Two zinc(II) phthalocyanines (ZnPcs) were conjugated with a monoclonal antibody (MAb) directed against carcinoembryonic antigen (CEA), using an in situ activated carboxylic acid on the ZnPcs . The bioconjugate with the highest ZnPc /MAb ratio of 3 was investigated in vitro for its ability to target and fluorescently label human colorectal HT-29 cells. The ZnPc -CEA MAb 2 was observed to efficiently target HT-29 cells, about 37 times more than unconjugated ZnPc . Furthermore, in the presence of a 4-fold excess of unlabelled anti-CEA antibody, the fluorescence signal of 2 was reduced by ~90% showing that the targeting is CEA-mediated. These studies further confirm the high specificity of Pc-antibody conjugates for antigens over-expressed on tumor cells and warrant further investigations of these immunoconjugates and their derivatives for imaging of colorectal cancer.

中文翻译：

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用于结直肠癌成像的 ZnPc-antiCEA 生物偶联物的合成和生物学研究

使用 ZnPcs 上的原位活化羧酸，将两种锌 (II) 酞菁 (ZnPcs) 与针对癌胚抗原 (CEA) 的单克隆抗体 (MAb) 缀合。在体外研究了具有最高 ZnPc /MAb 比率为 3 的生物偶联物靶向和荧光标记人类结肠直肠 HT-29 细胞的能力。观察到 ZnPc -CEA MAb 2 可有效靶向 HT-29 细胞，比未结合的 ZnPc 高约 37 倍。此外，在存在 4 倍过量的未标记抗 CEA 抗体的情况下，2 的荧光信号降低了约 90%，表明靶向是 CEA 介导的。