Immunoglobulin: DNA cofactor interaction

Abstract

The reasons for the appearance of DNA-binding activity of immunoglobulins (Ig) after chromatography on anion-exchange Sephadexes were studied. Elution of Ig from these Sephadexes with 0.5 M NaCl was found, using an orcinol method, to be associated with degradation of the matrix, with the appearance of water-soluble fragments (WSF) of Sephadex in the eluate. Degradation of the Sephadex matrix also occurred on washing of unloaded Sephadex. Monoclonal antibodies which did not initially interact with DNA acquired the ability to react with DNA after incubation with Sephadex WSF, as demonstrated using immunoenzyme analysis. It is suggested that the WSF forming on passage of Ig through anion exchange Sephadex columns interact with Ig to generate cations which can react with negatively charged antigens and, particularly DNA. 289 0091-150X/07/4106-0289