PT - JOURNAL ARTICLE AU - Shi, Dai AU - Cheng, Yuan AU - Cheng, Dengfeng AU - Shi, Hongcheng TI - <strong>Preparation and quality control of mAb-F(ab')2</strong> DP - 2022 Aug 01 TA - Journal of Nuclear Medicine PG - 2843--2843 VI - 63 IP - supplement 2 4099 - http://jnm.snmjournals.org/content/63/supplement_2/2843.short 4100 - http://jnm.snmjournals.org/content/63/supplement_2/2843.full SO - J Nucl Med2022 Aug 01; 63 AB - 2843 Introduction: Monoclonal antibodies (mAbs) have large molecular weights, slow metabolism, and long half-life nuclide-labeled monoclonal antibodies are difficult to clinically apply due to the large cumulative radiation dose. In this study, the specific recognition feature of IdeS enzyme was used to prepare mAb-F(ab')2 by taking Cetuximab as an example.Methods: Cetuximab was dissolved in PBS with 0.01M pH=7.4, and an appropriate amount of IdeS enzyme was added. After 30 minutes at 37&amp;deg;C, a mixture of Cetuximab-F(ab')2, Cetuximab-Fc and IdeS enzymes was obtained; use excess Protein A magnetic beads to adsorb Cetuximab - Fc and 40 K Zeba desalting column purification to yield mAb-F(ab')2. In terms of quality control, product purity was assessed by 4%-15% SDS-PAGE gel electrophoresis and Coomassie brilliant blue staining. Antibody activity identification: Conjugated with Cetuximab-F(ab')2-cy3 and Cetuximab-cy3 as fluorescent probes, added to MGC803 cell culture medium at a final concentration of 0.001 &amp;mu;g/mL, and observed by fluorescence microscope 12 hours later.Results: By SDS-PAGE staining with Coomassie brilliant blue, the protein band of Cetuximab was about 150 kDa and Cetuximab-F(ab')2 was about 100 kDa. Through fluorescence microscope observation, the binding amount of MGC803 cells to Cetuximab-F(ab')2-cy3 and Cetuximab-cy3 fluorescent probes is similar (p&gt;0.05), which proves that the binding force of Cetuximab-F(ab')2 is similar to that of Cetuximab-F(ab')2. Total resistance is similar.Conclusions: IdeS enzymatic cleavage can obtain mAb-F(ab')2 with similar activity and smaller molecular weight.