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

Abstract

Aggregated human immunoglobulin G (HAggIgG) and thyro-globulin-antithyroglobulin (Tg-antiTg) complexes were labelled with I131 and injected intraperitoneally (IP) into male Wistar rats. These animals were also injected IP with human IgM, either containing, or free from, rheumatoid factor (RF) activity. Three hours after injection, animals receiving aggregates with RF-IgM showed much less radioactivity in the serum, liver and spleen than animals receiving aggregates with control-IgM. RF-IgM also inhibited absorption of Tg-antiTg complexes from the peritoneum. 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.