Aggregation of chlorambucil in vitro may cause misinterpretation of protein binding data

Eradication of Murine Lymphoma and Melanoma Cells by Chlorambucil‐Antibody Complexes

“…Surprisingly, such problems as anaphylactic reaction of tumor enhancement are only rarely mentioned. A problem in noncovalent linking of chlorambucil to antibody is the possible formation of aggregates of chlorambucil (Blakeslee et al 1975). The alkylating agent chlorambucil was physically linked to the antibodies according to the method described by Blakeslee & Kennedy (1974).…”

“…Cumulative energy of multiple ionic and other noncovalent bonds between two molecules has also been shown to produce very stable complexes (Szekerke et al 1972b. A problem in noncovalent linking of chlorambucil to antibody is the possible formation of aggregates of chlorambucil (Blakeslee et al 1975). The presence of these aggregates might lead to overestimation of the amount of active chlorambucil which is physically linked to the antibody.…”

A chlorambucil-anti-CEA conjugate cytotoxic for human colon adenocarcinoma cells in vitro

“…Many authors have already described a method to adsorb chlorambucil to antitumour antibodies (Blakeslee & Kennedy,1974;Guclu et al, 1976), but in the previous applications of chlorambucilantibody conjugates, a certain percentage of the reported activity could have been due to the presence of a non-covalently bound aggregate of the drug (Blakeslee et al, 1975). The other method described for the covalent coupling of CBL (Tai et al, 1979) could lead to polymerisation of the carrier and needed a 2 h incubation in an aqueous solution.…”