Measurement of circulating immune complexes using Fc receptors of guinea pig peritoneal exudate cells. Part 1. Establishment of the method for measuring of immune complexes.

A new method for detecting circulating IgG immune complexes (IC) using guinea pig peritoneal exudate cells (PEC) has been established. Binding of (125)I BSA-anti BSA IgG IC to PEC was inhibited by serum containing IC in a dose dependent fashion. A 100μl aliquot of PEC suspension (2.5X10(6) cells/ml) was preincubated with diluted five fold serum for 60 minutes at 4℃. After washing pretreated PEC 3 times, 100μl of (125)I labelled 3 times antigen excess-IC was added and incubated for 90 minutes at 4℃. At the end of incubation, the suspension was centrifuged at 10,000G for 1 minute, and the radioactivity of the pellet was measured. This method mainly utilizes the reaction between Fc receptors on PEC and the Fc portion of the complexed IgG.