Clearance of circulating DNA-anti-DNA immune complexes in mice

DNA-anti-DNA immune complexes, produced from single-stranded DNA and IgG from a patient with systemic lupus erythematosus were cleared from the circulation of normal mice extremely rapidly, at a rate similar to the clearance of DNA alone. The initial clearance of these complexes was more rapid than the clearance of aggregated IgG, a surrogate immune complex containing a comparable number of IgG molecules, suggesting that the antigen (DNA) in the complexes significantly altered the clearance kinetics of the complexes. Analysis of the late clearance component of these complexes showed that anti-DNA is released back into the circulation after initial removal, and is then cleared at a rate similar to monomeric IgG. Whether this anti-DNA represents free antibody, or antibody bound to small nuclease digested DNA fragments, awaits further study.