Jianhao Lai, Swati Shah, Neysha Martinez-Orengo, Rekeya Knight, Eyob Alemu, Mitchell L Turner, Benjamin Wang, Anna Lyndaker, Jianfeng Shi, Falguni Basuli, Dima A Hammoud
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In this study, the utility of antibodies and antibody fragments (Fab) targeting β-glucans in the fungal cell wall to detect Aspergillus infections was evaluated both in vitro and in preclinical mouse models.</p><p><strong>Methods: </strong>The binding characteristics of two commercially available β-glucan antibody clones and their respective antigen-binding Fabs were tested using biolayer interferometry (BLI) assays and immunofluorescence staining. In vivo binding of the Zirconium-89 labeled antibodies/Fabs to fungal pathogens was then evaluated using PET/CT imaging in mouse models of fungal infection, bacterial infection and sterile inflammation.</p><p><strong>Results: </strong>One of the evaluated antibodies (HA-βG-Ab) and its Fab (HA-βG-Fab) bound to β-glucans with high affinity (K<sub>D</sub> = 0.056 & 21.5 nM respectively). Binding to the fungal cell wall was validated by immunofluorescence staining and in vitro binding assays. ImmunoPET imaging with intact antibodies however showed slow clearance and high background signal as well as nonspecific accumulation in sites of infection/inflammation. Conversely, specific binding of [<sup>89</sup>Zr]Zr-DFO-HA-βG-Fab to sites of fungal infection was observed when compared to the isotype control Fab and was significantly higher in fungal infection than in bacterial infection or sterile inflammation.</p><p><strong>Conclusions: </strong>[<sup>89</sup>Zr]Zr-DFO-HA-βG-Fab can be used to detect fungal infections in vivo. Targeting distinct components of the fungal cell wall is a viable approach to developing fungal-specific PET tracers.</p>","PeriodicalId":11909,"journal":{"name":"European Journal of Nuclear Medicine and Molecular Imaging","volume":null,"pages":null},"PeriodicalIF":8.6000,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11368974/pdf/","citationCount":"0","resultStr":"{\"title\":\"PET imaging of Aspergillus infection using Zirconium-89 labeled anti-β-glucan antibody fragments.\",\"authors\":\"Jianhao Lai, Swati Shah, Neysha Martinez-Orengo, Rekeya Knight, Eyob Alemu, Mitchell L Turner, Benjamin Wang, Anna Lyndaker, Jianfeng Shi, Falguni Basuli, Dima A Hammoud\",\"doi\":\"10.1007/s00259-024-06760-4\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Purpose: </strong>Invasive fungal diseases, such as pulmonary aspergillosis, are common life-threatening infections in immunocompromised patients and effective treatment is often hampered by delays in timely and specific diagnosis. Fungal-specific molecular imaging ligands can provide non-invasive readouts of deep-seated fungal pathologies. In this study, the utility of antibodies and antibody fragments (Fab) targeting β-glucans in the fungal cell wall to detect Aspergillus infections was evaluated both in vitro and in preclinical mouse models.</p><p><strong>Methods: </strong>The binding characteristics of two commercially available β-glucan antibody clones and their respective antigen-binding Fabs were tested using biolayer interferometry (BLI) assays and immunofluorescence staining. In vivo binding of the Zirconium-89 labeled antibodies/Fabs to fungal pathogens was then evaluated using PET/CT imaging in mouse models of fungal infection, bacterial infection and sterile inflammation.</p><p><strong>Results: </strong>One of the evaluated antibodies (HA-βG-Ab) and its Fab (HA-βG-Fab) bound to β-glucans with high affinity (K<sub>D</sub> = 0.056 & 21.5 nM respectively). Binding to the fungal cell wall was validated by immunofluorescence staining and in vitro binding assays. ImmunoPET imaging with intact antibodies however showed slow clearance and high background signal as well as nonspecific accumulation in sites of infection/inflammation. Conversely, specific binding of [<sup>89</sup>Zr]Zr-DFO-HA-βG-Fab to sites of fungal infection was observed when compared to the isotype control Fab and was significantly higher in fungal infection than in bacterial infection or sterile inflammation.