POLYMERIC IMMUNOGLOBULIN RECEPTOR TARGETING OF AIRWAYS

描述（由申请人提供）：多聚免疫球蛋白受体（plgR）在气道上皮细胞和粘膜下腺体的浆液细胞中表达。 其正常功能是结合基底外侧表面上的聚合免疫球蛋白，并将其转移到顶端表面（管腔），在那里它们被释放，仍然结合到受体的一部分（现在称为分泌组分，或SC）作为分泌免疫球蛋白。 它特别适合于将大量货物转移穿过上皮，并且它在气道中的细胞类型中表达，其中囊性纤维化跨膜传导调节因子也表达。 因此，从治疗的角度来看，这种受体是两个目的的候选者-一个是从基底外侧途径将基因递送到气道上皮，另一个是将治疗药物从血液运送到气道管腔。 已经制备了针对该受体的抗体，并且应用了要求它们也与分泌性免疫球蛋白反应（即，在天然配体所使用的位点之外的位点处结合）的二次筛选。 这些抗体分为两类。 一类经历快速转胞吞作用。 另一种被迅速摄取，但保留在细胞内的膜结合的核周囊泡中。 该建议基于这样的假设，即“快速转胞吞”抗体将产生上级转胞吞治疗载体，而“细胞滞留”抗体对于基因转移将是上级的，因为它们将使其货物在细胞中保持更长时间，从而允许逃逸和核进入。 将从两类抗体的代表制备单链Fv，并比较它们增强从压实DNA的非病毒基因转移载体的基因转移的能力，以及它们作为融合蛋白将潜在的治疗分子1-抗胰蛋白酶转运到气道腔中的能力。 测试系统将是用人plgR转染的培养物中的极化细胞系;在空气-液体界面生长的表达plgR的人气道上皮细胞;以及由CC-10启动子驱动的人plgR转基因小鼠，使得受体仅在气道上皮中表达。 如果研究成功，可以在此基础上开发囊性纤维化和其他气道疾病的新疗法。

DESCRIPTION (provided by applicant): The polymeric immunoglobulin receptor (plgR) is expressed in airway epithelial cells and in the serous cells of the submucosal glands. Its normal function is to bind to polymeric immunoglobulins on the basolateral surface and transfer them to the apical surface (the lumen) where they are released, still bound to a portion of the receptor (now called secretory component, or SC) as secretory immunoglobulins. It is specifically adapted to transfer large amounts of cargo across the epithelium, and it is expressed in the cell types in the airway in which the cystic fibrosis transmembrane conductance regulator is also expressed. Thus, from the therapeutic perspective, this receptor is a candidate for two purposes - one, to deliver genes to airway epithelium from the basolateral approach, and two, to ferry therapeutics across the airway from the blood to the lumen. Antibodies have been prepared against this receptor, and a secondary screen requiring them to react with secretory immunoglobulin as well (that is, to bind at a site other than that used by the natural ligand) was applied. These antibodies fall into two categories. One class undergoes rapid transcytosis. The other undergoes rapid uptake, but is retained within the cell in membrane-bounded perinuclear vesicles. This proposal is based on the hypothesis that the "rapid transcytosis" antibodies will produce superior transcytotic therapeutic carriers, whereas the "cell retention" antibodies will be superior for gene transfer, for they will keep their cargo in the cells longer, allowing for escape and nuclear entry. Single chain Fvs will be prepared from representatives of both classes of antibodies and compared for their ability to enhance gene transfer from nonviral gene transfer vectors of compacted DNA, and for their ability to transport, as a fusion protein, a potential therapeutic molecule, 1-antitrypsin, into the airway lumen. Test systems will be both polarized cell lines in culture transfected with the human plgR; human airway epithelial cells grown at the air-liquid interface, which express plgR; and mice transgenic for the human plgR driven by the CC-10 promoter, so that the receptor is expressed only in airway epithelium. If the studies are successful, new therapeutics for cystic fibrosis and other airway diseases can be developed from this base.