Studies in the rat of antibody-coated and <em>N</em>-ethylmaleimide-treated erythrocyte clearance by the spleen II. EFFECTS OF IMMUNE COMPLEX INFUSION.

The effects of immune complex infusion on the clearance of antibody (R3/13)-coated and NEM- treated rat erythrocytes by the splenic component of the rat mononuclear phagocyte system (MPS) were investigated. Equivalence complexes of USA-anti-BSA produced a significant delay in the clearance of the NEM cells (pre-infusion T½ 19.7± 3.9 mm, post-infusion T½ 26.5 ± 3.8 min, mean ± SE, n = 6, P < 0.01), but this effect could be abolished by agents that prevented the changes in the splenic blood flow that followed complement activation. The immune complexes formed in 10- fold antigen excess (mean size 1 5S) did not delay the clearance of the NEM cells. Clearance of R3/13- coated cells was impaired by the infusion of immune complexes prepared at equivalence, 10-fold antigen excess or complexes prepared with F(ab')₂ fragments of rabbit anti-USA antibody. The inhibition of red cell clearance was independent of changes in blood flow, but the degree of inhibition produced did not correlate well with the dose of immune complex injected. [ABSTRACT FROM AUTHOR]