Trautmann M, Triest K, Hofstaetter T, Seiler F R, Hahn H
Zentralbl Bakteriol Mikrobiol Hyg A. 1985 Feb;259(1):104-17. doi: 10.1016/s0176-6724(85)80012-2.
Commercially available immunoglobulin products suitable for intravenous application in humans are made by enzymatic or chemical modification of the IgG molecule. In order to examine, to which extent in vitro biologic functions of the IgG molecule are preserved in such preparations, specific antipseudomonal IgG from the rabbit was modified according to some of these procedures. The opsonizing activity of the different IgG preparations was evaluated in an in vitro system measuring the phagocytosis of Pseudomonas aeruginosa by rabbit granulocytes. The results demonstrated that the product Fab/Fc, which is made by papain or plasmin degradation of the IgG molecule, was still able to enhance phagocytosis but not to activate complement. The smaller papain- or plasmin-derived fragments Fab and Fc had no opsonizing activity. The pepsin-derived product F(ab')2 which possesses a divalent antigen binding site but lacks the Fc part, only enhanced phagocytosis when complement concentrations of more than 20% were present in the phagocytic system. Since the F(ab')2 fragment is not able to interact with Fc receptors or to activate complement via the classical pathway, the phagocytosis-enhancing activity of this molecule must be attributed to alternative complement pathway activation. In contrast to the enzymatically derived IgG preparations, a newly developed S-sulphonated IgG product was as efficient as unmodified IgG both in Fc- and complement-mediated opsonization.
适用于人类静脉注射的市售免疫球蛋白产品是通过对IgG分子进行酶促或化学修饰制成的。为了研究在这些制剂中IgG分子的体外生物学功能在多大程度上得以保留，按照其中一些方法对来自兔子的特异性抗铜绿假单胞菌IgG进行了修饰。在一个测量兔粒细胞对铜绿假单胞菌吞噬作用的体外系统中评估了不同IgG制剂的调理活性。结果表明，通过木瓜蛋白酶或纤溶酶降解IgG分子制成的Fab/Fc产物仍能够增强吞噬作用，但不能激活补体。较小的木瓜蛋白酶或纤溶酶衍生片段Fab和Fc没有调理活性。胃蛋白酶衍生产物F(ab')2具有二价抗原结合位点但缺乏Fc部分，只有当吞噬系统中补体浓度超过20%时才增强吞噬作用。由于F(ab')2片段不能与Fc受体相互作用或通过经典途径激活补体，该分子的吞噬增强活性必定归因于替代补体途径的激活。与酶促衍生的IgG制剂相反，一种新开发的S-磺化IgG产品在Fc介导和补体介导的调理作用方面与未修饰的IgG一样有效。
