cDNA cloning of small nuclear and cytoplasmic RNA-associated proteins.

cDNA cloning has been a highly successful tool in elucidating the structure of U- and Y-RNA associated proteins. Whereas sera from autoimmune patients have often been helpful in the procedure, the cloning has not yet elucidated why such patients recognize especially these nuclear antigens. The finding of a repetitive proline-rich epitope in A/B/B'/N/C is interesting with regard to the findings of Gleichmann et al. (48,49), who studied an SLE-like disease in Graft-versus-Host diseased mice. It was shown, that parental T-cells with which the mice were immunized, could give aspecific help to B-cells. These B-cells then started to produce autoantibodies exclusively against autoantigens which contained a repetitive determinant and which could cross-link the antigen receptors on B-cells. However, most epitopes on U- and Y-RNA associated proteins against which an antibody response has been found are not repetitive. With regard to immunoassays it may be stated that, the first ELISA's in which recombinant antigens are used have now been described. The use of recombinant antigens in these (quantitative) assays will probably increase in the near future. The clinical significance of quantitation of these autoantibodies has not yet been established. [ABSTRACT FROM AUTHOR]