Immuno-capillary electrophoresis for the characterization of a monoclonal antibody against DNA

A monoclonal antibody against DNA established from a mouse strain that spontaneously develops systemic lupus erythematosus was characterized by migration shift immuno-capillary electrophoresis. The minimal size for DNA binding antibody was > 16 bases and the interaction with a double-stranded 32-mer oligonucleotide was almost one order of magnitude stronger than the interaction with a single-stranded oligonucleotide. The binding was highly dependent on the ionic strength conditions with an increase in binding with a decrease in ionic strength. The estimate of the dissociation constant for the antibody binding of a single stranded 32-mer oligonucleotide was 0.62 microM at pH 7.90. This value was in good agreement with the value of 0.44 microM measured by an independent method using biosensor (surface plasmon resonance) technology.