Comparative studies on antibodies to poly(ADP-ribose) in rabbits and patients with systemic lupus erythematosus

Immunochemical studies were made on the antibodies induced in rabbits against poly(ADP-ribose) and naturally-occurring antibodies in patients with systemic lupus erythematosus. Antibodies against poly(ADP-ribose) could also be induced in rabbits by oligo(ADP-ribose) associated with rat liver histones and by a complex of poly(ADP-ribose) with methylated bovine serum albumin (MBSA). The two types of antibody were inhibited to the same extent by poly(ADP-ribose). However, the antibody induced by oligo(ADP-ribose) associated with histones was inhibited by oligo(ADP-ribose) with an average chain length if 4 ADP-ribosyl units and by phosphoribosyl adenosine monophosphate (PR-AMP) but not by mono ADP-ribose, whereas that induced by poly(ADP-ribose) was practically not inhibited by these related compounds even in excess amounts. The sera of ten cases of systemic lupus erythematosus showing high antibody activity against poly(ADP-ribose) were also examined immunochemically. It was found that the antibodies of three patients showed a similar inhibitory pattern to that of antibody induced in rabbits by oligo(ADP-ribose) associated with histones, those of three patients showed a similar pattern to that of antibody produced in rabbits by poly(ADP-ribose), and the remainder did not show either pattern. These findings suggest that oligo(ADP-ribose) associated with histones may serve as antigen to elicit naturally-occuring antibodies to poly(ADP-ribose) in patients with systemic lupus erythematosus.