Novel preparation method of immunogen for hydrophobic hapten, enzyme immunoassay for daunomycin and adriamycin

The present study was undertaken to develop a novel method of preparing a hydrophobic hapten as immunogen. The anticancer drug, daunomycin (DM) was used as prototype and coupled to mercaptosuccinylated bovine serum albumin (MS, BSA) with N-(gamma-maleimidobutyryloxy)succinimide (GMBS). Injection of rabbits with a conjugate (DM-GMBS-MS.BSA) which contained 7.3 DM per BSA molecule produced good levels of anti-DM antibody which was detected by the reaction of diluted antiserum with beta-D-galactosidase-labeled DM. beta-D-galactosidase-labeled DM was used to develop a double antibody enzyme immunoassay for DM and for the DM homologue adriamycin (AM) which reproducibly detected as little as 1 pmole of either drug. A variety of commonly used other anticancer drugs were tested and had little reactivity in this immunoassay. These studies indicate that the anti-DM serum produced is highly specific.