Anti-sDNA antibody purified from sera of human patients with systemic lupus erythematosus—II: Ligand binding properties of purified antibodies

Abstract

Anti-sDNA antibodies were purified from various human SLE sera by immunoadsorption and analyzed for their nucleotide binding properties. Equilibrium dialysis studies with radioactivity labeled nucleotides show that the average intrinsic association constants were relatively low (10 4–10 5 M −1). Heterogeneity index values in general indicated that all antibody populations were quite heterogeneous. Comparative r values, calculated for antibody samples displaying multi-base specificity, indicated both mono-specific and cross reactive sub-populations. Antibody samples were also studied for binding properties with 32P-sDNA, and nucleotide inhibition of the polymer interaction. Certain purified antibody samples were studied using mononucleotide and dinucleotide inhibitors of the apparent homologous nucleotide reaction. Results of binding specificities are discussed in terms of pathological implications.