Autologous anti-metatype immune response in rabbits

Rabbits hyperimmunized with fluorescyl-conjugated KLH exhibited bound ligand associated with a high affinity circulating IgG anti-fluorescein population. After cessation of immunogen administration the liganded complexes were eventually spontaneously cleared from the circulation. Individual rabbits synthesized autologous anti-metatype antibodies specific for ligand-antibody complexes. Autologous anti-metatype antibodies reacted optimally with autologous liganded anti-fluorescein antibodies. However, cross reactivity was noted with allogenic rabbit liganded antibodies from three affinity-purified pools. An autologous anti-metatype response, reminiscent of autoanti-idiotype responses, has important implications concerning in vivo clearance of antigen-antibody complexes and may serve as a model to study immune complex diseases.