Inventors:
Gowsala Sivam - Edmonds WA
International Classification:
C07D20740
G01N 33536
C07K 100
Abstract:
Method for producing an immunoconjugate comprising the steps of reacting a toxin or protein with a heterobifunctional reagent having the following general formula: ##STR1## where R. sub. 1 is: ##STR2## where n=1 to 10; and where R. sub. 2 is selected from the group consisting of o- and p-nitrophenyl, 2-chloro-4-nitrophenyl, cyanomethyl, 2-mercaptopyridyl, hydroxybenztriazole, N-hydroxysuccinimide, trichlorophenyl, tetrafluorophenyl, 2-fluorophenyl, 4-fluoropheyl, 2,4-difluorophenyl, o-nitro-p-sulfophenyl, N-hydroxyphthalimide, N,N-diethylamino, N-hydroxypyrrolidone, tetrafluorothiophenyl, and 2,3,5,6-tetrafluorophenyl, under reactive conditions, thereby forming a derivatized toxin or protein. The derivatized toxin or protein is separated from the reaction mixture and combined with an antibody or antibody fragment under reactive conditions, such that at least one native disulfide bond is reduced to produce at least one thiol group, capable of forming a thioether bond between said thiol group and the maleimide group of said derivatized toxin, or protein thereby forming an immunoconjugate. The preferred heterobifunctional linking group is succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC).