Displaying antibodies on carrier surfaces facilitates precise targeting and delivery of drugs to diseased cells. Here, we report the synthesis of antibody-lipid conjugates (ALCs) through site-selective acetylation of Lys 248 in human Immunoglobulin G (IgG) and the development of antibody-functionalized red blood cells (immunoRBC) for targeted drug delivery. ImmunoRBC with the HER2-selective antibody trastuzumab displayed on the surface (called Tras-RBC) was constructed following a three-step procedure. First, a peptide-guided, proximity-induced reaction transferred an azidoacetyl group to the ε-amino group of Lys 248 in the Fc domain. Second, the azide-modified IgG was subsequently conjugated with dibenzocyclooctyne (DBCO)-functionalized lipids strain-promoted azide–alkyne cycloaddition (SPAAC) to result in ALCs. Third, the lipid portion of ALCs was then inserted into the cell membranes, and IgGs were displayed on red blood cells (RBCs) to construct immunoRBCs. We then loaded Tras-RBC with a photosensitizer (PS), Zinc phthalocyanine (ZnPc), to selectively target HER2-overexpressing cells, release ZnPc into cancer cells following photolysis, and induce photodynamic cytotoxicity in the cancer cells. This work showcases assembling immunoRBCs following site-selective lipid conjugation on therapeutic antibodies and the targeted introduction of PS into cancer cells. This method could apply to the surface functionalization of other membrane-bound vesicles or lipid nanoparticles for antibody-directed drug delivery.

中文翻译：

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用于红细胞表面功能化和靶向药物输送的位点选择性抗体-脂质缀合物

在载体表面展示抗体有利于药物的精确靶向和递送至患病细胞。在此，我们报告了通过人免疫球蛋白 G (IgG) 中第 248 位赖氨酸的位点选择性乙酰化合成了抗体-脂质缀合物 (ALC)，并开发了用于靶向药物递送的抗体功能化红细胞 (immunoRBC)。表面展示有 HER2 选择性抗体曲妥珠单抗的免疫红细胞（称为 Tras-RBC）按照三步程序构建。首先，肽引导的邻近诱导反应将叠氮乙酰基转移至 Fc 结构域中 Lys 248 的 ε-氨基。其次，叠氮化物修饰的 IgG 随后与二苯并环辛炔 (DBCO) 功能化脂质菌株促进的叠氮化物-炔环加成 (SPAAC) 结合，形成 ALC。第三，然后将ALC的脂质部分插入细胞膜，并将IgG展示在红细胞（RBC）上以构建免疫RBC。然后，我们将光敏剂 (PS) 酞菁锌 (ZnPc) 负载到 Tras-RBC 上，选择性地靶向 HER2 过表达细胞，在光解后将 ZnPc 释放到癌细胞中，并在癌细胞中诱导光动力细胞毒性。这项工作展示了在治疗性抗体上进行位点选择性脂质缀合后组装免疫红细胞，并将 PS 靶向引入癌细胞。该方法可应用于其他膜结合囊泡或脂质纳米粒子的表面功能化，用于抗体导向的药物递送。