Simultaneous Photoradiochemical Labelling of Antibodies for Immuno-PET
50 Pages Posted: 29 Jan 2019 Sneak Peek Status: Review CompleteMore...
A method for the simultaneous, one-step photochemical conjugation and 89Zr-radiolabelling of antibodies is introduced. A photoactivativable chelate based on the functionalisation of desferrioxamine B with an arylazide moiety (DFO-ArN3, ) was synthesised. The radiolabelled complex, 89Zr-1+ was produced and characterised. Density functional theory (DFT) calculations were used to investigate the mechanism of arylazide photoactivation. 89Zr-radiolabelling experiments were also used to determine the efficiency of photochemical conjugation. A standard two-step approach gave a measured conjugation efficiency of 3.50.4%. In contrast, the new one-step process gave a higher photoradiolabelling efficiency of ~76%. Stability measurements, cellular saturation binding assays, PET imaging and biodistribution studies in mice bearing SK-OV-3 tumours confirmed the biochemical viability and tumour specificity of photoradiolabelled [89Zr]ZrDFO-azepin-trastuzumab. Experimental data support the conclusion that the combination of photochemistry and radiochemistry is a viable strategy for producing radiolabelled proteins for imaging and therapy.
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