[111In]In-DTPA-CTP

[111In]In-DTPA-CTP is a novel radiopharmaceutical bioconjugate designed for the non-invasive, longitudinal tracking of therapeutic cells in vivo using Single Photon Emission Computed Tomography (SPECT). Developed by researchers at King's College London, the agent utilizes a synthetic "cytotopic" peptide (CTP) that anchors to the extracellular surface of cell membranes. The CTP component consists of two long-chain myristoyl groups that insert into the cellular phospholipid bilayer and multiple positively charged lysine residues that facilitate electrostatic interactions with negatively charged phospholipid headgroups. This peptide is conjugated via a maleimide-thiol linkage to a diethylenetriamine pentaacetate (DTPA) chelator, which coordinates the gamma-emitting radioisotope Indium-111. Unlike traditional cell-labelling methods that rely on cellular internalization or covalent modification of surface proteins, [111In]In-DTPA-CTP localizes the radionuclide to the cell membrane, potentially reducing radiotoxicity to the cell nucleus from Auger electrons. While proof-of-concept studies in murine myeloma models demonstrated successful lung tracking immediately after administration, the agent's current limitation is its relatively rapid dissociation from cell membranes in the presence of serum proteins.

Other names

Indium-111-labelled cytotopic peptideIndium111-labelled cytotopic peptideIndium 111-labelled cytotopic peptideIndium-111-DTPA-CTPIndium111-DTPA-CTPIndium 111-DTPA-CTPradiolabelled cell-membrane binding peptide