A Dual-Modality Linker Enables Site-Specific Conjugation of Antibody Fragments for 18F-Immuno-PET and Fluorescence Imaging.
J Nucl Med
; 60(10): 1467-1473, 2019 10.
Article
en En
| MEDLINE
| ID: mdl-30877181
ABSTRACT
Antibody-based dual-modality (PET/fluorescence) imaging enables both presurgery antigen-specific immuno-PET for noninvasive whole-body evaluation and intraoperative fluorescence for visualization of superficial tissue layers for image-guided surgery. Methods:
We developed a universal dual-modality linker (DML) that facilitates site-specific conjugation to a cysteine residue-bearing antibody fragment, introduction of a commercially available fluorescent dye (via an amine-reactive prosthetic group), and rapid and efficient radiolabeling via click chemistry with 18F-labeled trans-cyclooctene (18F-TCO). To generate a dual-modality antibody fragment-based imaging agent, the DML was labeled with the far-red dye sulfonate cyanine 5 (sCy5), site-specifically conjugated to the C-terminal cysteine of the anti-prostate stem cell antigen (PSCA) cys-diabody A2, and subsequently radiolabeled by click chemistry with 18F-TCO. The new imaging probe was evaluated in a human PSCA-positive prostate cancer xenograft model by sequential immuno-PET and optical imaging. Uptake in target tissues was confirmed by ex vivo biodistribution.Results:
We successfully synthesized a DML for conjugation of a fluorescent dye and 18F. The anti-PSCA cys-diabody A2 was site-specifically conjugated with either DML or sCy5 and radiolabeled via click chemistry with 18F-TCO. Immuno-PET imaging confirmed in vivo antigen-specific targeting of prostate cancer xenografts as early as 1 h after injection. Rapid renal clearance of the 50-kDa antibody fragment enables same-day imaging. Optical imaging showed antigen-specific fluorescent signal in PSCA-positive xenografts and high contrast to surrounding tissue and PSCA-negative xenografts.Conclusion:
The DML enables site-specific conjugation away from the antigen-binding site of antibody fragments, with a controlled linker-to-protein ratio, and combines signaling moieties for 2 imaging systems into 1 molecule. Dual-modality imaging could provide both noninvasive whole-body imaging with organ-level biodistribution and fluorescence image-guided identification of tumor margins during surgery.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Neoplasias de la Próstata
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Carbocianinas
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Radioisótopos de Flúor
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Ciclooctanos
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Tomografía de Emisión de Positrones
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Microscopía Fluorescente
Límite:
Animals
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Humans
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Male
Idioma:
En
Revista:
J Nucl Med
Año:
2019
Tipo del documento:
Article