD4+ and murine CD8+ T cells selectively down-regulate the B exon-dependent forms of CD45 during an immune response. This change was monitored by using fluorescence-activated cell sorter (FACS) analysis and immunoprecipitation from surface radioiodinated and metabolically labeled cells. The loss of the 190 kDa B exon-dependent isoform during T-cell activation is accompanied by an increased production of a 180 kDa form, which does not contain the B exon-encoded sequence. This accounts for our oabservation that the overall expression of CD45, as assessed by FACS analysis, does not change.