RHEUMATOID FACTORS AND CIRCULATING IMMUNE-COMPLEXES IN HYPERIMMUNIZEDRABBITS

Prolonged immunization of rabbits with bovine (BSA) and human (HSA) se rum albumins resulted not only in the production of antigen specific I gG but also in the synthesis of rheumatoid factor (RF)-like autoanti-I gG antibodies in 9 out of 12 animals. RF activity was associated with 19S and 7S fractions of sera. The appearance, duration and disappearan ce of RF correlated with the presence and duration of circulating immu ne complexes (CIC). The immunization period was accompanied by fluctua tions in RF activity and CIC level. This is probably due to the format ion of secondary IC between RF and still existing CIC as was shown by analysis of CIC composition in vitro. The results suggest that RF resp onse in the rabbit may be a composite response based on the contributi ons of both non-specific and specific effects of immune complexes. Hyp erimmunized rabbits were shown to be a useful model for studying the c irculation events concerning the relationship between rheumatoid facto r and immune complexes.