Buffalo BioLabs, LLC, Buffalo, NY, USA.
Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
Commun Biol. 2021 Apr 12;4(1):466. doi: 10.1038/s42003-021-01978-6.
The Toll-like receptor 5 (TLR5) agonist entolimod, a derivative of Salmonella flagellin, has therapeutic potential for several indications including radioprotection and cancer immunotherapy. However, in Phase 1 human studies, entolimod induced a rapid neutralizing immune response, presumably due to immune memory from prior exposure to flagellated enterobacteria. To enable multi-dose applications, we used structure-guided reengineering to develop a next-generation, substantially deimmunized entolimod variant, GP532. GP532 induces TLR5-dependent NF-κB activation like entolimod but is smaller and has mutations eliminating an inflammasome-activating domain and key B- and T-cell epitopes. GP532 is resistant to human entolimod-neutralizing antibodies and shows reduced de novo immunogenicity. GP532 also has improved bioavailability, a stronger effect on key cytokine biomarkers, and a longer-lasting effect on NF-κB. Like entolimod, GP532 demonstrated potent prophylactic and therapeutic efficacy in mouse models of radiation-induced death and tissue damage. These results establish GP532 as an optimized TLR5 agonist suitable for multi-dose therapies and for patients with high titers of preexisting flagellin-neutralizing antibodies.
Toll 样受体 5（TLR5）激动剂 Entolimod 是沙门氏菌鞭毛蛋白的衍生物，具有多种适应症的治疗潜力，包括放射防护和癌症免疫治疗。然而，在 1 期人体研究中，Entolimod 诱导了快速的中和免疫反应，推测是由于先前暴露于鞭毛肠杆菌而产生了免疫记忆。为了实现多剂量应用，我们使用结构引导的重新设计开发了下一代、大大去免疫化的 Entolimod 变体 GP532。GP532 像 Entolimod 一样诱导 TLR5 依赖性 NF-κB 激活，但体积更小，并且具有突变，消除了炎症小体激活结构域和关键的 B 细胞和 T 细胞表位。GP532 对人 Entolimod 中和抗体具有抗性，并且显示出降低的新抗原性。GP532 还具有改善的生物利用度、对关键细胞因子生物标志物更强的作用以及对 NF-κB 更长的作用。与 Entolimod 一样，GP532 在放射诱导的死亡和组织损伤的小鼠模型中表现出强大的预防和治疗功效。这些结果确立了 GP532 作为一种优化的 TLR5 激动剂，适合多剂量治疗和高滴度预先存在的鞭毛蛋白中和抗体的患者。
