Immunization with short peptides from the sequence of the systemic lupus erythematosus-associated 60-kDa Ro autoantigen results in anti-Ro ribonucleoprotein autoimmunity

Systemic lupus erythematosus is characterized by the production of Abs to ribonucleoproteins, including Ro (or SS-A) and La (or SS-B). The mechanism by which these autoantibodies arise is unknown. We have immunized rabbits with peptides from the sequence of the 60-kDa Ro. Animals so immunized not only produce Abs to the immunogen peptide, but also develop an autoimmune response to the entire 60-kDa Ro Ag. In about 20% of these animals, autoimmunity also spreads to the La Ag. Anti-native DNA was present in one of nine rabbits. All animals had anti-nuclear Ab, but even among those immunized with the same peptides, different patterns of immunofluorescence were found. Thus, among these outbred animals immunized with peptides from 60-kDa Ro, distinct serologic manifestations were present, showing heterogeneity in the development of autoimmunity.