Kojima S, Nakamura N, Ueno Y, Yamaguchi T, Takahashi T
Research Institute for Biosciences, Science University of Tokyo, Chiba, Japan.
Nat Toxins. 1993;1(4):209-15. doi: 10.1002/nt.2620010402.
Monoclonal antibody A7 (A7 MoAb), from splenocytes of a mouse immunized against human colorectal carcinoma, was used as a T-2 toxin (T-2) carrier targeting colon cancer. T-2 was converted to T-2 hemiglutarate by glutaric anhydride treatment, and T-2-A7 MoAb conjugates containing up to 20 T-2 per antibody molecule were obtained from the antibody and T-2 hemiglutarate activated with N-hydroxysuccinimide. The in vitro cytotoxicity against human colon cancer (LS174T) cells indicated that the conjugates were markedly less toxic than the toxin itself. The immunoreactivity was evaluated from the in vitro binding activity of A7 MoAb with LS174T cells, and from the in vivo localization in LS174T-bearing nude mice; it remained essentially intact after conjugation with T-2. The efficacy of the T-2-A7 MoAb conjugate was tested against LS174T-bearing nude mice. The conjugate significantly suppressed the growth of the tumor in comparison with both phosphate-buffered saline and free T-2. These results suggest that the conjugate of T-2 with A7 MoAb might be useful as a selective immunotoxin for cancer immunotherapy, with less serious side effects than T-2.
单克隆抗体A7（A7单克隆抗体）取自免疫过的小鼠脾脏细胞，该小鼠以人结肠直肠癌作为抗原进行免疫，A7单克隆抗体用作靶向结肠癌的T-2毒素（T-2）载体。通过戊二酸酐处理将T-2转化为T-2半戊二酸酯，并且从用N-羟基琥珀酰亚胺活化的抗体和T-2半戊二酸酯中获得每个抗体分子含有多达20个T-2的T-2-A7单克隆抗体缀合物。对人结肠癌细胞（LS174T）的体外细胞毒性表明，该缀合物的毒性明显低于毒素本身。通过A7单克隆抗体与LS174T细胞的体外结合活性以及在携带LSJ74T的裸鼠体内的定位来评估免疫反应性；与T-2缀合后，其基本保持完整。在携带LS174T的裸鼠上测试了T-2-A7单克隆抗体缀合物的疗效。与磷酸盐缓冲盐水和游离T-2相比，该缀合物显著抑制了肿瘤的生长。这些结果表明，T-2与A7单克隆抗体的缀合物可能作为癌症免疫治疗的选择性免疫毒素有用，其副作用比T-2轻。
