BACKGROUNDPatients with systemic lupus erythematosus often have various autoantibodies. The relationship between these antibodies is still poorly understood. The aim of the present study was to observe the anti-SSB antibody and anti-dsDNA antibody production profiles following immunization with synthetic SSB peptide alone, DNA alone or co-immunization with these two antigens.

METHODSSSB 214 - 225 aa peptide was synthesized by organic chemistry solid-phase peptide synthesis. Rabbits were immunized with the following antigens: synthetic SSB peptide linked with keyhole limpet hemocyanin (KLH), DNA, SSB plus dsDNA, KLH and PBS. Antibodies were measured by ELISA. Histopathology and direct immufluorescence assays were also applied.

RESULTSAnti-SSB and anti-dsDNA antibodies were produced following immunization with SSB peptide and DNA respectively. The level of SSB antibody in the co-immunization group was higher than that of the SSB peptide immunization group. The level of anti-dsDNA antibody in the co-immunization group was, however, lower than that in the DNA immunization group. Meanwhile, the level of anti-SSB antibody was higher than that of anti-DNA antibody in the co-immunization group. No morphological or immunological abnormalities were found in the heart, liver, kidney, spleen or skin tissues.

CONCLUSIONInhibition of anti-dsDNA-antibody was induced by co-immunization with synthesized SSB peptide and DNA, which might explain, at least partly, the mild disease in some LE subsets associated with SSB antibody.