Department of Biomedical Sciences, University at Albany, Albany, New York 12201, United States.
Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York 12208, United States of America.
Biochemistry. 2024 Oct 1;63(19):2391-2396. doi: 10.1021/acs.biochem.4c00385. Epub 2024 Sep 19.
Expression of camelid-derived, single-domain antibodies (VHs) within the cytoplasm of mammalian cells as "intrabodies" has opened up novel avenues for medical countermeasures against fast-acting biothreat agents. In this report, we describe a heterodimeric intrabody that renders Vero cells virtually impervious to ricin toxin (RT), a potent Category B ribosome-inactivating protein. The intrabody consists of two structurally defined VHs that target distinct epitopes on RT's enzymatic subunit (RTA): V9E1 targets RTA's P-stalk recruitment site, and V2A11 targets RTA's active site. Resistance to RT conferred by the biparatopic VH construct far exceeded that of either of the VHs alone and effectively inhibited all measurable RT-induced cytotoxicity . We propose that the targeted delivery of bispecific intrabodies to lung tissues may represent a novel means to shield the airways from the effects of inhalational RT exposure.
骆驼科来源的单域抗体（VHs）在哺乳动物细胞质内作为“内抗体”的表达为针对快速作用的生物威胁剂的医学对策开辟了新的途径。在本报告中，我们描述了一种杂二聚体内抗体，使 Vero 细胞对蓖麻毒素（RT）几乎具有抗药性，RT 是一种有效的 B 类核糖体失活蛋白。该内抗体由两个结构上定义的 VH 组成，它们针对 RT 的酶亚基（RTA）上的不同表位：V9E1 靶向 RTA 的 P 茎募集位点，而 V2A11 靶向 RTA 的活性位点。由双价 VH 构建体赋予的对 RT 的抗性远远超过单独任何一个 VH 的抗性，并有效地抑制了所有可测量的 RT 诱导的细胞毒性。我们提出，将双特异性内抗体靶向递送至肺组织可能代表一种新的手段，可使气道免受吸入性 RT 暴露的影响。
