Journal: Oncoimmunology
Article Title: A novel multimeric IL15/IL15Rα-Fc complex to enhance cancer immunotherapy
doi: 10.1080/2162402X.2021.1893500
Figure Lengend Snippet: In vitro characterization of IL15/IL15Rα-Fc complexes . (a) Schematic diagrams of all four IL15/IL15Rα-Fc complexes in theoretical dimeric Fc fusion formats. (b) All four complexes were shown on reduced SDS-PAGE, before and after deglycosylation treatment, using Invitrogen SeeBlue Plus2 Pre-Stained Standard as the protein molecular weight (MW) marker. (c) WT-FL complex on SDS-PAGE under reduced and non-reduced conditions, using Life Technologies BenchMark Unstained Protein Ladder as the protein MW marker (the size of selected bands was shown), with IL15Rα-Fc and IL15 bands were marked with arrows. (d) SE-HPLC chromatography using G4000SW column. Major peak of WT-FL (19.0 minutes) corresponding to MW around 600 kDa, and SU complexes (22.3 minutes) corresponding to around 120 kDa, and salt buffer peak (26.5 minutes). (e) SE-HPLC results of the 6 standard MW marker (Sigma Gel Filtration Markers Kit) mixed together. Each MW marker was also run separately to confirm the position, except for the 150 and 66 kDa markers which did not separate in the mixture. (f) The fitted curve for WT-FL complex MW calculation. The size of 600 kDa of the WT-FL complex was calculated based on the fitted curve derived from the top three high MW standard markers that was run separately. (g) Schematic diagram of WT-FL complex in hexameric format, and accelerated stability test of WT-FL at 37°C over 4 weeks; monomer % represents the percentage of monomers in HPLC profile for each time point, based on AUC analysis excluding buffer peak. (h) In vitro cell proliferation assays using mouse lymphoblast cell line CTLL-2. Mean + SD (n = 3). * p < .0001 when FL-complexes treatment groups were compared with SU-complexes treatment groups at indicated concentration, respectively
Article Snippet: IL15/IL15Rα-Fc titer was determined by ELISA, where plates were coated with anti-human IL15 polyclonal goat IgG (R&D Systems) to capture the complex, and then detected with secondary goat anti-human IgG (Fc specific) (Southern Biotech).
Techniques: In Vitro, SDS Page, Staining, Molecular Weight, Marker, Chromatography, Filtration, Derivative Assay, Concentration Assay