Fujii Y, Okumura M, Inada K, Nakahara K
First Department of Surgery, Osaka University Medical School, Japan.
Cell Immunol. 1992 Jan;139(1):176-84. doi: 10.1016/0008-8749(92)90110-b.
Both CD4+ and CD8+ T cells express either CD45RA or CD45R0 isoform of CD45R in an exclusive way. Recent reports have shown that CD45RA+ T cells lose CD45RA and gain CD45R0 upon activation. This switching has been suggested to be irreversible although more recently, examples of reversal of CD45R isotype switching in CD4+ T cells have been reported. We report here that freshly isolated unprimed CD8+ T cells, when activated with PHA, temporarily lose CD45RA but reexpress an intermediate level of CD45RA 2-3 weeks after activation with PHA. This reversal seems to take place much more slowly in unprimed CD4+ T cells: the majority of CD4+ T cells that had lost CD45RA and gained CD45R0 remained CD45RA-CD45R0+ in 3 weeks after the stimulation. Also, long-term CD8+ CD45RA+ T cell lines stimulated with PHA or OKT3 showed even more rapid recovery of CD45RA while PPD-specific CD4+ T cell clones retained the original CD45R0 phenotype 3 weeks after stimulation with PPD or PHA.
CD4⁺和CD8⁺ T细胞均以排他的方式表达CD45R的CD45RA或CD45R0同种型。最近的报告显示，CD45RA⁺ T细胞在激活后会丢失CD45RA并获得CD45R0。尽管最近有报道称CD4⁺ T细胞中存在CD45R同种型转换逆转的例子，但这种转换被认为是不可逆的。我们在此报告，新鲜分离的未致敏CD8⁺ T细胞在用PHA激活时会暂时丢失CD45RA，但在用PHA激活后2-3周会重新表达中等水平的CD45RA。这种逆转在未致敏的CD4⁺ T细胞中似乎发生得要慢得多：在刺激后3周内，大多数已丢失CD45RA并获得CD45R0的CD4⁺ T细胞仍保持CD45RA⁻CD45R0⁺状态。此外，用PHA或OKT3刺激的长期CD8⁺ CD45RA⁺ T细胞系显示CD45RA的恢复甚至更快，而用PPD或PHA刺激3周后，PPD特异性CD4⁺ T细胞克隆仍保留原始的CD45R0表型。
