Antitumor Effects of Antibody-Diphtheria Toxin Conjugates: Use of Hapten-Coated Tumor Cells as an Antigenic Target2

Abstract

Diphtheria toxin was conjugated to rabbit antidinitrophenyl (anti-DNP) antibodies, and the resulting conjugate was extensively purified by immunoadsorbent techniques. An artificial “tumor-associated antigen” was created by attachment of DNP groups to hamster sarcoma cells. In hamsters given injections of DNP-coated sarcoma cells, treatment with the toxin-anti-DNP conjugate delayed the appearance of tumors and prolonged the lifespan of the treated animals. When only 3×10² cells were injected, this treatment also reduced tumor incidence. These results suggest that antibody-toxin conjugates may prove useful as antitumor agents, if improved methods can be found for preparation of purified conjugates directed against naturally occurring tumor antigens.—J Natl Cancer Inst 49: 1057–1062, 1972.