Studies of reticuloendothelial function in the mouse with model immune complexes. I. Serum clearance and tissue uptake in normal C3H mice

The authors have used stable immune complexes site-specifically cross-linked by way of their combining sites to characterize the elimination of immune complexes in the mouse. These complexes, prepared from rabbit or mouse anti-DNP IgG antibodies, were separated into relatively homogeneous preparations of monomers, dimers, and heavy oligomers. The authors found that oligomers consisting of rabbit antibodies were cleared from the serum at rates similar to oligomers of homologous mouse antibody. Serum clearance of dimeric immunoglobulin was indistinguishable from clearance of monomer, but dimer accumulated in the liver at least 3 times faster than monomer. In addition, dimer, like heavy oligomer, bound to circulating blood cells whereas monomer did not. Heavy oligomers were removed from the serum initially at rates about 3-fold that of monomer, principally by the liver. Eighty per cent of heavy oligomers were located within the liver at 1 hr, with less than 1% in the spleen, kidneys, or lungs. Recovery data suggest that oligomers that remain primarily within the intravascular space before liver uptake were removed considerably more rapidly than those oligomers diffusing into the interstitial space.