O'Brien R M, Kemeny D M
University of Melbourne Department of Medicine, Western Hospital Footscray, Australia.
Scand J Immunol. 1998 Dec;48(6):679-83. doi: 10.1046/j.1365-3083.1998.00460.x.
The expression of different isoforms of the CD45 surface molecule allows lymphocytes to be divided into two nonoverlapping categories, CD45RA and CD45RO. Previous studies of CD4 T cells have shown that responses to soluble antigens are present predominantly in the RO subset and to mitogens in the RA, alloreactivity being present in both subsets. Responses of CD8 T cells have not been investigated in such detail, nor have responses been compared to CD4 cells. Here we report the alloreactive responses of both CD45RA and RO subsets amongst both CD4 and CD8 T lymphocytes. Following isolation of CD4 and CD8 cells with immunomagnetic beads, CD45 subsets were separated by negative depletion using specific monoclonal antibodies. CD45RA populations were greater than 97% pure and CD45RO cells greater than 91%. One-way primary mixed lymphocyte reactions were established using the purified responder cells with irradiated allogeneic peripheral blood mononuclear cells as stimulators; experiments were all repeated at least three times. In assays of CD4+ RA and RO subsets, reactivity was present in both isoforms, being consistently, but not significantly, greater amongst the RO subset. With CD8+ T cells, reactivity was also present in both isoforms, but was significantly greater in the CD45RA subset, with mean proliferation 2.5-3-fold that of the CD45RO cells (P < 0.05).
CD45表面分子不同异构体的表达使得淋巴细胞可分为两个不重叠的类别，即CD45RA和CD45RO。先前对CD4 T细胞的研究表明，对可溶性抗原的反应主要存在于RO亚群中，而对有丝分裂原的反应存在于RA亚群中，同种异体反应性在两个亚群中均存在。CD8 T细胞的反应尚未进行如此详细的研究，其反应也未与CD4细胞进行比较。在此，我们报告了CD4和CD8 T淋巴细胞中CD45RA和RO亚群的同种异体反应。用免疫磁珠分离CD4和CD8细胞后，使用特异性单克隆抗体通过阴性去除法分离CD45亚群。CD45RA群体的纯度大于97%，CD45RO细胞的纯度大于91%。使用纯化的反应细胞与辐照的异体外周血单个核细胞作为刺激物建立单向初级混合淋巴细胞反应；实验均重复至少三次。在CD4+ RA和RO亚群的检测中，两种异构体均有反应性，RO亚群中的反应性始终较高，但差异不显著。对于CD8+ T细胞，两种异构体也都有反应性，但在CD45RA亚群中反应性显著更高，平均增殖是CD45RO细胞的2.5至3倍（P < 0.05）。
