Tyrosinase-Mediated Synthesis of Nanobody–Cell Conjugates

A convenient enzymatic strategy is reported for the modification of cell surfaces. Using a tyrosinase enzyme isolated from Agaricus bisporus, unique tyrosine residues introduced at the C-termini of nanobodies can be site-selectively oxidized to reactive o-quinones. These reactive intermediates undergo rapid modification with nucleophilic thiol, amine, and imidazole residues present on cell surfaces, producing novel nanobody–cell conjugates that display targeted antigen binding. We extend this approach toward the synthesis of nanobody–NK cell conjugates for targeted immunotherapy applications. The resulting NK cell conjugates exhibit targeted cell binding and elicit targeted cell death.本研究报道了一种用于细胞表面修饰的便捷酶促策略。采用从双孢蘑菇（Agaricus bisporus）中分离得到的酪氨酸酶（tyrosinase），可将预先在纳米抗体（nanobodies）C端（C-termini）引入的独特酪氨酸残基进行位点选择性氧化，生成具有反应活性的邻醌（o-quinones）中间体。此类活性中间体可与细胞表面存在的亲核性巯基（thiol）、氨基（amine）及咪唑基（imidazole）残基快速发生修饰反应，进而得到具备靶向抗原结合活性的新型纳米抗体-细胞偶联物（nanobody–cell conjugates）。本研究将该策略拓展至靶向免疫治疗（targeted immunotherapy）用纳米抗体-NK细胞（NK cell）偶联物的合成，所得NK细胞偶联物展现出靶向细胞结合能力，并可诱导靶向性细胞死亡。