Isolation of soluble immune complexes from human serum: combined use of polyethylene glycol precipitation, gel filtration, and affinity chromatography on protein A-Sepharose.

摘要: Publisher Summary This chapter discusses the isolation of soluble immune complexes (IC) from human serum, with combined use polyethylene glycol (PEG) precipitation, gel filtration, and affinity chromatography on protein. The most popular approach to ICs has been immobilized staphylococcal protein A as a substrate. PEG is known precipitate antigen-antibody more readily than free antigen or antibody. It found that at concentration used for first step, IgM, IgG, a2-macroglobulin, C4 are also precipitated even in their native forms. Additional steps needed separate these proteins. Gel filtration any several types can be effectively high molecular-weight fractions monomeric IgG. Double immunodiffusion analysis showed pool III contained IgG only, indicating this patient had mixture atypical anti-immunoglobulin antibodies, probably including IgM anti-IgA anti-IgG. results formed vitro indicate sepharose G-50, under dissociating conditions, an effective dissociation insulin-anti-insulin IC.