UNLABELLED: Interleukin-2 (IL2) binds with high affinity to the IL2 receptors overexpressed on activated T lymphocytes in various pathologic conditions. Radiolabeling of IL2 with a positron-emitting isotope could provide a tool for noninvasive PET of activated T cells in immune-mediated diseases. We report the labeling of IL2 with N-succinimidyl 4-(18)F-fluorobenzoate ((18)F-SFB) for the synthesis of N-(4-(18)F-fluorobenzoyl)interleukin-2 ((18)F-FB-IL2) and the in vitro and in vivo evaluation of this novel radiopharmaceutical for the detection of IL2 receptor-positive cells by PET. METHODS: (18)F-SFB was efficiently prepared using a 3-step radiochemical pathway. Purified (18)F-SFB was incubated with IL2 in borate buffer (pH 8.5) and ethanol at 50°C for 10 min. (18)F-FB-IL2 was purified by reversed-phase high-performance liquid chromatography. As in vitro quality controls, a biologic binding assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis, mass spectrometry, and 3-chloroacetic acid precipitation stability tests were performed. Biodistribution studies were performed in BALB/c mice to evaluate the distribution of the tracer in healthy animals. PET experiments were performed in severe combined immunodeficiency disease mice inoculated with phytohemoagglutinin-activated human peripheral blood mononuclear cells (hPBMc). Whole-body images were acquired 30 min after injection of 5-15 MBq of (18)F-FB-IL2. RESULTS: (18)F-SFB was produced with a 34%-38% radiochemical yield. The radiochemical purity after solid-phase extraction purification ranged from 93% to 96%. Conjugation of (18)F-SFB to IL2 yielded (18)F-FB-IL2 as the major product. The radiochemical yield of (18)F-FB-IL2 after high-performance liquid chromatography purification was 25%-35% based on (18)F-SFB. (18)F-FB-IL2 was stable in plasma at 37°C and capable of stimulating T cells to an extent similar to native IL2. A biodistribution study showed highest tracer uptake in the kidneys and bladder due to rapid renal clearance of the tracer. Small-animal PET images showed binding of (18)F-FB-IL2 to activated hPBMc proportional to the number of injected cells. CONCLUSION: We report the successful labeling of IL2 with (18)F for PET of activated T lymphocytes. (18)F-FB-IL2 is stable, is biologically active, and allows in vivo detection of activated T lymphocytes.
UNLABELLED: Interleukin-2 (IL2) binds with high affinity to the IL2 receptors overexpressed on activated T lymphocytes in various pathologic conditions. Radiolabeling of IL2 with a positron-emitting isotope could provide a tool for noninvasive PET of activated T cells in immune-mediated diseases. We report the labeling of IL2 with N-succinimidyl 4-(18)F-fluorobenzoate ((18)F-SFB) for the synthesis of N-(4-(18)F-fluorobenzoyl)interleukin-2 ((18)F-FB-IL2) and the in vitro and in vivo evaluation of this novel radiopharmaceutical for the detection of IL2 receptor-positive cells by PET. METHODS: (18)F-SFB was efficiently prepared using a 3-step radiochemical pathway. Purified (18)F-SFB was incubated with IL2 in borate buffer (pH 8.5) and ethanol at 50°C for 10 min. (18)F-FB-IL2 was purified by reversed-phase high-performance liquid chromatography. As in vitro quality controls, a biologic binding assay, sodium dodecyl sulfatepolyacrylamide gel electrophoresis, mass spectrometry, and 3-chloroacetic acid precipitation stability tests were performed. Biodistribution studies were performed in BALB/c mice to evaluate the distribution of the tracer in healthy animals. PET experiments were performed in severe combined immunodeficiency diseasemice inoculated with phytohemoagglutinin-activated human peripheral blood mononuclear cells (hPBMc). Whole-body images were acquired 30 min after injection of 5-15 MBq of (18)F-FB-IL2. RESULTS: (18)F-SFB was produced with a 34%-38% radiochemical yield. The radiochemical purity after solid-phase extraction purification ranged from 93% to 96%. Conjugation of (18)F-SFB to IL2 yielded (18)F-FB-IL2 as the major product. The radiochemical yield of (18)F-FB-IL2 after high-performance liquid chromatography purification was 25%-35% based on (18)F-SFB. (18)F-FB-IL2 was stable in plasma at 37°C and capable of stimulating T cells to an extent similar to native IL2. A biodistribution study showed highest tracer uptake in the kidneys and bladder due to rapid renal clearance of the tracer. Small-animal PET images showed binding of (18)F-FB-IL2 to activated hPBMc proportional to the number of injected cells. CONCLUSION: We report the successful labeling of IL2 with (18)F for PET of activated T lymphocytes. (18)F-FB-IL2 is stable, is biologically active, and allows in vivo detection of activated T lymphocytes.
Authors: S V Hartimath; O Draghiciu; S van de Wall; V Manuelli; R A J O Dierckx; H W Nijman; T Daemen; E F J de Vries Journal: Oncoimmunology Date: 2016-11-18 Impact factor: 8.110
Authors: John A Ronald; Byung-Su Kim; Gayatri Gowrishankar; Mohammad Namavari; Israt S Alam; Aloma D'Souza; Hidekazu Nishikii; Hui-Yen Chuang; Ohad Ilovich; Chih-Feng Lin; Robert Reeves; Adam Shuhendler; Aileen Hoehne; Carmel T Chan; Jeanette Baker; Shahriar S Yaghoubi; Henry F VanBrocklin; Randall Hawkins; Benjamin L Franc; Salma Jivan; James B Slater; Emily F Verdin; Kenneth T Gao; Jonathan Benjamin; Robert Negrin; Sanjiv Sam Gambhir Journal: Cancer Res Date: 2017-06-01 Impact factor: 12.701
Authors: Andor W J M Glaudemans; Elena Bonanno; Filippo Galli; Clark J Zeebregts; Erik F J de Vries; Michel Koole; Gert Luurtsema; Hendrikus H Boersma; Maurizio Taurino; Riemer H J A Slart; Alberto Signore Journal: Eur J Nucl Med Mol Imaging Date: 2014-04-16 Impact factor: 9.236