Chua Jennifer, Mathur Devina, Lankford Hannah, Meinig J Matthew, Chabot Donald J, Legler Patricia M, Friedlander Arthur M
United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702, United States.
Center for Bio/molecular Science and Engineering, U.S. Naval Research Laboratories, Washington, District of Columbia 20375, United States.
ACS Omega. 2025 Jun 5;10(23):24862-24871. doi: 10.1021/acsomega.5c02119. eCollection 2025 Jun 17.
Polymers of d-glutamic acid (PDGA) form capsules of virulent strains of Bacillus anthracis. PDGA is antiphagocytic and weakly immunogenic; it enables the bacteria to evade innate immune responses. Capsule depolymerase (CapD) catalyzes the covalent anchoring of PDGA to the cell wall. There has been interest in developing CapD as a therapeutic to treat antibiotic-resistant anthrax infections. We previously showed that a His-tagged and circularly permuted (CP) CapD modified with a branched 3-prong polyethylene glycol (PEG) molecule termed PEG-CapD-CP could protect mice with 80% survival against a 5 LD challenge with virulent B. anthracis. In the current study, we compare the efficacy of tag-free CapD-CP modified by either the branched 3-prong or a linear 1-prong PEG. Pharmacokinetic studies in mice showed the branched 3-prong PEG-CapD-CP has a slightly higher, but not statistically different, total exposure in animals than the linear 1-prong PEG variant. The of the 1-prong PEG-CapD-CP was 8 times shorter than the 3-prong. Mice infected with spore doses of 10 and 100 LD, treated 24 h after infection every 8 h for 7 days, were protected by both the 3-prong (10 LD: = 0.0051; 100 LD: = 0.0463, log-rank analysis) and 1-prong (10 LD: = 0.0009; 100 LD: < 0.0001, log-rank analysis) PEG-CapD-CP when compared with control animals. A second iteration similarly showed statistically significant protection by both variants at both challenge doses, and the combined data from both experiments showed no significant difference in efficacy between the 1- and 3-prong enzymes confirming that tag-free PEG-CapD-CP is protective against experimental anthrax infection.
d -谷氨酸聚合物（PDGA）可形成炭疽芽孢杆菌强毒株的荚膜。PDGA具有抗吞噬作用且免疫原性较弱；它使细菌能够逃避先天免疫反应。荚膜解聚酶（CapD）催化PDGA共价锚定到细胞壁上。人们一直对开发CapD作为治疗耐抗生素炭疽感染的疗法感兴趣。我们之前表明，一种用分支三齿聚乙二醇（PEG）分子修饰的带有组氨酸标签的环化排列（CP）CapD，即PEG - CapD - CP，可使80%的小鼠在受到强毒炭疽芽孢杆菌5倍致死剂量的攻击后存活。在当前研究中，我们比较了由分支三齿或线性单齿PEG修饰的无标签CapD - CP的疗效。在小鼠身上进行的药代动力学研究表明，分支三齿PEG - CapD - CP在动物体内的总暴露量略高于线性单齿PEG变体，但无统计学差异。单齿PEG - CapD - CP的半衰期比三齿的短8倍。感染了10和100倍致死剂量芽孢的小鼠，在感染后24小时开始每8小时治疗一次，持续7天，与对照动物相比，三齿（10倍致死剂量：P = 0.0051；100倍致死剂量：P = 0.0463，对数秩分析）和单齿（10倍致死剂量：P = 0.0009；100倍致死剂量：P < 0.0001，对数秩分析）PEG - CapD - CP均能保护小鼠。第二次实验同样表明，在两种攻击剂量下，两种变体均具有统计学意义的保护作用，并且两个实验的综合数据显示，单齿和三齿酶在疗效上无显著差异，这证实了无标签PEG - CapD - CP对实验性炭疽感染具有保护作用。
