Anti–ro (ss‐a) antibodies from ro (ss‐a)–immunized mice

Abstract

Immunization of BALB/c mice with immuno‐affinity‐purified bovine or human Ro (SS‐A) induces the production of antibodies reactive with Ro (SS‐A). Fusion of spleen cells from the hyperimmunized mice to SP2/0 cells resulted in hybridoma cell lines that produced anti–Ro (SS‐A) antibodies. Anti–Ro (SS‐A) binding was established by solid‐phase immunosorbent assay, immunoblotting, or RNA immunoprecipitation. Most of the anti–Ro (SS‐A) antibodies bound to both human and bovine Ro (SS‐A) in the solid phase, but only one of the monoclonal antibodies selectively bound to human Ro (SS‐A); this suggests that there are species differences between the bovine and human Ro (SS‐A) antigens. Indirect immunofluorescence studies demonstrated that most anti–Ro (SS‐A) antibodies bound to cytoplasmic or nuclear HEp‐2 cellular antigens, whereas others did not bind to fixed HEp‐2 tissue culture cells. Nuclear staining of mouse substrates by one of the sera containing anti–Ro (SS‐A) demonstrated that autoantibodies were induced by immunization with human Ro (SS‐A).