Different elimination of circulating IgA immune complexes in rat and guinea pig. Blood clearance, organ distribution and cellular uptake in the liver.

Soluble IgA immune complexes, formed between 125I-labelled dinitrophenyl-conjugated human serum albumin and mouse IgA anti-dinitrophenyl antibodies (MOPC315), were given intravenously to rats and guinea pigs. Blood clearance kinetics and organ distribution of radioactivity were measured after 15 min. Radioactivity was quantified in isolated parenchymal cells, Kupffer cells (KCs) and liver endothelial cells. IgA complexing did not affect the antigen blood clearance kinetics in either species. In rats, IgA increased the total hepatic antigen uptake, owing to a vast increase in the uptake by parenchymal cells. No IgA-mediated effect could be shown in KCs, still about 40-50% of the hepatic uptake was confined to KCs. In guinea pigs there was also an IgA-mediated increase in hepatic uptake, but here the increase could be ascribed to the KCs alone.