Do Tuan-Minh, Capdevila Cécile, Pradier Laurent, Blanchard Véronique, Lopez-Grancha Mati, Schussler Nathalie, Steinmetz Anke, Beninga Jochen, Boulay Denis, Dugay Philippe, Verdier Patrick, Aubin Nadine, Dargazanli Gihad, Chaves Catarina, Genet Elisabeth, Lossouarn Yves, Loux Christophe, Michoux François, Moindrot Nicolas, Chanut Franck, Gury Thierry, Eyquem Stéphanie, Valente Delphine, Bergis Olivier, Rao Ercole, Lesuisse Dominique
Rare and Neurologic Disease Research, Sanofi, Chilly Mazarin, France.
Biologics Research, Sanofi, Vitry-Sur-Seine, France.
Mol Ther Methods Clin Dev. 2020 Aug 21;19:58-77. doi: 10.1016/j.omtm.2020.08.014. eCollection 2020 Dec 11.
Most antibodies display very low brain exposure due to the blood-brain barrier (BBB) preventing their entry into brain parenchyma. Transferrin receptor (TfR) has been used previously to ferry antibodies to the brain by using different formats of bispecific constructs. Tetravalent bispecific tandem immunoglobulin Gs (IgGs) (TBTIs) containing two paratopes for both TfR and protofibrillar forms of amyloid-beta (Aβ) peptide were constructed and shown to display higher brain penetration than the parent anti-Aβ antibody. Additional structure-based mutations on the TfR paratopes further increased brain exposure, with maximal enhancement up to 13-fold in wild-type mice and an additional 4-5-fold in transgenic (Tg) mice harboring amyloid plaques, the main target of our amyloid antibody. Parenchymal target engagement of extracellular amyloid plaques was demonstrated using and fluorescence imaging as well as histological methods. The best candidates were selected for a chronic study in an amyloid precursor protein (APP) Tg mouse model showing efficacy at reducing brain amyloid load at a lower dose than the corresponding monospecific antibody. TBTIs represent a promising format for enhancing IgG brain penetration using a symmetrical construct and keeping bivalency of the payload antibody.
由于血脑屏障（BBB）阻止抗体进入脑实质，大多数抗体在脑中的暴露水平很低。转铁蛋白受体（TfR）此前已被用于通过不同形式的双特异性构建体将抗体转运至脑内。构建了含有两个针对TfR和淀粉样β（Aβ）肽原纤维形式的抗原结合位点的四价双特异性串联免疫球蛋白G（IgG）（TBTIs），并显示其脑渗透性高于亲本抗Aβ抗体。TfR抗原结合位点上基于结构的额外突变进一步增加了脑内暴露，在野生型小鼠中最大增强达13倍，在携带淀粉样斑块（我们淀粉样抗体的主要靶点）的转基因（Tg）小鼠中额外增加4至5倍。使用[具体方法1]和[具体方法2]荧光成像以及组织学方法证明了细胞外淀粉样斑块的实质靶点结合。在淀粉样前体蛋白（APP）Tg小鼠模型中对最佳候选物进行了慢性研究，结果显示其在比相应单特异性抗体更低剂量下降低脑淀粉样蛋白负荷方面具有疗效。TBTIs代表了一种有前景的形式，可通过对称构建体增强IgG脑渗透性并保持有效载荷抗体的双价性。
