Assay of antinuclear antibodies by ELISA using nuclei as antigen

An enzyme-linked immunosorbent assay to detect antinuclear antibodies in the sera of patients with autoimmune diseases is described. Goat liver nuclei were immobilized on polystyrene plates and antinuclear antibodies were used to standardize the assay. The effects of variables, such as the nuclei concentration, conditions of nuclei storage, and the length of the incubation period were investigated on the assay. Prototype sera with known antibody specificity were used to evaluate the assay. The method described is highly sensitive, autoantibodies being detectable at serum dilutions of 1:1000 or higher. According to the intra- and inter-assay coefficient of variation, the results were highly reproducible.