Hydrazido-agarose was prepared and used for the site-specific immobilization of antibody. Antibody was oxidized with sodium periodate, resulting in the production of aldehyde on the carbohydrate moiety. The oxidized antibody was then reacted with the hydrazido-agarose to form stable hydrazone linkages. The method of immobilization resulted in an increased activity and stability of the bound antibody. TNF, γ-IFN and IL-2 were purified by chromatography on immunosorbents prepared with monoclonal antibodies using this method respectively. Their activities were tested.