The examination of antigens in highly purified immune complexes

A combination of gel filtration and affinity chromatography was used for preparation of immune complexes (IC) from sera of individuals with systemic lupus erythematosus (SLE) and others with no apparent disease. Overlaying of gels with patient or normal sera, counterstaining with 125I-protein A and autoradiography showed besides immunoglobulins, the presence of 6 unidentified antigens with molecular weights below 42,000 dalton. They were not exclusively associated with SLE IC.