Tumor-associated antigens targeted by Indium-111-labeled monoclonal antibodies

Monoclonal antibody targets via In-111-labeled antibodies refers to a diverse group of cell-surface antigens and receptors utilized for diagnostic radioimmunoscintigraphy. Indium-111 is a cyclotron-produced radioisotope that decays via electron capture with a half-life of 67.3 hours, emitting gamma photons suitable for single-photon emission computed tomography (SPECT) imaging [1]. These targets, such as Prostate-Specific Membrane Antigen (PSMA), Carcinoembryonic Antigen (CEA), and Tumor-Associated Glycoprotein 72 (TAG-72), are typically overexpressed in malignant tissues compared to normal cells [2, 3]. The interaction involves the high-affinity binding of a radiolabeled monoclonal antibody to the extracellular domain of the target protein, facilitating the localization of primary tumors and metastatic sites [4, 5]. Historically, these targets provided a pathway for theranostics, where In-111 imaging was used to predict the biodistribution of subsequent therapeutic radioisotopes like Yttrium-90 [4]. While many of these diagnostic agents have been replaced by PET-based tracers, the underlying targets remain critical in oncology for both imaging and targeted therapy [5].

Other names

In-111-labeled mAb targetsRadioimmunoscintigraphy targetsIndium-111 radiopharmaceutical targetsIn-111-labeled antibody targets

The mechanism involves the systemic administration of a monoclonal antibody conjugated to the radioisotope Indium-111 via a chelating agent. The antibody binds with high specificity to its cognate antigen expressed on the surface of target cells. The gamma radiation emitted by Indium-111 is then detected by a gamma camera using SPECT, allowing for the non-invasive visualization of target-positive tissues [1, 5].