Immuno-PET – Precision Imaging of Antibody Biodistribution
With hundreds of monoclonal antibodies (mAb), antibody fragments, antibody drug conjugates, and other antibody scaffolds in development, the use of immuno-PET in preclinical research for in vivo tracking and quantification of these compounds has advanced rapidly. MI Bioresearch has been at the forefront of this advancement, being one of the first commercial CROs to offer immuno-PET to biotechnology drug developers.
In combining our state-of-the-art small animal bimodal PET/CT and trimodal PET/SPECT/CT instruments with our rodent models expertise, we can image time-resolved and quantitative biodistribution of radiolabeled biologics in naïve and disease bearing animals. We work with trusted radiochemistry partners to develop a radiolabeling protocol for your biologic and coordinate delivery to our site of the radiolabeled biologic for in vivo study. We are licensed to work with a range of positron emitters including zirconium-89 (89Zr) and iodine-124 (124I), commonly used in immuno-PET.
|Isotope||Half Life||Energy in KeV||Common Applications/Strengths|
|Technetium-99m [99mTc]||6 hours||140.5||Most common clinical SPECT isotope; bone imaging|
|Iodine-123 [123I]||13.2 hours||159||Neuro-imaging|
|Indium-111 [111In]||2.8 days||171.3, 245.4||Biodistribution|
|Gallium-67 [67Ga]||3.3 days||93.3, 184.6, 300||Translatable to [68Ga] PET radiotracer|
|Lutetium-177 [177Lu]||6.73 days||113, 210||Radiotherapy|
|Thallium-201 [201TI]||12.23 days||135, 167||Cardiac imaging|
|Tin-117m [117mSn]||14 days||158.6||Long-term biodistribution|
|Iodine-125 [125I]||59 days||27 to 32||Iodination|
|PET Isotope||Half Life||Common Applications|
|Fluorine-18 [18F]||1.8 hours||FLT, FDG|
|Copper-64 [64CU]||12.7 hours||Short term tacking of small molecules and peptides; imaging of disease state and efficacy using targeted biologics|
|Yttrium-86 [86Y]||14.7 hours||Analog of [90Y] radiotherapy isotope that can be used for imaging studies|
|Cobalt-55 [55Co]||17.5 hours||Characterization of tissue infarct regions|
|Iodine-124 [124I]||4.2 days||Iodination labeling of proteins|
|Zirconium-89 [89Zr]||3.27 days||Biodistrobutions|
Antibody Biodistribution In Vivo With Zirconium-89 PET
Zirconium-89 (89Zr) has revolutionized discovery and translation of Ab (and Ab fragment) therapeutics via PET biodistribution imaging. With standard, straightforward labeling chemistry, 89Zr provides unprecedented specificity and sensitivity of PET Ab detection (to pM levels). We use 89Zr PET as a platform assay for in vivo quantification of:
- Ab targeting precision
- Off-target localization
Our assays allow preclinical assessment of acute Ab kinetics as well as longitudinal time courses over >1 week in the whole body.
Determination of Biodistribution Using Fluorescence Imaging (FLI)
Efficient and quantitative characterization of biologics targeting and biodistribution can be achieved in a variety of tissues using 3D fluorescence imaging of fluorescent-labeled agents. A variety of fluorophore kits are available for antibody, protein, and nanoparticle labeling. Blood sampling and ex vivo imaging can be combined with in vivo imaging for further quantitation of pharmacokinetics and pharmacodynamics of systemically introduced biologics. We have extensive experience with these in vivo biodistribution studies that allow interrogation of targeting and kinetics during the early discovery phase, prior to more elaborate, translational radiolabeling approaches that are more labor- and cost-intensive.