[Molecular cloning, expression and epitope mapping of nuclear antigen]

The antinuclear antibody is a major characteristic phenomenon in systemic type of autoimmune diseases. There is a good correlation between symptoms or diseases and the types of antinuclear antibodies in these patients. Therefore, the study of the mechanisms of antinuclear antibody production is thought to be important in the elucidation of the pathogenesis of such autoimmune diseases. The conventional methods to detect antinuclear antibodies have been useful to date in clinical studies. However, these methods are not sufficient for more precise investigations. Thus, we have applied the recently developed molecular biology to this field. cDNAs which encode nuclear antigens have been cloned and their protein products were expressed as recombinant fusion protein in E. coli. By this procedure, we could establish simple and reproducible method to detects antinuclear antibodies. Furthermore, epitope mapping of nuclear antigens could be performed using deletion mutants generated by enzymatic manipulations of the cDNAs. These epitope studies are facilitating a more precise understanding of the mechanisms of antinuclear antibody production.