Natural hidden autoantibodies react with negatively charged carbohydrates and xenoantigen Bdi.

Immunoglobulin preparations from sera of healthy donors contain polyspecific autoantibodies interacting with DNA and other charged antigens. These antibodies belong to the IgG class and can exist in the free or hidden state. The hidden antibody activity can be revealed after ion-exchange chromatography on QAE-Sephadex A-50. Immunoenzyme assay was used to assess the interactions of both free and hidden antibodies with different carbohydrates. The hidden antibodies were only able to interact with different polyanionic carbohydrates and neutral xenoantigen Bdi.