Interaction of complement solubilized complexes with mouse peritoneal macrophages and their clearance and tissue uptake.

To clarify the biological activity of complement solubilized immune complexes, we studied their interaction with mouse peritoneal macrophages. The solubilized complexes lost their binding affinity for C3b receptor and Fc receptor but still bound to MPM mainly via the C3bi receptor (CR3). When solubilized immune complexes were injected into mice, they were more rapidly removed from the circulation than antigen excess soluble complexes and taken up by the liver Kupffer cells. Therefore, the solubilized complexes could be catabolized by the reticuloendothelial system, mainly in the liver. Probably, CR3 plays an important role in this process.