Abstract
Immunization of animals with DNA leads to the production of anti‐DNA antibodies (Abs) demonstrating both DNase and RNase activities. It is currently not known whether anti‐RNA Abs can possess nuclease activities. In an attempt to address this question, we have shown that immunization of three rabbits with complex of RNA with methylated BSA (mBSA) stimulates production of IgGs with RNase and DNase activities belonging to IgGs, while polyclonal Abs from three non‐immunized rabbits and three animals immunized with mBSA are catalytically inactive. Affinity chromatography of IgGs from the sera of autoimmune (AI) patients on DNA‐cellulose usually demonstrates a number of fractions, all of which effectively hydrolyze both DNA and RNA, while rabbit catalytic IgGs were separated into Ab subfractions, some of which demonstrated only DNase activity, while others hydrolyzed RNA faster than DNA. The enzymic properties of the RNase and DNase IgGs from rabbits immunized with RNA distinguish them from all known canonical RNases and DNases and DNA‐ and RNA‐hydrolyzing abzymes (Abzs) from patients with different AI diseases. In contrast to RNases and AI RNA‐hydrolyzing Abs, rabbit RNase IgGs catalyze only the first step of the hydrolysis reaction but cannot hydrolyze the formed terminal 2′,3′‐cyclophosphate. The data indicate that Abzs of AI patients hydrolyzing nucleic acids in part may be Abs against RNA and its complexes with proteins. Copyright © 2008 John Wiley & Sons, Ltd.