A ligand-bonded complex which does not react with a free target such as a soluble tumor antigen, but enables substantially specific reaction with a non-free target such as a tumor cell and a tumor antigen existing in the cell.
配体结合复合物,它不能与游离靶标(如可溶性肿瘤抗原)发生反应,但能与非游离靶标(如肿瘤细胞和存在于细胞中的肿瘤抗原)发生实质上特异的反应。