Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain.
Eur J Pharm Sci. 2013 Jul 16;49(4):556-64. doi: 10.1016/j.ejps.2013.05.027. Epub 2013 Jun 7.
One strategy used to transport pharmacologically active substances across the blood-brain barrier (BBB) is to link the substance to a molecule capable of crossing the BBB using a receptor-mediated transcellular transport system in brain capillary endothelial cells. The transferrin receptor (TfR) is related to a transcytosis process in these cells, and the 8D3 antibody, directed against mouse TfR, is able to induce a receptor response. In this work, the potential of 8D3 to carry molecules across the BBB was investigated. This antibody (either unlabeled or FITC-labeled) was intravenously administered to ICR-CD1 mice. Immunocomplexes (ICs) consisting of 8D3 antibody (carrier) and Fab' fragments (simulated cargo), in some cases directly fluorolabeled with FITC, were also administered to ICR-CD1 mice. At different time-points of recirculation, the IC components were studied using immunohistochemical procedures and fluorescence resonance energy transfer (FRET). The results suggested that 8D3 alone or in an IC with Fab' fragments entered the endothelial cells. FRET analysis indicated that the colocalization of their fluorescent signals inside the endothelial cells decreased with time, indicating that ICs can be processed and Fab' fragments probably separated from 8D3. However, neither 8D3 alone nor the IC components crossed the BBB.
一种用于将具有药理活性的物质穿过血脑屏障（BBB）的策略是将该物质与能够通过脑毛细血管内皮细胞中的受体介导的细胞内转运系统穿过 BBB 的分子连接起来。转铁蛋白受体（TfR）与这些细胞中的转胞吞作用过程有关，针对小鼠 TfR 的 8D3 抗体能够诱导受体反应。在这项工作中，研究了 8D3 将分子穿过 BBB 的潜力。将未标记或 FITC 标记的这种抗体（8D3）静脉内给予 ICR-CD1 小鼠。也将由 8D3 抗体（载体）和 Fab'片段（模拟货物）组成的免疫复合物（IC）直接用 FITC 荧光标记后给予 ICR-CD1 小鼠。在再循环的不同时间点，使用免疫组织化学程序和荧光共振能量转移（FRET）研究 IC 成分。结果表明，8D3 本身或与 Fab'片段形成的 IC 进入内皮细胞。FRET 分析表明，其荧光信号在内皮细胞内的共定位随着时间的推移而减少，表明 IC 可以被处理并且 Fab'片段可能与 8D3 分离。然而，无论是 8D3 本身还是 IC 成分都没有穿过 BBB。
