Abstract: A lectin is covalently bonded to an immunological conjugate such as an antibody-antigen or its equivalent. Then, the lectin-conjugate is isolated from the reaction product mixture by one of a number of alternative techniques involving one or more of the following types of reaction; (1) reversible reaction of the lectin with an insolubilized sugar to isolate lectin from the remainder of the mixture, (2) reaction of one immunological component (e.g., antibody) bonded to the lectin with an insolubilized corresponding component (e.g., antigen) to separate the antibody components from the remainder of the reaction mixture, and (3) filtration of the reaction components to separate on the basis of product molecular weight, size and/or shape of the components.