von Zabern I, Przyklenk H, Vogt W, Sachsenheimer W
Int J Immunopharmacol. 1983;5(6):503-13. doi: 10.1016/0192-0561(83)90043-7.
Various water soluble iodinated radiographic contrast media (RCM) have been studied for their effect on complement components C3 and C4, purified and in serum. Hepatotropic RCM, and at higher concentration also some nephrotropic RCM, were found to exert a direct effect on purified C3 and C4. RCM treated human C3 and C4 are characterized by (a) loss of haemolytic function, (b) retention of activity in the formation of fluid phase C3 convertases and (c) an antigenic relationship to activated C3 and C4 (C3b and C4b, respectively). This direct alteration of C3 and C4 can probably also occur in serum since loss of haemolytic function is observed at similar RCM concentrations after incubation of serum and of purified components. It is concluded that RCM treated C3 and C4 represent altered forms of these components that resemble C4b and C3b in activity and conformation (C3b-like C3 and C4b-like C4). The alteration is probably caused by binding of RCM, exerting a mild denaturing effect. C3b-like C3 is a potential activator of the alternative pathway, and both C3b-like C3 and C4b-like C4 are known to be cleaved by serum inactivators. A possible pathological significance of the generation of C3b-like C3, C4b-like C4 and their split products remains to be evaluated.
人们已经研究了各种水溶性碘化放射造影剂（RCM）对补体成分C3和C4的影响，这些研究包括纯化状态下以及血清中的情况。亲肝性RCM，以及在较高浓度时的一些亲肾性RCM，被发现对纯化的C3和C4有直接作用。经RCM处理的人C3和C4具有以下特征：（a）溶血功能丧失，（b）在液相C3转化酶形成中保留活性，以及（c）与活化的C3和C4（分别为C3b和C4b）存在抗原关系。C3和C4的这种直接改变在血清中可能也会发生，因为在血清和纯化成分孵育后，在相似的RCM浓度下会观察到溶血功能丧失。得出的结论是，经RCM处理的C3和C4代表了这些成分的改变形式，其活性和构象类似于C4b和C3b（C3b样C3和C4b样C4）。这种改变可能是由RCM的结合引起的，RCM发挥了轻度变性作用。C3b样C3是替代途径的潜在激活剂，并且已知C3b样C3和C4b样C4都会被血清灭活剂裂解。C3b样C3、C4b样C4及其裂解产物产生的可能病理意义仍有待评估。
