A method, enzyme-linked immunosorbent assay, was introduced for the determination of antigen-specific immune complex (BSA-anti-BSA) in rabbit circulation. The antigen-specific immune complex in the circulation of twelve rabbits were determined by this method. The results showed that this method accords with the regular pattern of immune complex formation more closely than the antigen-nonspecific assay, PEG precipitation method. The procedure of this method is rather simple, its specificity is of high degree, and the amount of serum needed in test is small. This enzyme-linked immunosorbent assay is a better method to determine the circulating specific immune complex in rabbits.

Experimental acute serum sickness was produced in 20 rabbits By a sensitizing injection with bovine serum albumin (BSA) through the auricular vein. Five days after the sensitization, ten of the 20 animals were given a total body irradiation of 300 r from a 60Co sourse. No radiation was given to the other 10 animals which served as controls. Blood samples were taken from the rabbits of both groups before and 2 , 4 , 6 , 8 , 10, 12, 14, and 16 days after antigen injection. After the sera were seperated, the concentrations of the circulating immune complexes were determined with the PEG complement consumption test. It was found that the dynamic curves of the concentrations of the circulating immune complexes of the two groups were essentially similar. This result strongly suggests that total body irradiation of gamma rays given five days after the sensitization of an antigen exerts no influence on the formation of the circulating immune complexes though acute radiation sickness is well established.