Heterogeneity of anti-dsDNA antibodies in their cross-reaction with ribosomal P protein

We have investigated the possible cross-reaction of anti-dsDNA antibodies w ith ribosomal P peptide for several reasons. First, the antibodies frequent ly occur together, and secondly, they vary similarly with disease activity. Human polyclonal anti-dsDNA antibodies were affinity purified from eight p atients and anti-ribosomal P antibodies from two patients with systemic Lup us erythematosus (SLE) who had high titers of anti-dsDNA as well as anti-ri bosomal P antibodies. Nine of the 10 sera were totally specific in their re activity with their cognate antigens. in only one patient did we find a sub population of antibodies which cross-reacted with both dsDNA and the carbox yl terminal 22 amino acid peptide. Our results indicate that anti-dsDNA ant ibodies are heterogeneous and usually do not cross-react with the carboxyl terminal P peptide, but on occasion (1/10) a patient will produce anti-dsDN A antibodies cross-reactive with the carboxyl terminal P peptide. (C) 1999 Academic Press.