Detection of Pt (1R, 2R-diaminocyclohexane) bound to DNA in Cancer Cell by Monoclonal Antibody

用Pt（1 R，2 R-dach）Cl_2修饰的小牛胸腺DNA免疫小鼠，获得了与抗肿瘤药物Pt（1 R，2 R-diaminocyclohexane）Cl_2Pt（1 R，2 R-dach）在DNA上形成的加合物选择性结合的单克隆抗体。单克隆抗体与铂的结合（1 R，2 R-dach）修饰的DNA被竞争性抑制（50%对照）在酶联免疫吸附试验（ELISA）中通过147 nM浓度的Pt（1 R，2 R-dach）结合到DNA。稍高浓度（272 nM）的Pt（1 R，2S-dach）修饰的DNA也能抑制抗体结合，而抑制作用需要较高浓度（2450 nM）的cis-Pt（NH_3）_2-DNA加合物。DNA不抑制抗体与Pt（1 R，2 R-dach）-DNA的结合，反式-Pt（NH_3）_2-DNA不与抗体形成加合物，因此单克隆抗体识别的是双功能的Pt-DNA加合物。含环己基的铂配合物（Pt（1 R，2 R-dach）-DNA，Pt（1 R，2S-dach）-DNA）比顺式Pt（NH_3）_2-DNA具有更高的活性，说明抗体识别抗原的环己基部分。

Murine monoclonal antibodies that bind selectively to adducts formed on DNA by the antitumor drug Pt (1R, 2R-diarminocyclohexane) Cl_2 Pt (1R, 2R-dach), were elicited by immunization with calf thymus DNA modified with Pt (1R, 2R-dach)Cl_2 at the ratio of bound platinum per nucleotide of 0.075. The binding of monoclonal antibody to Pt (1R, 2R-dach) -modified DNA was competitively inhibited (50% control) in an enzyme-linked immunosorbent assay (ELISA) by 147 nM concentrations of Pt (1R, 2R-dach) bound to DNA.Slightly larger concentrations (272 nM) of Pt (1R, 2S-dach) modified DNA also inhibited antibody binding, where- as higher concentrations (2450 nM) of cis-Pt (NH_3)_2-DNA adduct were required for inhibition. DNA did not inhibit antibody binding to Pt (1R, 2R-dach) -DNA.The inactive platinum complex, trans-Pt (NH_3)_2-DNA did not form antibody-detectable adducts on DNA.Therefore, monoclonal antibody recognized a bifunctional Pt-DNA adduct. The platinum complexes (Pt (1R, 2R-dach) -DNA, Pt (1R, 2S-dach) -DNA) which have cyclohexane ring has higher activities than cis-Pt (NH_3)_2-DNA.This behavior implies that the antibody recognizes the cyclohexan ring moiety of the antigen.