Detection and occurrence of the 60- and 52-kD Ro (SS-A) antigens and of autoantibodies against these proteins.

Abstract

The simultaneous detection of anti-La, anti-60-kD Ro and anti-52-kD Ro antibodies by immunoblotting is greatly improved by changing the crosslinking level in the gel to an acrylamide/bisacrylamide ratio of 19:1. Using this method for the analysis of a number of systemic lupus erythematosus (SLE) and Sjögren's syndrome patient sera it was observed that antibody to the 52-kD Ro protein without anti-60-kD Ro antibody was restricted to Sjögren's syndrome patients (9/26), whereas antibody to the 60-kD Ro protein without contaminating anti-52-kD Ro antibody was only found in SLE patients (8/38). Moreover, in Sjögren's syndrome patient sera anti-Ro antibody was found only in combination with anti-La antibody (20/26), whereas in SLE patient sera anti-Ro antibody could be found without detectable anti-La specificity (4/38). Double immunofluorescence microscopy revealed that the 52-kD Ro and the 60-kD Ro proteins co-localize in the cytoplasm as well as in the nucleus, whereas immunoprecipitation of [32P]-labelled HeLa cell extract with monospecific anti-52-kD Ro and anti-60-kD Ro sera showed that both proteins are associated with the Ro RNAs. These data suggest the presence of both the 52-kD and the 60-kD Ro proteins in the same ribonucleoprotein complexes. To study the evolutionary conservation of the 52-kD Ro, the 60-kD Ro and the La proteins, extracts of cell lines derived from various mammalian species were analysed on Western blots using monospecific human antibodies. In contrast to the 60-kD Ro and the La antigens which are well conserved in evolution, the 52-kD Ro antigen could be detected in primate cells only by this immunological approach.

• Authors: R L Slobbe, G J Pruijn, W G Damen, J W van der Kemp, W J van Venrooij
• Journal: Clinical and experimental immunology (Clin Exp Immunol) Vol. 86 Issue 1 Pg. 99-105 (Oct 1991) ISSN: 0009-9104 [Print] England
• PMID: 1914239 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Autoantibodies
• Autoantigens
• Nuclear Proteins
• RNA, Small Cytoplasmic
• RO60 protein, human
• Ribonucleoproteins
• SS-A antigen
• SS-B antigen

Topics

• Antibody Specificity
• Autoantibodies (analysis)
• Autoantigens (analysis)
• Autoimmune Diseases (immunology)
• Electrophoresis, Polyacrylamide Gel
• Humans
• Molecular Weight
• Nuclear Proteins (immunology)
• RNA, Small Cytoplasmic
• Ribonucleoproteins (immunology)
• Species Specificity
• Tumor Cells, Cultured