Effects of Rheumatoid Factor on in vivo Distribution of Aggregated Human IgG and Antigen-Antibody Complexes

Summary

HAggIgG and Tg-antiTg complexes were labelled with I¹³¹ and injected into the peritoneum of rats. These rats were also injected IP with human IgM material, either containing, or free from, RF activity. Animals receiving aggregates plus RF-IgM showed much less radioactivity in the serum, liver, and spleen than controls, 3 hours after injection. Similar findings were noted in the complex-treated animals, except that no difference was noted in serum and evidence was obtained for extensive and rapid thyroglobulin breakdown. In aggregate-treated animals, qualitative differences were also noted in the serum on sucrose gradient centrifugation, suggesting another effect of RF-IgM on aggregate metabolism. Finally it was noted in vitro that extensive RF binding could occur in the Tg-antiTg system, a system which at the same time fixed complement very poorly, if at all.