Purification and identification of antigenic polypeptides of Sm and RNP antigens of goat liver.

A ribonucleoprotein complex containing Sm and RNP antigenic activity was isolated from goat liver. The sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the complex to contain four major polypeptides of 80,000, 70,000, 30,000 and 14,000 molecular weights. When the gels were probed for antigenic polypeptides by an enzyme-linked immunosorbent assay and fluorescent antibody method, anti-Sm sera were found to react with polypeptides of 14,000 and 30,000 molecular weights whereas anti-RNP sera recognized 70,000 and 80,000 molecular weight polypeptides with minor reactivity in the polypeptide of 14,000 molecular weight. Sera containing antibodies to both Sm and RNP reacted with all the four polypeptides.