Concerning the Mechanism of Complement Action

[摘要] In confirmation of previous work it has been found that C′1 can bind to the sensitized red cell in an hemolytically active form in the absence of the other components. The attachment of C′1 and its subsequent removal leaves a sensitized cell which does not differ from a cell which never had been in contact with C′1 in its susceptibility to hemolysis by whole complement or in its ability to again bind C′1.The attachment of C′1 is necessary for the binding of C′4 activity, however, C′1 can then be removed and the cell will still retain C′4 activity. The presence of both C′1 and C′4 activity is required for the uptake of C′2 activity. However, once C′2 activity is attached C′1 is no longer required; its function has been performed. C′1 can be removed and the cell will still be able to lyse in the presence of C′3 as long as C′2 activity remains on the cell.These facts lead to the view that with regard to immune hemolysis C′1 does nothing more to the sensitized cell than attach itself. Once on the cell C′1 acts upon C′4 and C′2 preparing and allowing their activities to bind to the sensitized cell. C′1 on the cell inactivated by diisopropyl-fluorophosphonate (DFP) is no longer capable of binding C′4 or C′2. This leads to the inference that it is the enzymatic action of C′1 on C′4 and C′2 which leads to their being bound. C′1 does not play a role in the decay of C′2 on the cell.

[学科分类] 生物科学（综合）