Clissold P M, Ebling H J, Lachmann P J
Molecular Immunopathology Unit, Medical Research Council Centre, Cambridge, GB.
Eur J Immunol. 1993 Sep;23(9):2346-52. doi: 10.1002/eji.1830230944.
By genetic engineering of human CR1 cDNA and its stable transfection into cells we have produced a cell line which expresses CR1 anchored to the cell surface by a glycolipid anchor. The glycosyl-phosphatidylinositol (GPI)-CR1 protects cells intrinsically from damage mediated by complement activated through the classical pathway. Cell surface GPI-CR1 is more efficient on a molar basis than soluble CR1 in the assay, but extrinsic protection of other cells was not obtained. Soluble CR1-protected cells extrinsically in the assay but was required at nearly ten fold higher amounts than the intrinsic protection conferred by GPI-anchored CR1. Additionally, GPI-CR1 was shown to act as a co-factor to Factor I in the generation of C3c from iC3b. Since GPI-anchored proteins can incorporate spontaneously into the membranes of living cells by virtue of their lipid tails, the isolated GPI-CR1 will be used to introduce CR1 on to the surfaces of many different types of cell so that its role in immunity can be further investigated.
通过对人CR1 cDNA进行基因工程改造并将其稳定转染到细胞中，我们构建了一种细胞系，该细胞系表达通过糖脂锚定在细胞表面的CR1。糖基磷脂酰肌醇（GPI）-CR1可从本质上保护细胞免受经典途径激活的补体介导的损伤。在该测定中，基于摩尔比，细胞表面的GPI-CR1比可溶性CR1更有效，但未获得对其他细胞的外在保护。可溶性CR1在该测定中可对细胞起到外在保护作用，但其所需量几乎比GPI锚定的CR1赋予的内在保护高出近十倍。此外，GPI-CR1在从iC3b生成C3c的过程中被证明是I因子的辅助因子。由于GPI锚定蛋白凭借其脂质尾部可自发整合到活细胞的膜中，因此分离出的GPI-CR1将用于将CR1引入多种不同类型细胞的表面，以便进一步研究其在免疫中的作用。
