Hanna S Melanie, Spiller O Brad, Linton Stuart M, Mead Richard J, Morgan B Paul
Complement Biology Group, Department of Medical Biochemistry, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XX, Wales, GB.
Eur J Immunol. 2002 Feb;32(2):502-9. doi: 10.1002/1521-4141(200202)32:2<502::AID-IMMU502>3.0.CO;2-0.
All human blood cells express decay-accelerating factor (DAF, CD55), CD59, and, with the exception of erythrocytes, membrane cofactor protein (MCP, CD46) to protect themselves from damage by the constant low-level activation of complement in serum. In rats and mice MCP is expressed only in testis, whereas DAF and CD59 are broadly distributed. Rats and mice also express a unique complement regulator, Crry. Previously we have shown that DAF was absent from at least 75% of rat T cells. To further investigate this surprising finding, we assessed the expression levels of DAF, CD59 and Crry on all blood cell types in the rat. We found that Crry was abundantly expressed on all blood cells. CD59 was expressed abundantly on erythrocytes and granulocytes but was absent from all T cellsand platelets and a minority of B cells and NK cells. Double staining and depletion studies showed that T cells in all rat strains tested were DAF-CD59-. Neutralization of Crry using a blocking monoclonal antibody rendered T cells susceptible to lysis by homologous complement, indicating that Crry was solely responsible for protecting DAF-CD59- T cells from complement damage in the rat.
所有人类血细胞都表达衰变加速因子（DAF，CD55）、CD59，除红细胞外，还表达膜辅因子蛋白（MCP，CD46），以保护自身免受血清中补体持续低水平激活所造成的损伤。在大鼠和小鼠中，MCP仅在睾丸中表达，而DAF和CD59分布广泛。大鼠和小鼠还表达一种独特的补体调节蛋白Crry。此前我们已表明，至少75%的大鼠T细胞中不存在DAF。为进一步研究这一惊人发现，我们评估了大鼠所有血细胞类型上DAF、CD59和Crry的表达水平。我们发现Crry在所有血细胞上大量表达。CD59在红细胞和粒细胞上大量表达，但在所有T细胞、血小板以及少数B细胞和NK细胞中不存在。双重染色和去除研究表明，所测试的所有大鼠品系中的T细胞均为DAF - CD59阴性。使用阻断性单克隆抗体中和Crry会使T细胞易被同源补体裂解，这表明在大鼠中Crry是保护DAF - CD59阴性T细胞免受补体损伤的唯一因素。
