Yarkoni Shai, Sagiv Yuval, Kaminitz Ayelet, Farkas Daniel L, Askenasy Nadir
GASR Biotechnology Ltd., Kfar-Saba, Israel.
Eur J Immunol. 2009 Oct;39(10):2850-64. doi: 10.1002/eji.200839190.
Pathogenic lymphocytes in the enteric wall of inflammatory bowel disease patients display various abnormalities, including reduced sensitivity to apoptosis. We evaluated a therapeutic approach to elimination of cytotoxic cells, using two IL-2 fusion proteins, a diphtheria toxin (IL2-DT) and a caspase-3 (IL2-cas) conjugate. In models of acute (dextran sodium sulfate and trinitrobenzene sulfonic acid) and chronic (dextran sodium sulfate) toxic colitis, therapeutic doses of the fusion proteins improved survival and prevented colon shortening. While both chimeric proteins eradicated CD4(+)CD25(+)Foxp3(+) T cells in mesenteric LN, IL2-DT caused severe lymphopenia. In contrast, IL2-cas was equally protective and increased fractional expression of Foxp3. Similar effects of the fusion proteins were observed in healthy mice: IL2-DT caused lymphopenia and IL2-cas increased fractional expression of FoxP3. The fusion proteins induced apoptosis in CD25(+) T cells in vitro, with lower toxicity of IL2-cas to Foxp3(+) T cells. These data infer that targeted depletion of cells expressing the IL-2 receptor has therapeutic potential in models of inflammatory colitis, despite depletion of CD25(+) Treg. The IL2-cas fusion protein is particularly relevant to inflammatory bowel disease, as direct internalization of toxic moieties overcomes multiple pathways of resistance to apoptosis of colitogenic T cells.
炎症性肠病患者肠壁中的致病性淋巴细胞表现出各种异常，包括对细胞凋亡的敏感性降低。我们评估了一种消除细胞毒性细胞的治疗方法，使用两种白细胞介素-2融合蛋白，一种白喉毒素（IL2-DT）和一种半胱天冬酶-3（IL2-cas）缀合物。在急性（葡聚糖硫酸钠和三硝基苯磺酸）和慢性（葡聚糖硫酸钠）毒性结肠炎模型中，治疗剂量的融合蛋白提高了生存率并防止了结肠缩短。虽然两种嵌合蛋白都消除了肠系膜淋巴结中的CD4(+)CD25(+)Foxp3(+) T细胞，但IL2-DT导致严重的淋巴细胞减少。相比之下，IL2-cas具有同样的保护作用，并增加了Foxp3的分数表达。在健康小鼠中也观察到了融合蛋白的类似效果：IL2-DT导致淋巴细胞减少，而IL2-cas增加了FoxP3的分数表达。融合蛋白在体外诱导CD25(+) T细胞凋亡，IL2-cas对Foxp3(+) T细胞的毒性较低。这些数据表明，尽管CD25(+)调节性T细胞会减少，但靶向清除表达白细胞介素-2受体的细胞在炎症性结肠炎模型中具有治疗潜力。IL2-cas融合蛋白与炎症性肠病特别相关，因为有毒部分的直接内化克服了致结肠炎T细胞对细胞凋亡的多种抵抗途径。
