Department of Surgery, Mannheim University Medical Center, University of Heidelberg, Mannheim, Germany.
Adv Exp Med Biol. 2013;756:203-12. doi: 10.1007/978-94-007-4549-0_26.
Vascular immunotargeting of catalase via angiotensin-converting-enzyme (ACE) attenuated lung ischemia reperfusion injury in the rat. As this might be a promising modality for extension of the viability of human lung grafts for transplantation we tested the hypothesis whether anti-ACE antibodies are suitable for human lung protection within the model of isolated perfused and ventilated human lung resections. Right after surgery for lung cancer, human lung specimens were isolated, ventilated and perfused under physiological conditions with 500 μg of either mouse monoclonal antibodies (mAb) to human ACE (9B9, I2H5, 3G8) or non-immune mouse IgG (as a negative control) followed by wash-out perfusion. Perfusion pressure, pH and lung weight gain were measured before and during perfusion. After mAb perfusion and wash-out perfusion period lung tissue was tested for the uptake of mAbs by immunohistochemistry and by enzyme-capture technique. Furthermore, antibody concentration and ACE shedding were measured within the perfusate. We found that ACE activity in tumor and normal lung tissue did not differ between the groups perfused with different mAbs. However, ACE activity in normal lung tissue (17.0 ± 6.0 U/g) was significantly higher compared to tumor tissue (6.0 ± 3.0; p < 0.01). Absolute retaining of mAbs was with 1.3 ± 1.1% of injected dose per gram of tissue in normal lung tissue, 0.7 ± 0.7% of injected dose per gram of tumor tissue and was significantly higher compared to non-immune mouse IgG (0.1 ± 0.1%/g; p < 0.01). Anti-ACE mAbs concentration in the perfusate dropped significantly to 47 ± 11% (p < 0.001) at 40 min of perfusion. No significant difference between different anti-ACE mAbs in the depletion from perfusate has been observed. mAb 9B9 showed the most intense immunostaining (i.e., most significant lung uptake) after each experiment in normal and tumor lung tissue compared to mAbs i2H5 and 3G8 (p < 0.01). These results validate the possibility of immunotargeting of pulmonary endothelium in the human lung tissue by anti-ACE mAbs under in vivo conditions. Furthermore, the model might be useful to investigate targeted therapies in lung cancer without side effects for the patient.
血管免疫靶向过氧化氢酶通过血管紧张素转换酶（ACE）减轻大鼠肺缺血再灌注损伤。由于这可能是延长人类供肺移植存活时间的一种有前途的方式，我们测试了以下假设：抗 ACE 抗体是否适合在离体灌注和通气的人肺切除模型中用于人类肺保护。在肺癌手术后，立即分离人肺标本，在生理条件下用 500μg 抗人 ACE 的单克隆抗体（9B9、I2H5、3G8）或非免疫性小鼠 IgG（作为阴性对照）进行通气和灌注，然后进行冲洗灌注。在灌注前和灌注期间测量灌注压、pH 值和肺重量增加。在 mAb 灌注和冲洗灌注期后，通过免疫组织化学和酶捕获技术检测肺组织对 mAb 的摄取。此外，还在灌注液中测量抗体浓度和 ACE 脱落。我们发现，用不同 mAb 灌注的肿瘤和正常肺组织中的 ACE 活性没有差异。然而，正常肺组织中的 ACE 活性（17.0±6.0 U/g）明显高于肿瘤组织（6.0±3.0；p<0.01）。正常肺组织中 mAb 的绝对保留率为每克组织 1.3±1.1%的注射剂量，肿瘤组织中为 0.7±0.7%的注射剂量，明显高于非免疫性小鼠 IgG（0.1±0.1%/g；p<0.01）。灌注液中的抗 ACE mAb 浓度在灌注 40 分钟时显著下降至 47±11%（p<0.001）。不同抗 ACE mAb 从灌注液中的耗竭没有明显差异。与 mAbs i2H5 和 3G8 相比，mAb 9B9 在每次实验后在正常和肿瘤肺组织中的免疫染色最强（即肺摄取最显著）（p<0.01）。这些结果验证了在体内条件下，抗 ACE mAb 对人肺组织中肺内皮的免疫靶向的可能性。此外，该模型可能有助于在不产生副作用的情况下研究肺癌的靶向治疗。
