Fate of preformed immune complexes in rabbits and rhesus monkeys

Preformed soluble immune complexes injected into rabbits or rhesus monkeys showed similar characteristics of disappearance from circulation. Complexes made with intact gammaG-antibodies and exceeding the Ag(2)Ab(2) lattice formation were rapidly removed by the hepatic RES. These complexes fixed complement effectively in vitro. Their hepatic uptake was not dependent upon circulating complement components, since their accumulation in the liver was unchanged in complement depleted rabbits. Similar antigen-antibody complexes made with reduced and alkylated gammaG-antibodies fixed complement ineffectively in vitro. These complexes possessed different disappearance characteristics and were not rapidly taken up by the liver, regardless of their degree of lattice formation. Both in vitro and in vivo studies failed to suggest any role for the immune adherence receptor on primate erythrocytes in the handling of circulating soluble immune complexes composed of BSA and gammaG-antibodies to this antigen.