Both CD45RA+ and CD45RA- subpopulations of CD8+ T cells contain cells with high levels of lymphocyte function-associated antigen-1 expression, a phenotype of primed T cells.
Both CD45RA+ and CD45RA- subpopulations of CD8+ T cells contain cells with high levels of lymphocyte function-associated antigen-1 expression, a phenotype of primed T cells.
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CD8 T 细胞的 CD45RA 和 CD45RA- 亚群均含有高水平淋巴细胞功能相关抗原 1 表达的细胞，这是引发 T 细胞的一种表型。
作者：
M. Okumura;Y. Fujii;K. Inada;K. Nakahara;H. Matsuda
在T细胞活化过程中，T细胞上的CD 45亚型和一些粘附分子的表达发生变化。在CD 4 + T细胞中，已经报道当CD 4 + T细胞被刺激时，CD 45 RA丢失并且CD 45 RO上调。这种变化似乎是不可逆的，因此CD 45 RA可以作为原始T细胞的标记，CD 45 R 0可以作为CD 4 + T细胞中记忆T细胞的标记。然而，在CD 8 + T细胞中，CD 45同种型的表达还不太清楚。我们以前曾报道过CD 45亚型表达的转换可能是可逆的，并且CD 8 + CD 45 RA + T细胞可能含有预活化的T细胞。我们通过研究人类各种T细胞群体中淋巴细胞功能相关抗原（LFA-1）的表达与CD 45亚型表达的关系，提供了进一步的证据来支持这一观点。在胸腺和脐带血中，超过97%的CD 4+和CD 8+单阳性T细胞低水平表达LFA-1。在CD 4+外周血T细胞中，仅在CD 45 RA-群体中发现高水平的LFA-1表达：98%的CD 45 RA+细胞是LFA-1低。相反，在CD 8+外周血T细胞中，在CD 45 RA+亚群中发现了一个独特的LFA-1high细胞群，在32岁供体中占该亚群的约45%。在PHA刺激后7天，所有的CD 4+和CD 8 + T细胞，无论其CD 45亚型的表达，LFA-1高。刺激后CD 4 + T细胞中CD 45 RA+细胞比例下降，而CD 8 + T细胞中CD 45 RA+细胞比例略有上升。这些结果支持CD 45 RA和CD 45 R 0分别标记CD 4 + T细胞中的原始和记忆T细胞，并且CD 8 + CD 45 RA-T细胞被致敏的观点。然而，CD 45 RA作为CD 8 + T细胞中原始细胞标志物的有效性受到严重质疑。
Expression of CD45 isoforms and some adhesion molecules on T cells change during T cell activation. In CD4+ T cells, it has been reported that CD45RA is lost and CD45RO is up-regulated when CD4+ T cells are stimulated. This change seemed to be irreversible and thus CD45RA may serve as a marker for virgin T cells and CD45R0 as a marker for memory T cells in CD4+ T cells. In CD8+ T cells, however, the expression of CD45 isoform has been less well understood. We have previously reported the switching of CD45 isoform expression may be reversible and CD8+CD45RA+ T cells may contain preactivated T cells. We present further evidence to support this notion by investigating the expression of lymphocyte function-associated Ag (LFA-1) in relation to CD45 isoform expression in various T cell populations in the human. In the thymus and umbilical cord blood, more than 97% of both CD4+ and CD8+ single positive T cells expressed LFA-1 at a low level. In CD4+ peripheral blood T cells, a high level of LFA-1 expression was found only in the CD45RA- population: 98% of CD45RA+ cells were LFA-1low. In CD8+ peripheral blood T cells, in contrast, a distinct population of LFA-1high cells was found in CD45RA+ subset, comprising about 45% of this subset in a 32-yr-old donor. In 7 days after stimulation with PHA, all CD4+ and CD8+ T cells, irrespective of their CD45 isoform expression, were LFA-1high. The proportion of CD45RA+ cells decreased in CD4+ but slightly increased in CD8+ T cells after the stimulation. These results support the notion that CD45RA and CD45R0 mark virgin and memory T cells respectively in the CD4+ T cells, and that CD8+CD45RA- T cells are primed. However, the validity of CD45RA as a marker of virgin cells in CD8+ T cells is seriously questioned.