Shared idiotypes on anti-DNA and anti-poly (ADP-ribose) antibodies

Hed 10 is a ssDNA-specific mAb derived from an NZB/W autoimmune mouse. ADP 1 is a poly(ADP-ribose)-specific mAb derived from a C57BL/6 mouse. Rabbit anti-idiotypic sera were raised against Hed 10 and ADP 1. By affinity chromatography it was shown that at least 20 to 30% of DNA-binding antibodies contained these idiotypes. The sera were also used to evaluate idiotypic cross-reactivity among 26 diverse, predominantly anti-nucleic acid, murine mAb. Each serum bound directly to several mAb and in addition inhibited the binding of several antibodies to their appropriate Ag. The anti-Hed 10 serum detected an idiotype which was restricted to antibodies that bound to poly(dT) and/or poly(ADP-ribose). The anti-ADP 1 serum detected a more widely distributed idiotype contained in antibodies which bound to a variety of nucleic acids. Although both sera bound directly to Hed 10, only the anti-Hed 10 serum could compete for the binding of Hed 10 to poly(dT). On the other hand, both sera could compete for the binding of ADP 1 to poly(ADP-ribose) as well as bind directly to ADP 1. In addition anti-ADP 1 serum appeared to enhance, rather than inhibit, the binding of one mAb to native calf thymus DNA and polyd(AT)] but had no effect on the binding to several ssDNA. These results demonstrate that many antibodies which recognize DNA and poly(ADP-ribose) have shared idiotypes. This may be of relevance to the development of autoimmunity because poly(ADP-ribose) is ubiquitous and immunogenic.