Partial immunochemical characterization of the Ro and La proteins using antibodies from patients with the sicca syndrome and lupus erythematosus.

摘要: Ro and La are intracellular ribonucleoproteins that frequent targets for autoantibodies in the sicca syndrome lupus erythematosus. We analyzed m.w. of protein (antigen) moieties saline cell extracts human spleen by SDS-PAGE immunoblotting, gel filtration, sucrose density ultracentrifugation with radioimmunoassay. pI values proteins were established isoelectric focusing on thin layer agarose gels immunoblotting nitrocellulose transfers. The had an approximately 43 kd was heterogeneous charge, from 4.2 to 4.8. Composite two-dimensional maps developed revealed a characteristic set seven dots kd. determinants identified polypeptides 50 and/or 57 Antigenic activity also detected void volume extract fractionated Sephadex G-200 8 9S greater than 19S regions gradients, suggesting either aggregation or participation protein-protein complexes. 4.3 5.5 obtained antigen, polypeptide similar charge heterogeneity protein, whereas different fingerprint. Immunoblotting bovine, rabbit, dog showed antibodies reacted limited number (m.w. anti-Ro anti-La). These studies support physical independence isolated polypeptides, although precursor product functional relationship vivo is possible. suggest that, addition Western blotting, techniques involving immunodeletion, capillary 2D provide useful approaches characterize saline-soluble cellular antigens.