</p><p><strong>Conclusions: </strong>[<sup>89</sup>Zr]Zr-DFO-HA-βG-Fab can be used to detect fungal infections in vivo. Targeting distinct components of the fungal cell wall is a viable approach to developing fungal-specific PET tracers.</p>\",\"PeriodicalId\":11909,\"journal\":{\"name\":\"European Journal of Nuclear Medicine and Molecular Imaging\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":8.6000,\"publicationDate\":\"2024-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11368974/pdf/\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"European Journal of Nuclear Medicine and Molecular Imaging\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1007/s00259-024-06760-4\",\"RegionNum\":1,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2024/5/24 0:00:00\",\"PubModel\":\"Epub\",\"JCR\":\"Q1\",\"JCRName\":\"RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Journal of Nuclear Medicine and Molecular Imaging","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s00259-024-06760-4","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/5/24 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING","Score":null,"Total":0}
引用次数: 0
摘要
目的:肺曲霉菌病等侵袭性真菌疾病是免疫力低下患者常见的危及生命的感染,而有效的治疗往往因延误及时和具体的诊断而受阻。真菌特异性分子成像配体可提供深层真菌病变的非侵入性读数。本研究在体外和临床前小鼠模型中评估了针对真菌细胞壁中β-葡聚糖的抗体和抗体片段(Fab)检测曲霉感染的实用性:方法:采用生物层干涉测量法(BLI)和免疫荧光染色法测试了两种市售β-葡聚糖抗体克隆及其各自的抗原结合Fabs的结合特性。然后在真菌感染、细菌感染和无菌性炎症的小鼠模型中使用 PET/CT 成像评估了锆-89 标记的抗体/Fabs 与真菌病原体的体内结合情况:结果:其中一种被评估的抗体(HA-βG-Ab)及其Fab(HA-βG-Fab)与β-葡聚糖的结合亲和力很高(KD分别为0.056和21.5 nM)。与真菌细胞壁的结合通过免疫荧光染色和体外结合试验进行了验证。然而,使用完整抗体进行的免疫 PET 成像显示,清除速度慢,背景信号高,并且在感染/炎症部位有非特异性积累。相反,与同型对照Fab相比,[89Zr]Zr-DFO-HA-βG-Fab与真菌感染部位的特异性结合在真菌感染中明显高于细菌感染或无菌性炎症:结论:[89Zr]Zr-DFO-HA-βG-Fab可用于检测体内真菌感染。靶向真菌细胞壁的不同成分是开发真菌特异性 PET 示踪剂的可行方法。
PET imaging of Aspergillus infection using Zirconium-89 labeled anti-β-glucan antibody fragments.
Purpose: Invasive fungal diseases, such as pulmonary aspergillosis, are common life-threatening infections in immunocompromised patients and effective treatment is often hampered by delays in timely and specific diagnosis. Fungal-specific molecular imaging ligands can provide non-invasive readouts of deep-seated fungal pathologies. In this study, the utility of antibodies and antibody fragments (Fab) targeting β-glucans in the fungal cell wall to detect Aspergillus infections was evaluated both in vitro and in preclinical mouse models.
Methods: The binding characteristics of two commercially available β-glucan antibody clones and their respective antigen-binding Fabs were tested using biolayer interferometry (BLI) assays and immunofluorescence staining. In vivo binding of the Zirconium-89 labeled antibodies/Fabs to fungal pathogens was then evaluated using PET/CT imaging in mouse models of fungal infection, bacterial infection and sterile inflammation.
Results: One of the evaluated antibodies (HA-βG-Ab) and its Fab (HA-βG-Fab) bound to β-glucans with high affinity (KD = 0.056 & 21.5 nM respectively). Binding to the fungal cell wall was validated by immunofluorescence staining and in vitro binding assays. ImmunoPET imaging with intact antibodies however showed slow clearance and high background signal as well as nonspecific accumulation in sites of infection/inflammation. Conversely, specific binding of [89Zr]Zr-DFO-HA-βG-Fab to sites of fungal infection was observed when compared to the isotype control Fab and was significantly higher in fungal infection than in bacterial infection or sterile inflammation.
Conclusions: [89Zr]Zr-DFO-HA-βG-Fab can be used to detect fungal infections in vivo. Targeting distinct components of the fungal cell wall is a viable approach to developing fungal-specific PET tracers.
期刊介绍:
The European Journal of Nuclear Medicine and Molecular Imaging serves as a platform for the exchange of clinical and scientific information within nuclear medicine and related professions. It welcomes international submissions from professionals involved in the functional, metabolic, and molecular investigation of diseases. The journal's coverage spans physics, dosimetry, radiation biology, radiochemistry, and pharmacy, providing high-quality peer review by experts in the field. Known for highly cited and downloaded articles, it ensures global visibility for research work and is part of the EJNMMI journal family.