Webb Joanna H, Blom Anna M, Dahlbäck Björn
Division of Clinical Chemistry, Department of Laboratory Medicine, Lund University, Sweden.
Blood Coagul Fibrinolysis. 2003 Jun;14(4):355-9. doi: 10.1097/00001721-200306000-00006.
Vitamin K-dependent protein S and complement regulator C4b-binding protein (C4BP) form a high-affinity complex in plasma. We have previously shown that both free protein S and the C4BP-protein S complex can bind to apoptotic Jurkat cells. It has been demonstrated in the past that protein S and C4BP can bind to neutrophils. We now show that it is only the apoptotic neutrophil population that binds these proteins. In addition, we also show that binding is mediated through the Gla domain on protein S, which binds negatively charged phospholipids, since a monoclonal antibody directed against this domain blocks the binding. Thus, we conclude that binding of protein S and the C4BP-protein S complex to neutrophils is not cell specific, but rather apoptosis dependent.
维生素K依赖性蛋白S与补体调节蛋白C4b结合蛋白（C4BP）在血浆中形成高亲和力复合物。我们之前已经表明，游离蛋白S和C4BP-蛋白S复合物都能与凋亡的Jurkat细胞结合。过去已经证明蛋白S和C4BP能与中性粒细胞结合。我们现在表明，只有凋亡的中性粒细胞群体能结合这些蛋白。此外，我们还表明，这种结合是通过蛋白S上结合带负电荷磷脂的Gla结构域介导的，因为针对该结构域的单克隆抗体可阻断这种结合。因此，我们得出结论，蛋白S和C4BP-蛋白S复合物与中性粒细胞的结合并非细胞特异性的，而是依赖于细胞凋亡。
