Relationship of Circulating Antigen-Antibody Complexes, Antigen Elimination, and Complement Fixation in Serum Sickness.

Abstract

Neither the level of antigen-agtibody complexes in the serum nor amount of complement utilized during the responses of rabbits to large injections of BSA could be correlated consistently with either the development or severity of the lesions of serum sickness. Almost all rabbits responded to large injections of BSA by making antibodies capable of forming complexes with circulating antigen yet only 2/3 of them developed significant lesions. On the whole those animals making the earliest responses and eliminating the complexes most rapidly had the most severe lesions; but some animals in which complexes were not eliminated rapidly from the blood also developed lesions. Likewise complement did not appear to be utilized in some rabbits which developed lesions and in some rabbits showing a fall in complement no lesions were found. Thus, it would appear that either there are other factors in addition to complexes and complement which are essential in the pathogenesis of serum sickness or that the complexes vary in their properties from animal to animal and that some of these complexes are more pathogenic than others.