• 1 January 1979
    • journal article
    • research article
    • Vol. 37  (2) , 295-309
Abstract
A procedure for the isolation of immune complexes from human serum was developed. Two steps are involved: lipid-free serum is precipitated by polyethylene glycol; the solubilized precipitate is absorbed on a column of polymethylmethacrylate beads coated with conglutinin (K) or C1q [q fragment of complement component 1]; the column is washed, the complexes are then eluted, using 0.02 M EDTA (for K column) or 0.5 M NaCl (for C1q column). This procedure permitted the purification and the characterization of soluble 125I-BSA[bovine serum albumin]-anti-BSA, 125I-tetanus toxoid-anti-tetanus toxoid, and 125I-HBsAg-anti-HBsAg complexes made in vitro in the presence of fresh human serum. The isolated complexes contained antigen, antibody, C1q, C1r, C1s and C3. When normal human serum was submitted to such a procedure, no detectable amount of protein was present in the final eluted fraction. Immune complexes formed in vivo were also purified by conglutinin column from the serum of a patient with disseminated leishmaniasis. The isolated material contained IgM, IgG, C1q, C1r, C1s, C3c and C3d. The purified complexes dissociated at acid pH contained anti-IgG and anti-leishmania antibodies.