Clearance and localization of immunoglobulin oligomers in mice with chronic circulating endogenous complexes.

The ability of mice with circulating endogenous antigen-antibody complexes to clear and localize heat-aggregated rabbit IgG and a covalently linked tetramer of rabbit IgG anti-IgG was compared with that of normal mice. Although the clearance rates of both probes were unchanged their localization was altered. Hepatic localization in all mice with endogenous complexes was reduced. In some mice, splenic localization was also reduced whereas the amounts in the kidney were increased. These changes could not be attributed to alterations in the blood content of these organs as this was the same as that of normal mice. It is suggested that the observed differences result from saturation of a section of the mononuclear phagocyte system (MPS) with accelerated handling of complexes by mesangial cells in the kidney.