Zhang Xiaobin, Wang Xin Xiang, Shusta Eric V
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA.
AIChE J. 2014 Apr 1;60(4):1245-1252. doi: 10.1002/aic.14348.
Antibodies that target and internalize into blood-brain barrier (BBB) endothelial cells offer promise as drug delivery agents. Previously, we identified a single-chain antibody (scFvA) capable of binding to the BBB. In an attempt to improve the binding and internalization properties of the single chain antibody (scFvA), a biotinylation tag (Avitag) was fused to scFvA and the protein secreted by yeast. The scFvA-Avitag could be biotinylated by yeast-displayed BirA enzyme and biotinylated scFvA-Avitag could be used to create scFv tetramers. Tetramerization of scFvA improved the internalization of scFvA into BBB endothelial cells, and biotinylated scFvA-Avitag could also be used to target streptavidin-coated quantum dots for BBB endothelial cell internalization. Perfusing the rat brain with scFvA-tetramer confirmed that the antigen targeted by scFvA is distributed on blood side of the BBB, suggesting the potential for downstream application of scFvA in brain-targeted drug delivery.
靶向血脑屏障（BBB）内皮细胞并内化的抗体有望成为药物递送剂。此前，我们鉴定出一种能够与血脑屏障结合的单链抗体（scFvA）。为了改善单链抗体（scFvA）的结合和内化特性，将生物素化标签（Avitag）与scFvA以及酵母分泌的蛋白质融合。scFvA-Avitag可被酵母展示的BirA酶生物素化，生物素化的scFvA-Avitag可用于创建scFv四聚体。scFvA的四聚化改善了scFvA向内皮细胞的内化，生物素化的scFvA-Avitag也可用于靶向链霉亲和素包被的量子点以实现血脑屏障内皮细胞内化。用scFvA-四聚体灌注大鼠脑证实，scFvA靶向的抗原分布在血脑屏障的血液侧，这表明scFvA在脑靶向药物递送中的下游应用潜力。
