the present invention provides a process for preparing a carbohydrate - binding lectin derivative for use as immune modulators or immunoconjugates . the polymer - lectin conjugate produced in accordance with the process is polyethylene glycol ricinus communis agglutinin i . the lectin is coupled to the polymer by activating the polymer with a coupling agent such as 1 , 1 - carbonyldiimidazole . the polymer - lectin conjugate is biologically active , biocompatible and is expected to be substantially non - immunogenic .