Biochemical aspects of immunotoxin preparation.

The preparation of immunotoxins, hybrid proteins formed by disulfide bonding an antibody and the A-chain of ricin, has been studied in detail. Optimal conditions, both for the modification of the antibody and the coupling reaction between the modified antibodies and the toxin subunit, have been determined. Conditions of time, temperature and stoichiometry studied suggested 2 protocols for each of the 2 steps of this preparation. Purification and analysis of the physicochemical and biochemical properties of the products yielded well-characterized agents, likely to be of value in clinical studies.