Catalytic heterogeneity of polyclonal DNA-hydrolyzing antibodies from the sera of patients with multiple sclerosis

Various catalytic antibodies or abzymes have been detected recently in the sera of patients with several autoimmune pathologies, where their presence is most probably associated with autoimmunization. Recently we have shown t hat DNase activity is associated with IgGs from the sera of patients with m ultiple sclerosis (MS) but not with those from the sera of normal humans. H ere we present evidence showing that MS IgC, its F(ab) fragments, and separ ated L-chains catalyze DNA hydrolysis. The properties of the DNase activity of these polyclonal IgGs distinguish them from other known human DNases. I n addition, their specific activities with different oligonucleotide substr ates and the range of optimal pHs, apparent K-M values and substrate specif icities varied widely for different patients. The findings speak in favor o f the generation by the immune systems of individual patients of a variety of polyclonal catalytic IgG pools, from relatively small to extremely large ones. (C) 2001 Elsevier Science B.V. All rights reserved.