Definition

A radiotracer composed of hGZP, a biotinylated human granzyme B peptide, conjugated with the bifunctional, macrocyclic chelating agent 1,4,7-triazacyclononane-N,N’,N”-triacetic acid (NOTA) and labeled with the radionuclide gallium Ga 68, with potential imaging activity using positron emission tomography (PET). Upon administration, the hGZP moiety of gallium Ga 68-NOTA-hGZP targets and binds to granzyme B, a cytotoxic serine protease released by cytotoxic T lymphocytes (CTLs), in tumors. Upon PET imaging, tumoral granzyme B expression can be visualized, and CTL activation and activity can be assessed.